Insulating an old house: What to do!

[@kurtriexinger6097]

Don’t sacrifice the long term integrity of a home for short term comfort! - this is spot on. Working exclusively on 100+ year old houses in Philadelphia I have definitely seen what you describe. So called improvements have frequently been the cause of permanent damage and loss of historic homes. So much construction info on KZbin focuses only on newer homes and much needs to be thought through critically before applying to an older home. Great to hear from someone who understands and appreciates what we have in these homes. They are a treasure! Thanks Brent!

[@BrentHull]

Nice. Thanks for watching.

[@rafars2246]

That could be the result of poor work. Insulating a home can't have any negative side effect, only positive.

[@bobloblaw10001]

@Rafa RS If there is a water problem, insulation and especially spray foam will make it worse because the water becomes trapped and is often hard to notice until significant damage has occurred.

[@bobloblaw10001]

I personally think that climate change and rising energy costs make the risk worth it to super insulate and air seal as much as possible. Obviously try to identify active and potential water problems before insulating.

[@rafars2246]

@@bobloblaw10001 true. Terrible thing to do.

[@taylorjensen6181]

This info is saving our 1938 house right now! (It’s built more like those 1800’s homes, however, with no tar layer). Our contractor was so close to ripping out all of our historic lath and plaster and blowing in cellulose. Just thinking if we hadn’t done our research, it’s likely we could’ve lost our old growth cedar and fir home. We instead are so lucky to have found your channel and have the language to communicate why we need to insulate the attic and basement only. Thank you for your expertise and clarity on these issues!

[@BrentHull]

Awesome! I'm so glad it is helping.

[@vapeurdepisse]

Be careful trusting just one voice on the Internet

[@taylorjensen6181]

In my experience, the information in this video has been confirmed by many pre-war home experts, with this knowledge being relatively common at this point overseas in Europe where they have had to reconsider modern methods in favor of keeping their historic buildings intact -- buildings which have stood strong for hundreds of years only to crumble and rot with insensitive modern treatments (take the "waterproofing" disaster in the UK, for instance). In my experience, the average American/new construction contractor is completely oblivious to this kind of wholistic house treatment and sacrificing short-term comfort for longevity when it comes to retrofitting/restoring pre-war homes, probably in part to how we rarely have buildings older than the early 1800's in most parts of the country and have very few remaining craftspeople to keep the knowledge alive within the cheap+fast construction business. In a consumer society, we are very quick to adopt the cheapest, fastest way of "improving," things, rather than to think about the longevity and beauty of buildings. I think your concern is better spent elsewhere.

[@taylorjensen6181]

@@vapeurdepisse and that's aside from the fact that Brent Hull happens to be one of the experts in his field in revitalizing traditional building knowledge in the United States. He is more than a valid source of knowledge. Sources matter :)

[@vapeurdepisse]

@@taylorjensen6181 not sure what part of Europe you're talking about but the majority of Europe had been using masonry construction for thousands of years. Stick framing is not a thing in Europe.

[@scottthomas7875]

So important that you said " when you introduce technology to and old home you create longevity issues". More people need to understand how old home function. Thank you excellent topic.

[@BrentHull]

Thanks for watching.

[@michaela5261]

This is great information for anyone thinking of insulating thier historical home. I own a 1882 double brick home and was faced with this as well, we had an energy audit contractor come in while I was renovating my home and he strongly advised to foam it. I told him to take a hike... Alot of these experts have no clue. I built my interior walls 3/4 of an inch off the brick. Essentially creating a double brick veneer, then insulated with rock wool. These old places need to breath! As a carpenter I've seen alot of hack jobs ruin beautiful old homes. I'm so glad to see information like this posted.

[@BrentHull]

Nice. Thanks for sharing.

[@fatfatr]

your exterior wall is going to be cold and moisture will condense in your cavity causing mold or other problems

[@michaela5261]

@@fatfatr not in this situation. There is airflow between the brick and the insulated interior wall.

[@zaggnutt2772]

@@fatfatr Wrong. Do some research and learn why.

[@scarecrow26]

Very well said. We worked on some older houses in the 1980’s. My Dad and some of the other carpenters said what you were saying “let the wood breath”. insulation experts would say something different to sell the insulation. Yet 15 years later those houses had some to a lot of rotting wood. As a carpenter I learned to lesson to my Dad.

[@BrentHull]

Thanks for sharing.

[@AmandaComeauCreates]

Insulation and air sealing and vapour retarding material installation are all different things. Homes should breath through their ventilation systems. But you provide vapour open layers that allow water if not air to pass through a wall cavity.

[@HerbaceousM8]

most insulation experts would say you need an air gap to allow drying to the outside, to make it into a pseudo rain screen. some sort of spacer or dimple mat needs to be on the outside wall to allow for drying top to bottom, like a vented attic space

[@katysummer9418]

Well every wood worker should know that "Wood needs air circulation = breathe" if there is trapped moisture sure it starts to rot.

[@seanstack180]

Wood doesn’t have lungs and therefore doesn’t need to breathe.

[@historicspecialist7773]

This is wonderful. I’ve worked on historic homes for 18 years. I have had really bad experience with spray foam. I’ve never done it but I always got the calls about mildew and windows “leaking” but it was always the spray foam that caused the problem and I had to remove it, repair and go back with more friendly and compatible materials and problem was solved. I love this video because it’s reassuring and does make me feel better in a weird way for taking all the hate for years when I spoke against it. Building envelop design is very important and love these channels! Thank you for posting this video

[@BrentHull]

Thanks for watching.

[@dosadoodle]

I think you know Matt and all the Building Science folks would agree with your decision-making here. :) I can hear Matt saying the line he loves to quote from David Nicastro: "If it can't dry, it's gonna die."

[@BrentHull]

Good point. Thanks.

[@bobloblaw10001]

But it will rot anyway just a bit slower.

[@a97chrjo]

In Sweden the preferred method of insulation is cellulose insulation in old houses because it can absorb moisture and slowly release it when it is drier.

[@BrentHull]

Agreed. That is what I like as well.

[@iposttvshows]

any idea if this can help reduce vibrational sounds in a shared side by side common wall in a duplex?

[@a97chrjo]

@@iposttvshows Maybe slightly better. Sense it are heavy than Rockwool

[@iposttvshows]

@@a97chrjo cellulose is heavier than Rockwool. Thank you for that. And from what I've researched, it's packed pretty dense which should help as well.

[@a97chrjo]

@@iposttvshows I think the easiest way to lower sound is to put a couple of extra layer of sheetrock/drywall.

[@lindacgrace2973]

So true! I also follow UK channels. There was a movement in the 80s to "waterproof" historic buildings in England. Out with the old high-maintenance cob and timber, in with the new waterproof pebble dash. To their horror, the Brtits discovered that the "waterproofing" merely trapped water inside the structure. Fabulous old buildings that had survived perfectly sound for hundreds of years - rotted away in less than 10 years! Now there is a huge movement to return historic materials to historic buildings - even Georgian homes with completely modern style inside (no original architectural features) are changing from "modern" plastics to traditional materials for longevity. This is some GREAT content! I maintain that clay and lime plasters (both traditional interior finishes) are brilliant for moderating humidity. I have been informed (by Corbin Lunsford and Matt Risinger, no less) that I am delusional. Lime plaster walls are NOT cooler in the summer and warmer in the winter. Clay plaster walls do not absorb and release humidity, thus tempering humidity. I'm a nut job for thinking that the plastering and ventilating techniques first developed before the days of Ancient Egypt (and in continuous use in the Middle East ever since) is completely pointless. To achieve moisture control you HAVE to use plastic barriers and expensive high-cost, high-maintenance equipment. Sigh. Keep hammering away with REAL scientific evidence and maybe we'll make a dent in the "plastic and foam is the solution for every building challenge" crowd!

[@BrentHull]

Well said. Thanks.

[@koenraadprincen7212]

Plastic barriers are NOT needed for controlling moisture levels... take a look at hempcrete. Using lime to control the moisture level in a wall demands more than "just a plaster". First, you need a capillary active wall material, like brick, and you need to build up the rendering from coarse to fine, finishing it with a lime paint (applied "wet in wet").

[@lindacgrace2973]

@@koenraadprincen7212Good point!

[@TheSwissChalet]

Sounds like the "bacteria and viruses cause disease" lie that has been perpetuated for over a century...and people believe...because "the experts" say so.

[@boardgamewoodsman8378]

Thanks for your videos. Remodeling a 1936 house right now built exactly like your third example. Very helpful

[@BrentHull]

Thanks for watching.

[@ZachAshcraft]

Love rockwool, think it’s a great solution for modern built houses too

[@BrentHull]

AGREED!

[@gardencity3558]

My go to for really old buildings as well. Animals / pests don't seem to like it. Fire reistant as well. Great for balloon framed walls.

[@thefack149]

ROCKS DON'T BURN

[@shannoneckelbarger5566]

Your knowledge is absolutely historical in itself! Thank you so much

[@BrentHull]

THanks.

[@kleo5187]

You are bringing vital topics to discussion with all your videos. Thanks for taking time to educate and encourage better building!

[@BrentHull]

So nice of you, you're welcome.

[@bonniehyden962]

Brent, here we are in Deep East Texas, moved into a 430-ish sq ft, shotgun house with a windowed sleeping porch built on the east side. Drop siding outside. Hardwood floor. Sheetrock inside. Maybe...beadboard under sheetrock. 🤷‍♀️ Sitting on blocks about 18-24" high. 18 wood frame, single pane windows: avg. 3 ea. room, 9 on that sleeping porch. My dad insulated the ceiling but there is no insulation in the walls. We figure the house to be 100-ish yrs old. Window unit AC. Small, soapstone, wood heater for heat. Over the hottest part of the summer I found the house to consistently stay 15°-20° cooler than outside without AC. However, I was worried about winter. ...there was no need. We're finding this grand, little house to be quite easy to keep warm! I just woke and built up the fire. Here in the kitchen it's 56°...it's 31° outside. In an hour or so it will be a toasty 70° here in the kitchen and 80°-85°on the sleeping porch where the heater sits. I'm translating my experience in historical sewing to old houses: we forget that people of long ago are just like us in that they liked to be comfortable, too. We just aren't knowledgeable or comfortable with their ways of being comfortable. Back in the day, a wood stove would have been in this kitchen. (And there will be one here again...soon! 😁) With a wood heater in the living area of the house, these houses would have heated quite well! ...and this house does heat very nicely! We just need to know how to work WITH the house....not make the house work with us and our modern, preconceived ideas of heating and cooling. Our ancestors knew what they were doing!

[@BrentHull]

Very insightful. Thanks for sharing.

[@RenovationFarmhouse]

No insulation here in my 1896 vernacular farmhouse in Maryland, just plaster walls, sheathing and 1960s era aluminum siding. Oil furnace for heat and I also have central air conditioning. Old growth wood still in great shape. Fascinating topic here, Brent. Thanks!

[@BrentHull]

Thanks!

[@willbass2869]

Energy bills?

[@Its_RichieRich]

How are the energy bills?

[@robinrobine8100]

Aluminum siding?? Yuk.

[@neilaleksandrov2655]

We need more thoughtful builders like yourself! Thank You for Your Quality! subscribed.

[@BrentHull]

Nice. Thanks for the sub.

[@beverlyboys73]

Great information. I agree, air gaps and the ability to breathe are very important for long-term. The best thing I did to eliminate roof ice dams was to add way more soffit vents and proper roof vents. The attic also has to breathe.

[@BrentHull]

Thanks for sharing.

[@907stovecraft8]

And plug holes that let heat into cold attics.

[@mbryan4964]

🥰it all just makes me bubble up with joy, yay for this channel. 🤗

[@BrentHull]

I'm so glad!

[@damianokon6209]

I tend to agree that mineral wool, generic term for Rockwool, is a great alternative for many projects. If there’s ability to breath, depending on climate, etc, you almost can’t go wrong with mineral wool. The product is rather forgiving in many respects as well!

[@BrentHull]

Agreed. Thanks.

[@bigbob3772]

Using rockwool in my 1870s all masonry home. Termites hate it, mold wont grow on it, doesn't absorb water- and water cannot harm it, doesn't burn and no critter tries to eat it. rockwool is perfect for older homes especially.

[@scotteric8711]

Rockwool is the way to go. I've chosen that for my home has well. This will be in combination with zip board material to replace the fiber barrier.

[@nikinthemidwest1915]

Yet another helpful video with sound reasoning and explanation beyond “just because i say so” 10/10!

[@BrentHull]

Wow, thanks!

[@kmonnier]

Great perspective and excellent presentation!

[@BrentHull]

Thank you!

[@rustyfreeman9528]

When I turned 11, we moved to what, then was the middle no were. My parents purchased an old house built 1893. It had been sawn in half right down the middle and moved in the dark of the night. Reassembled, and thats it. We did a lot of starting over those first few years. Learning can be a slow process. Don't give up keep working. It was so worth it.

[@BrentHull]

Thanks for that.

[@TheSwissChalet]

GREAT advice! Thanks Brent.

[@BrentHull]

Thx for watching.

[@ChrisDarjany]

Great video. Smart idea on the 1881 installing a dimple mat against the siding before installing the Rockwool. Genius.

[@BrentHull]

Thanks for watching!!

[@amyblueskyirl16]

I have a similar situation on my 120-year-old wood house and was just going to install regular batt insulation from the inside when removing the planks and then a vapor barrier on the inside before putting back on planks or drywall. Is there a reason to add a dimple against outer siding? Not much room there in the 2x4 walls

[@jessicavanburen-cc7qd]

Glad I’m learning this now. Better late than never. I probably never would have known

[@BrentHull]

Thanks for watching.

[@URBANENGINEER]

Thank you for the case studies!!

[@BrentHull]

Thanks for watching.

[@bser3973]

Thanks for the great information it will help me do some work in my home.

[@BrentHull]

Glad it was helpful!

[@mikeo1616]

amazing video, i learned so much! i never knew walls could breathe.

[@BrentHull]

Glad I could help!

[@Alex_441]

This video really helped me as i was wondering about the open cavities of my exterior walls of my house built in 1934. Redoing the attic insulation with new, thicker rockwool and leaving exterior walls alone. If it aint broke dont fix it.

[@BrentHull]

Thanks for watching.

[@classifiedinformation6353]

Thanks Brent for informing the builders who are working on old houses.Old houses are not new houses. If an owner of an old house wants to make their house feel be like a new house, they need to sell it and move into a new house. I have seen many an old house ruined by insensitive remuddeling. Tearing out original wood windows and installing smaller plastic "efficient" windows boils my blood. Sealing the wall cavities to prevent air flow is a ... bad idea. Portland cement with old brick kills an old house. I'm spending hundreds of hours removing the work of informed "handyman" mistakes. I just subscribed. Thanks for saving our historic built environment. John in Bethel, Missouri

[@BrentHull]

Nice, welcome aboard. I agree 100%

[@VonDerCoeur]

I'm so thankful for this video Also!!❤. I have 120 year old farm house with Asbestos siding with tar paper underneath. She's still standing strong and dry. But, i have been wanting to get the Asbestos off and replace with Exterior siding and some kind of insulation without ruining her ability to breathe.

[@BrentHull]

Are you sure the original siding was removed? I doubt it. I suspect the original siding is under the tar paper.

[@ikust007]

3:37 rare honesty . Bravo

[@BrentHull]

Thanks. . . not my proudest moment.

[@girlymel2323]

I know this is an old video but I’d love to see how you insulate the floor under the crawl space. Really how you deal with crawl spaces in general especially moisture. Thank you for all the informative videos the are so helpful

[@BrentHull]

Ok, thanks. We use Stega crawl. under houses. Good luck.

[@thenexthobby]

I'm a fan of mineral wool. Easy to work with, and won't turn into moldy goop if it gets a little damp.

[@BrentHull]

Word!

[@TonyaO2L]

Another great video, thanks!

[@BrentHull]

My pleasure!

[@myoldhousefix]

great video! I'll be sure to share this to our Old House Community! 👍

[@BrentHull]

Great. Thank you!!

[@lowellmccormick6991]

Our house in S. Louisiana was built in 1935 and has no vapor barrier and no insulation. It has 7/8" shiplap on the exterior and horizontal 1 x 12s on the interior. The interior walls were originally covered with a cheese cloth nailed to the wall and wallpaper on top of the cheese cloth. Later someone added paneling over the wallpaper. One room has sheetrock and it's the best insulated room. From one of my remodeling projects, I removed one of the pieces of sheetrock and there was no mold or rot. We ripped out the bathroom to wall studs and floor joists and found no mold or rot. So, I guess that as long as the area between the studs are clear, air movement prevents mold and rot. I've noticed that some folks have covered up their exterior wood siding with Tyvek, insulated the walls from the interior and covered the Tyvek with aluminum siding. Others have ripped off the exterior siding, installed a vapor barrier and insulation, planed the exterior wood siding and the reinstalled it. I'm going to stick with sheetrock over the interior wood walls.

[@BrentHull]

Yes, your walls can breathe and dry out if they get wet. Cheers.

[@schauv07]

YES!!! You said "BREATHE" again! Steve (architect) Baczek & Friends from Build Science 101 need to watch this. They talk about how they "put to bed" the discussion of a house's need to Breathe! They say it doesn't need to breathe, "if it did, why don't you leave your windows open?"?! What a ridiculous and unconvincing analogy! Thank you for "putting this to bed" at least for the logical thinkers.... :) Spencer

[@BrentHull]

Nice. Thx.

[@leestebbins5051]

Our 1897 had essentially zero insulation. Used what you call dimple mat in each stud bay directly against the siding followed by Tyvek, Rockwool, shiplap and drywall. Used foam under the floor and roof deck.

[@BrentHull]

Nice. Thanks.

[@613kc]

How about "rafter vents" under roof deck before foam. It's abt 1.5" thick

[@nabilaidoud6966]

Brent, I have an 1850 Victorian in Boston 2x6 rafters. Want to finish attic - thinking of doing just Rockwool. Would you do an air barrier like the dimple mat treatment for your roof decking. Just to be clear not going to nail to underside of roof - was wondering if there are other solutions

[@BareFace_Airsoft]

Love your videos. I learn something new everytime I watch!

[@BrentHull]

I'm so glad! Thanks!

[@ssoffshore5111]

I own a 1935 house in the northeast. I got sick of the exterior maintenance and the energy use. Ripped all the siding off, installed vinyl shakes with a very realistic look (and wrapped everything), did 1.5" of GPS foam board (for better breathability), with house wrap under it. Blown-in in the true 2x4 walls. Unknown how it's going to hold up, but it looks great from the street, and it's drastically reduced the energy bills. I know a lot of folks don't care for doing this to an old house, but I don't want to deal with painting for the rest of my years! Zero regrets so far and tons of compliments!

[@BrentHull]

Thanks for sharing.

[@piggly-wiggly]

My 1930s Cape Cod had an attic that the previous owner had closed in, with insulation under the roof and in the walls. Down on the first floor there was a vinyl wall covering. When I peeled off the vinyl, I saw mold on the back side. The house was built so that there was an air gap behind the brick and block walls that went up into the attic. When the attic was closed in, that gap was sealed with insulation, leaving the moisture nowhere to go, blocked even from migrating into the living space by the vinyl. One step after another, innocently taken, had led to moisture traps in the walls that were now food for termites and other critters coming up from the crawl space.

[@BrentHull]

Wow, great build science in your house. Thanks for sharing.

[@aaronvallejo8220]

Thank you for this information. We gutted our 1912 two story house last year. I installed lathe vertically in all the exposed 2x4 bays for an air gap. I then started fitting 2" foam in all the bays, then 1" foam with their perimeters all sealed with spray foam. I am now going to put poly vapour barrier and then another 1.5" of foam before the drywall. This will give us R27 walls.

[@BrentHull]

Nice. Thanks.

[@J_Money1]

in my 1916 house (Z6) instead of a dimple mat, i used .75" strips tacked to the studs and cut 2" EPS to fit the cavities (glued and then foamed in) to act as a weather barrier. I also had to fur out the walls further to add more mineral wool batt insulation to get me over R20 walls. Was a pain! might have to consider the dimple mat approach. Thank you

[@BrentHull]

Wow, ok, thanks for sharing. Keep us posted on performance.

[@johans7119]

Great to have another perspective. I used spray foam on our last project but had already decided not to use it again for the same reasons.

[@BrentHull]

Sounds like my progression. I used to use it but won't any more.

[@johans7119]

@@BrentHull Yes, it's just the idea of a leak going undetected! Rockwool exterior batt insulation seems to be the best for building science reasons (and wildfire) but not suitable for historic masonry. Thanks for the videos

[@OldHomeRescue]

Thanks for this! We were just having a conversation with an architect on a historic building where I was hesitant to give an opinion.

[@BrentHull]

Nice. Good luck.

[@TittleCreekOutdoors]

Awesome video thank you. The 1938 house is similar to what I have now with brick siding and shiplap sheathing. Now just to see if it has a tar paper barrier

[@BrentHull]

Glad it was helpful! Good luck.

[@SpanishEclectic]

This is important information. With old houses we need to think through how people lived when the house was built, and why certain things were done the same way for decades. I've seen/read about various homes from the 1800s where literal newspapers and Sears Catalogues were used inside the walls for insulation. Cellulose!

[@BrentHull]

Very true. Thanks.

[@Natedoc808]

The other aspect is updating the HVAC strategy to include a dehumidifier. Most of the moisture drive come from within the home.

[@BrentHull]

Agreed. Thx.

[@TheCdrbaby]

Thank you so much for confronting the foam issues wood needs to breath. A thing I always remember from fiberglassing is if you fully fiberglass a peas of wood it will rot. Wood needs to breath

[@BrentHull]

Thanks for sharing

[@CountyPatriot]

Thank you Brent!

[@BrentHull]

Your welcome! Thanks for watching.

[@FredMcIntyre]

Thanks for the info Brent! 😃👍🏻👊🏻

[@BrentHull]

Your welcome.

[@yssubed2]

Very useful video. I’m facing decisions for my 1880 Victorian and helped a lot.

[@BrentHull]

Glad it was helpful! Thanks for watching.

[@LogansRun314]

This is great, thanks Brent. I'm not, at all, a fan of foam either. Thank you for being a big part in properly preserving these old homes!

[@BrentHull]

Glad you enjoyed it! Thanks for watching.

[@pauljavener7342]

I agree with you also. If you ever see what happens to a car where you put spray foam , a person would never ever have it in their house. The water damage is crazy bad.

[@jackpestaner6925]

Thanks for the thoughtful videos Brent. I have a 100 year old brick home, two wythes of brick with furring strips and wood lath plaster walls. For the kitchen and bathrooms, I have stripped down to the brick, and it seems to me the safest option is to re-furr (is that a technical term?) the brick, and hang drywall. I was considering stapling Tyvek over the furring strips to provide some barrier to air movement, essentially establishing a 3/4 inch gap between the Tyvek/drywall and the brick. Any thoughts? Thanks!

[@BrentHull]

I like the air gap idea. I'm not sure tyvek helps. depends where you live. Hot humid client or cold climate. Good luck.

[@jackpestaner6925]

@@BrentHull thanks Brent, its Richmond VA so cold-ish winters and humid summers

[@sergiofernandez3725]

Realy enjoyed this. My opinion is that you should think of the outside of the building as a rain screen. It will get wet with heavy rain and with driving rain it will get in and behind that surface. As good and as water tight as they make it. Nature will do its thing. So behind the rain screen should be a void/air gap at least 50mm which will allow any moisture water to flow. at the buttom of this 50mm gap there needs to be substaial venting to allow the material to dry. Then the next layer into the building can be wood/stone/brick. On the inside of that will go a breathable insulation like rockwool then it plasterboard/sheet rock. This gives you several things. Warmth of the building, Breathable inner wall. Water resistant outter wall with natural drying capability. This must sit ontop of a structure that is damp free or damp resistant which again is vented.

[@BrentHull]

Nice. Thanks for the insight.

[@JosephHuether]

Brent: Just an observation. I live in New England and my family has an early 19th century home farmhouse that my father-in-law had cellulose insulation blown into in the late 1970s. It has held up very well. By no means would I consider it to be a “high performance home”. By and large, being a residence…not a museum, pool, spa…the humidity fluctuates with the seasons. Also, air conditioning is generally not used. Sheathing and siding are wood and there are decent overhangs that help shed bulk rainfall water….the region gets 50-plus inches per year. When we added a small addition in the 90s and removed siding in one area we were impressed to observe that the cellulose hadn’t settled and was nicely and tightly packed. Best of all if there is some short term water vapor (not bulk water” drive the whole assembly wood sheathing and insulation can absorb this as a buffer and dry out in both directions. One downside of a system like this may be that the exposure facing north, when insulated, tends to take a bit longer to dry out when exposed to heavy rainfall and is subject more freeze-thaw. This means it needs to be repainted a bit more often. In general, the paint finish on the siding in this region, especially at a higher altitude, just takes more of a beating and repainting plus selective bevel siding replacement is a fact of life and has been for centuries.

[@BrentHull]

Nice, thanks for sharing. I've been pleasantly surprised on a few jobs where cellulose has been used.

[@twobluestripes]

This is SO INCREDIBLY HELPFUL for those of us who own or have family with old houses! Also I am definitely an anti-foamer in mosts situations, because the application is super bad for the environment unfortunately. I do think it makes sense in unusually shaped buildings that would be super tricky to both seal and cut soft or rigid insulation for- like my dad’s geodesic dome outbuilding that he really should have insulated (a 1970s or 1980s kit, it’s a very large shed). Rockwool is really sustainable, it doesn’t burn easily, it’s affordable, easy for DIY builders to us, and you think it’s effective? Sounds ideal.

[@BrentHull]

Nice. Good luck and thanks for watching.

[@tc9148]

Helping my son remodel his 100 year old home. He gutted first floor down to studs. Air sealed sheathing board cracks with ZIP tape. Insulated with Roxul mineral wool batts. Immediate improvement in comfort and quiet. Agree mineral wool insulation is the best for old homes, never use foam insulation.

[@BrentHull]

Word!

[@mikekim6374]

Hi Brent, I truly appreciate all the wisdom and knowledge you have for historic/ older homes. We have a 1926 home with exterior walls without insulation. We are in the process of completing tearing off the ugly vinyl siding that was put on and putting on new WRB as well as a rain screen (6mm). If this is done, would blowing in insulation be okay in this situation or would you still recommend not to insulate the exterior walls?

[@BrentHull]

It depends. Where are these going or being installed? Is there original wood siding? Are you putting the rain screen on outside? Send me an email at [e-mail] to confirm.

[@tipr8739]

I have an old brick with original timber in the roof. I’m planning on using the Havelock sheeps wool as mold is a concern throughout the northeast here vs the rockwool. Also the air quality is a concern for our kids. That might be a consideration for some of your clients as well.

[@BrentHull]

Yes, I've heard good things about sheep's wool. Keep me posted. I hope it works out.

[@907stovecraft8]

Organic better than inorganic to prevent mold? I don't get it.

[@shaunbava1801]

@@907stovecraft8 that makes no sense, rockwool doesn't mold....like ever.

[@Obtuse94]

Rockwool molds?

[@shaunbava1801]

@@Obtuse94 Rockwool will not mold, you could dunk it in water and shove it in a plastic bag, Rockwool is inorganic it isn't the same as wool it is literally made from rock.

[@ratecoudo]

Those 100 + years old homes don't have insulation but they are beautiful anyway I love them so much thank you for this wonderful video.

[@BrentHull]

Me too.

[@laceymccarthy5983]

I live in an 1870s house in the DC Metro region that is a similar situation to the 1881 example in your video. We are having some work done which involved the contractor opening part of an exterior wall and they say they have to install insulation to pass inspection. I asked for a dimple mat between the insulation and wood siding but they don’t seem interested. Should we remove the insulation after passing inspection or push for an air gap barrier like a dimple mat? What kind of dimple mat do you use? How can we best advocate for our old house?

[@BrentHull]

The goal is an air barrier between the siding and your insulation. You can accomplish this with a dimple matt or with wood cleats that will allow air to move between them. Insulation is good, but you don't want foam.

[@ryananthony4840]

Another great video Brent, thanks!

[@BrentHull]

Glad you enjoyed it!

[@Its_RichieRich]

This is very enlightening. I have a home energy efficiency evaluation for my 1890 home coming up in January and was going to have them do "the works" since I get such a good rebate through the state program. I'm also going to finish my attic and was excited to get the roof insulated by them too. Now I'm second guessing that plan. Is there a safe rule of thumb when considering adding insulation to avoid problems?

[@BrentHull]

Thanks, yes! Insulation is good but it must be installed correctly. I wouldn't shy away from it but I also wouldn't let them blow foam everywhere. Where are you? California or Minnesota? Your region will determine alot as well. Good luck.

[@wolf52eagle]

So glad I found your channel. My plans are to build a simple one bedroom cabin 30 x 24, no loft. It will not have air conditioning and will be heated with wood. The most important thing to me is to enjoy and preserve the natural beauty of the rough hewn lumber exterior and interior. We will be using hemlock and hickory. In your export opinion, should we insulate ( rock wool) or not? My concern is will the untreated lumber be able to air dry if insulated. There are no building codes in my area and It will be off-grid. Thanks for any suggestions you may have.

[@BrentHull]

Yes, your wood construction presents a challenge. I would encourage you to look at the challenges of building a log cabin in the log home industry. I would buy salvaged lumber if possible. Wet would or freshly cut wood will continue to move and dry out for years. That movement will open up all kinds of cracks. Sounds fun, i don't think you need to insulate, the thermal mass of the wood will be enough for the walls. Your connections around doors and windows will need sealing.

[@wolf52eagle]

@@BrentHull thank you. 😊

[@RVIArchitecturalDesignUK]

I work almost exclusively on pre-1940 homes in the UK - we have many millions of them. Understanding the hydrodynamic effects of the materials you are using is critical and we have developed methodologies for insulating (improving thermal envelope performance) of every type of historic wall you can imagine. The palette of materials available now means that all historic structures can be retrofitted for improved thermal performance. All of the situations that @BrentHull illustrates can be easily insulated without detriment to the longevity, aesthetic or stability of the historic structure. Traditional (often biodegradable) materials that could be used include; woodfibre, cork, lime, hemp, foamglass, cellulose, recycled textiles, clay, vermiculite, wool and chalk (calcium silicate). Each retrofit solution is tailored to provide a suitable solution to each building element and their junctions with other elements. Crucially, each material used allows for suitable moisture management whilst improving the thermal performance. Our obsession with petrochemical products as the answer to everything is not our fault as designers, we were led to believe through powerful lobbying mainly, that petrochemical insulation materials were the only solution we needed and through 2-3 generations we have lost touch with our traditional materials to such a degree that they have become 'unconventional'. I still need to use some PIR and polystyrene but have cut my addiction down by c. 80% over last decade. Additionally there are significant health and environmental benefits to choosing natural or inert materials.

[@royordway9157]

I'm in coastal Maine and have been pounding nails for 47 years. I have seen so many old houses, early 1800- 1940 more or less, that the paint is peeling, and the wood is rotting. Every one of them have been modernized with lots of insulation in the walls with no thought given to the fact that basements are wet, the foundations are granite blocks and in a lot of these houses' ledge is exposed so you may have a river in the spring when the snow melts and in the summer from rain. If the back of the exterior walls can't breathe and dry the paint won't stick. Although I am too old to take on a big reno, I love your idea of the dimple board to allow airflow and I'll pass it along.

[@BrentHull]

Thanks for sharing your experience. Also, thanks for your years of service to our craft.

[@jerrodbrown3319]

Thanks for sharing your wisdom, Brent. I have an 1890 Victorian in just the shape that you mentioned with 1888 home. While I understand the dimple mat / Rockwool combination for the balloon framed walls, after the drywall is installed and flooring finished, what would be your recommendations for open attic and under floor insulation? I want to give the house as much longevity as possible while offering the most comfort that I possibly can! Thanks for all you do!

[@BrentHull]

Nice, i would insulate the floor joists under the house and the attic. We are in Texas and because of the heat, we insulate roof rafters and not ceiling joists so that the AC unit in the attic is in a slightly cooler space. Good luck.

[@robinlooney5440]

Have you ever used cork panels on the interior? I've read They are breathable and are a thermal insulator. In Canada they use spray cork on the exterior of homes to seal and insulate. I own a 1949 home complete with plaster walls cork sounds like a great alternative.

[@BrentHull]

Interesting, I do not have any experience with cork, nor have I have seen how it insulates. Let me know if you find any data. Thanks.

[@johnalvitre3154]

This makes great sense. I did insulate a 1910 home I did a full renovation on, but all the siding was replaced with Hardie Cement board Lap Siding over Tyvek and all the windows had z-channel added with flashing to the face of the house before the Hardie siding was added. Now, I am in a historic area, Toledo Ohio and I am looking to do option 2 as you note since I cannot remove the outer siding nor would I want to, it is in great shape. I was looking at a dimpled product used for basement floors to line my stud bays before I fur strip them 2 inches on the perimeter wall. Then, I planned to use rock wool for both R Factor and soundproof capability which I believe exceeds glass batts or other products. But I was also considering cellulose. I was thinking unfaced as I would already have a barrier around the inner bay so I don't want to create a sandwich of vapor barriers. Thoughts? And no spray foam as I hear about the nightmares and I had a bad experience with it too in closed walls. The amount of voids left were so bad, some walls had to be re sheetrocked. Then, I will place drywall on the fur strips of the dimensional 2x4s and finish the surface to a level 5. All new plumbing and electric will go in prior to this obviously. I am happy to hear any thoughts from you guys here. For the attic, I am making it a fun room, but that build will be inside the existing space and will not encroach the venting of the attic from the new build. I am a retired Army Veteran and will do the work myself over some years, so I have time to plan this and update as you may want to throw some knowledge my way. Thank you and thanks for sharing your knowledge, it is the same I came up with for my place, but I do not have the same experience and background as you so I needed a boost in this plan.

[@BrentHull]

I think you have a good plan and understand the issues well. If you are doing Rockwool, you can use an air screen like Cedar breather to create an airgap between back of siding and insulation. You don't need a dimple matt and it would be easier to install. I would not do a paper backing. I also like Cellulose. Good luck.

[@johnalvitre3154]

@@BrentHull Thank you Brent. Love your channel and I am loving the Cedar breather info. Sounds like a plan.

[@annettegarciakerslake8588]

@@BrentHull Just to clarify, the cedar breather is between the siding and rockwool? Does the rockwood but up against the siding and cedar breather, or should there be some space in between?

[@LukePitney1991]

Brent, could you expand on insulating the floor system and benefits you may gain outside of an air barrier? Im in the process of purchasing my wife’s family farmhouse. Historic, 1880’s but built very well by her great, great grandparents. I’ve been in the business for 16 years but this house is going to be the biggest challenge I’ve taken on. I was considering tearing the plaster out of the exterior walls and insulating per room as I remodel but considering leaving them alone as they’ve been this way 140 years and no signs of serious rot anywhere. Would also love to hear your thoughts on shotcreeting the limestone foundation walls to minimize intrusion and add integrity. It’s also a much more cost effective solution then jacking the house and pouring new walls. Love the knowledge you’re sharing!

[@BrentHull]

Well, I would mostly likely approach it with a, "if it ain't broke don't fix it" style, especially as old as it is. Your "fixes" sound destructive. For instance, on the foundation is it shifting or moving? Is it leaking? Are you trying to stabilize it? Just curious why you would consider pouring new walls? Overall, I would approach it carefully. Also, i don't know where this is? North? South? How wet or dry. A lot of factors to consider. We are working on an 1870's house in near Houston and will most likely, NOT, insulate the floors. FYI

[@LukePitney1991]

@@BrentHull Very thankful for your response! I’m honored! This is quite a ways from you, Northwest Illinois. About an hour and a half from Chicago. We do get some brutal winters. Foundation hasn’t shifted from what I’ve seen, there’s minimal water intrusion during wet seasons, but for the most part, mortar and stone are in good shape. Would just like to try and make it less damp, potentially have some usable space as it is a full 8 foot basement. Leaving behind a house I just built three years ago, but somehow it feels right to get connected to the past!

[@evictioncarpentry2628]

I renovated a 1904 house. The exterior siding was already replaced new 8inch textured aluminum. Under that is the original doubled up shiplap with plaster and wood lathe on the interior. When we were running new electrical, every exterior wall we opened up we found blow-in insulation. So at some point, I assume when the siding was done, someone filled up all the walls from the exterior previously. The first winter it sat vacant (keep in mine our winters are minus 30C in canada) I couldn't believe how low the heating bills were for a house of this age but now I know why.

[@BrentHull]

Interesting. Thanks for sharing.

[@architect_talk]

Can you talk more about insulating the 1870’s ceiling using rockwool? Is the roof currently vented, and if not are you planning on venting? I have an 1850’s unvented Philly rowhouse . Trying to figure how to insulate my cathedral ceiling and it seems like the only way is to add rigid to the exterior (if I’m to avoid closed cell spray foam)

[@BrentHull]

Ok, I will soon. Thanks for the suggestion.

[@fazerfaze]

This is really important

[@BrentHull]

Agreed.

[@3tI8P-lj2lo]

It would be great if you could do part 2 talking about how you handle basement/crawl space and attic insulation ... and also sealing (caulking) around windows. I'm dealing with a 1910 brick row house with original windows, a 1920 stuccoed bungalow both with full basements, and an 1870s timber frame on pier and beam. Drafts are an issue all around.

[@BrentHull]

Hmm, ok. Thanks so much.

[@BenJohnsonDotNet]

I'm doing a full-gut renovation of a 1920 house, and this video makes me feel like I'm on the right track. Using rock wool and maintaining a 1/2" air gap between the insulation and sheathing is the strategy I've decided on after a lot of thought and research. I'm furring out the studs to match the thickness of the original plaster, so as long as I don't push the 3.5" rock wool all the way back against the sheathing, I find that the dimple board is unnecessary for me.

[@BrentHull]

Great, keep me posted. I think you've got a good plan. Thanks

[@allie_ella]

Thank you Brent! While trying to preserve my 1832 house, there seems to be hardly any sources for how to do it right without ‘new construction’ solutions. I have to ask though, I am about to get spray foam under the floor in the crawlspace and wondering if I’m making a mistake doing so, I have a pier foundation so encapsulation is crazy $, that and it did have 6mil plastic down but water was pooling and it caused moisture damage that I’ve repaired now. Any information on that? Thank you!

[@BrentHull]

I don't like foam, but if you have to, use closed cell foam. I would use rockwool or blown in cellulose. Good luck.

[@robertbamford8266]

Beyond the potential damage to paint and wood, the health risks of mold and mildew should also be considered. (Just baca use you can, doesn’t mean you should.). Thanks for the video.

[@BrentHull]

Thanks for watching.

[@PurpleMonkeyDishwasher88]

This is reminding me of when contractors would use portland cement in basements or even when repointing brick facades in historic homes instead of the proper lime mortar that was indicative of construction for the time period (since homes back then were built with a more breathable membrane since there wasn't air conditioning). Part of it coming down to some not knowing the difference, and a majority of the time some builders just doing it out of sheer convenience, since lime mortar is not as readily available in most home improvement stores.

[@BrentHull]

Agreed. Thanks so much.

[@stephaniepatel4132]

I appreciate this information. I have the second situation, where you suggested dimple mat and rockwool insulation. Is there a video that shows how to do this. I couldn't find any resource that suggested using dimple mat on interior wall as part of insulation process.

[@BrentHull]

Matt Rising with the Build Show has a video. Thx.

[@christianwright6892]

Love your videos! I’m looking to insulate my 1935 home in East Texas using rock wool as you recommend but am having trouble finding contractors who install it. Any you can recommend in our area?

[@BrentHull]

I would reach out to rockwool. They should have some certified installers. Good luck.

[@ilyoukayxxxx8]

I have a 1918 home. Original siding I do not want to replace and interior walls downstairs are plaster and lathe. I'm leaving it as is. However, upstairs, I have taken down the interior walls back to the studs and the ceiling is open to the joists. New rood being installed soon. I will not insulate the walls upstairs based on your advice. But I do have a couple of questions. Is it ok to put insulation in the walls joist bays at floor level? Does this help or hurt? Before I put in insulation in the ceiling and then finish, is it ok to spray foam the very obvious cracks? What do I do around the windows? Can I use spray foam? Also, in the dormers there are obvious openings everywhere along the sides of the wood siding. Any harm caulking each board before finishing the walls with drywall? Thanks!!

[@BrentHull]

If you put in an air barrier between your insulation and the ext siding, you can put insulation in your upstairs walls. I would recommend a spray can foam to seal all small holes. I would not caulk the siding between laps as you will trap moisture. I would insulate rafters and not ceiling joists. Good luck.

[@lawrencemccoy]

Thank you

[@BrentHull]

Welcome.

[@MandoFettOG]

First house was a 1913 craftsman 4 square in WA. No wall insulation and no rot. Only place I found an issue was a wall that had been opened up to change the windows. And so the city required they fill the cavities with insulation. Low and behold the sheathing boards on the outside had water damage and minor rot.

[@BrentHull]

Word, thanks for that sharing!

[@josephhuether1184]

My family owns a 200-plus year old farm-house in southern Vermont. Painted clapboards on solid wood sheathing and plaster interior. Quaint but architecturally unremarkable. We blew in cellulose in the late 1970s and it has performed very well. No vapor retarder anywhere in the assembly. Walls can dry in either direction. We removed a section of one wall 30 years ago to connect to an addition and the insulation was dry and there was absolutely no settlement whatsoever. Our addition was built to Code with a poly vapor barrier and fiberglass insulation and now there is considerable siding and OSB sheathing rot because, I believe, the siding/sheathing layer could not dry to the interior. Cellulose is great stuff and does function as a moisture sink. Nevertheless, a well insulated building will have cladding that takes longer to dry out in wet climates.

[@BrentHull]

Great insights. I agree. Thanks for sharing.

[@njreno1]

You said it best " sacrifice longevity for short term solutions" . That is the current trend.

[@BrentHull]

Thanks and thanks for watching.

[@MrBaconis]

Also a consideration in colder climates. Insulating basement walls from the inside in an old brick house could cause frost heaving and ruined brick exterior cladding.

[@BrentHull]

Good point. Thanks.

[@danicamills7029]

Love the video. would like some guidance. On our house 1878 Martinsville indiana. Currently has three layers of wood siding problem for us is we live in the woods and the red headed wood peckers love to put holes in the siding so we plan to metal putting siding on after removing all three layers of different aged siding and applying a Georgia pacific weather resistant osb. Then putting polyiso rigid foam on the outside of the osb. Inside the house has drywall with faux wood panels covering that so no real historical value. Would you advise the plan of the osb and rigid foam? We do use central air and heat with wood in the winter.

[@BrentHull]

Hm, that is a hard one. The preservationist and purist in me couldn't do it. I would rather deal with woodpeckers than change to modern materials. My 2 cents.

[@rrtexas6976]

What is the best way to figure out what type of walls you have? My upstairs appears to have Sheetrock covering original shiplap or other board. Not 100% sure I can only see it from a wall socket. I am pretty sure previous owner destroyed almost all historic relevance to the bottom floor. Also if we are doing repairs to the exterior siding is it possible to add the air barrier and blow in rock wool or cellulose? We are going to remove the aluminum siding that is over the original clapboard and assume there will be needed repairs.

[@BrentHull]

That is hard, it will depend on how it was clad. Is the siding over studs? Probably. I would work to insulate from inside, but your call.

[@johnalbertsen3112]

Thanks for that info . I live in New Jersey in a 110 year old house 0 insulation and a ballon frame construction. I want to insulate the rim joists in the basement , i was thinking about using spray foam or just rigid foam board and spray foam around the rigid foam. looks like rigid foam is the way to go.

[@BrentHull]

That or cellulose. Cellulose can be blown in. Rockwood is good as well. Thanks.

[@andrewbenham9869]

I already insulated, and drywalled. I have asphalt siding over the old wood siding. That means I have to take all the siding off the outside of my house, and make it water tight, create an airgap, then use wood siding correct?

[@BrentHull]

Depends on where you live and which climate zone you are in. It also depends on how the asphalt siding (like is this the stuff from the 20's or 30's?) is applied. It might have an air gap between it and the original siding. I would work hard to not have to do that. You could also watch it for a season or two and see if it is creating problems. If you are in a hot dry climate i probably would not change it.

[@rayc3214]

not to be a pest, i have a 1935 uninsulated house with vented crawlspace . if this was your house would you use foam or rockwool to insulate floor? also a good reference book for interior trim farm Victorian thank you for the expert advice.

[@BrentHull]

I would insulate with Rockwool. Anything but foam.

[@mauriciocurbelo0123]

What would you recommend for basement cripple walls or crawlspace walls in an older home? We have an 1895 house (PNW climate) and have been advised to do sprayfoam. The exterior of those walls is cedar shingles. I'm concerned about adding a vapour barrier where there wasn't one before, but everyone seems to recommend spray foam in order to seal the crawlspace and prevent moisture from getting in

[@Dracomancer273]

Mineral Wool. Same climate/area and situation and that's what we are going with at least. If you have a steady moisture problem, it might be a good idea to consider digging a deep (enough, don't go for inches, go for 2+ feet) sump hole and installing a sump pump.

[@BrentHull]

Well as you've seen in my other videos I like sealing the crawlspace and have used closed cell foam in that area. I do that to seal up the crawl spaces often after we have sealed the ground with poly or some material. I'm only sealing the wall to ground connection. It will depend on the amount of moisture in your walls or outside. We are much dryer climate than you and don't have the same moisture issues. If your house is 1895 then I'm assuming a concrete beam wall. In general you need to determine your goals. There is not sense in sealing the walls if you aren't also sealing the ground. my 2 cents.Thanks.

[@mauriciocurbelo0123]

Thanks for the response! Yes we're going to seal the ground in the crawlspace first. The cripple walls are about 2' tall above ground (sitting on top of a 1950s concrete foundation) and are exactly like the 1870s walls in the video: beadboard inside, empty cavity, shingles outside. Hence my hesitation about closed cell foam. But it sounds like it should be ok. On an unrelated note, another insulation method that's common here is blowing in cellulose from the outside by poking holes in the siding. Gives mediocre results and probably not great if the holes aren't patched up perfectly.

[@amyblueskyirl16]

@@mauriciocurbelo0123Plus the cellulose just settles to the bottom over the years in a vertical wall. I’m not going to seal up under the house (also in PNW). Just had a new foundation with cripple wall put in (house is on a slope) to replace the posts on rocks. Going to do the “old-fashioned” thing: vapor barrier on the ground, batt insulation stapled under the floor, will make it warmer but still allow ventilation I figure

[@JSAFIXIT]

I think I may have found a channel ill be referring back to quite a bit. We are lookong into purchasing a house built in 1904. It's been partially restored, but it still has no attic insulation at all. There is a wooden floor up there, with nothing in it, and a very tall peak, about 14 feet from the floor to peak. Heating and cooling are my only concerns with it as it is quite large, 2779 sq/ft on the 1st and second floor with 10 foot ceilings, 9 foot ceilings in the full basement, and of course the full attic. Thats A LOT of cubic feet to heat/cool

[@BrentHull]

Good luck. Sounds like fun.

[@WakandaBabe]

This is my experience, which may be helpful. I have a well built, 1927 bungalow. Original everything in the house. Plaster and lath walls. The house was also built with some steel studs, which I understand is not usual. Original exterior. One story, with full attic, full basement and 9' height walls. My house is small, just 1092 sq ft of living space. I had insulation blown in 11 years ago and, because it settles, wanted new insulation added. BUT, the old insulation was done over knob & tube wiring by a crappy contractor! So, here's what I had done (cut and pasted from another comment): I just had my attic air sealed before I added new cellulose insulation. The process was: All the old insulation was removed. Then an electrical contractor rewired the entire house; all knob and tube wiring was removed, not just deactivated. After the electrical inspection by the city, the insulation guys came back and air sealed the attic. They used foam board and various foams for cracks, etc. I saw pictures of what they did and the amount of work that was done was amazing. They also air sealed my basement in the same manner. Then new insulation was blown into the attic and more insulation was blown into the outer walls of the house. All the insulation work was done by a BPI certified contractor. Then an inspector came with a heat device and checked the heat loss. A few spots in the walls needed to be 'topped off' and that was done. The difference in my house is amazing; no more cold spots! I have a 1927 Craftsman Bungalow so I still have, and intend to keep, all the original windows, so heat loss happens there. I have caulked all the windows. I am working on getting interior storm windows but in the meantime, I put up plastic coverings. Even with the old windows, the house is significantly warmer. What a difference. I have never had a moisture problem in my walls; no peeling, leaks, etc. Last year I had a new roof put on with the proper venting, etc. This may not be the way everyone does it, but I am very happy with the results. Plus, I DIDN'T PAY A DIME FOR ALL THE WIRING/INSULATION/INSPECTION WORK (which is another story!). If you can insulate the attic, I highly recommend doing so.

[@anarabasov1920]

This is an excellent video! I have a quick question about a scenario that is very similar to your 3rd case. We are remodeling a 1920s house (remodeled in the 1950s) in Texas. The exterior is a concrete smear sprayed on the brick in the 1950s. Then there is an air gap followed by tar paper. Then we have shiplap, stud, and shiplap on the interior. The house has no insolation. An "expert" told us not to insulate unless we can re-do the exterior and put a Tyvek vapor barrier. He was worried that the new AC system will cause issues in this scenario unless we put in a propper vapor barrier. After watching your video I now wonder if we can insulate because of the air gap. A true expert opinion would be great.

[@BrentHull]

You can definitely insulated. I would blow in cellulose because it is the least invasive way. They don't have a blown in Rockwool yet, but if you wanted to take off the interior shiplap you can do Rockwool batts. You have an air gap. You should see a big difference. Good luck.

[@anarabasov1920]

Thank you so much for your answer. That's great to hear! Even with a more efficient modern AC?

[@mikeyj894]

Great video, thanks. My 120 year old house has double brick outside walls. I have removed the plaster and lath and I am going to build a 2x4 wall about an inch off the brick and fill it with rockwool. There will be a vapour barrier on the inside, but I am not sure what to put on the outside between the insulation and the air gap. I want something that will hold the rockwool in place, but will also breathe so moisture doesn't get trapped in the wall. Any thoughts?

[@BrentHull]

Masonry can carry a lot of water safely and release it naturally. I'm not sure you need a vapor barrier? What kind are you thinking? I think your solution is fine, depending on your climate. Where do you live? I think your close.

[@carmencolon3520]

No insulation here but for sure will love to do something on the floors. Two rooms floor are super cold in the winter. What about Thermal liner wallpaper on plaster?

[@BrentHull]

I would seal up the basement/crawl space as a first order. I don't have any experience with thermal wallpaper. Sounds interesting.

[@carmencolon3520]

@@BrentHull Yes it does, would you please research on this and share with us the good ,bad and ugly since old houses are your expertise. We are just caretakers of the past and if do take the right steps protecting these house they will have a future.

[@annettegarciakerslake8588]

We have a 1906 balloon structure in Venice, CA. Unfortunately, due to a roof leak, we had to take out about 1/3 of our lath and plaster exterior walls. Would you have a suggestion on what type of drywall to put on the walls facing the exterior? No tar paper; it's just the wood siding.

[@BrentHull]

I would use something like cedar breather for an airgap, then use a cellulose or Rockwool insulation then drywall. Good luck.

[@annettegarciakerslake8588]

@@BrentHull Thank you for taking your response! Your videos have been so helpful.

[@sethhamilton5824]

I’m in Canada. My home is 3 layers of brick, no air gap, with the interior plaster being directly on the brick. So there is little opportunity beyond the roof and foundation for insulation. However, I’ve seen some fairy old retrofits and they seem to be good as long as the roofing and flashing has integrity. I’m going to suggest that foam would be fine in a wood cavity wall as long as there is an exterior air gap (possibly created within the stud cavity before foaming), much like a modern rain screen. Up here, the ability to insulate is the only thing that guarantees these houses remain, especially with the environmental laws coming and the cost of fuel.

[@BrentHull]

Thanks, it sounds like you have a thermal mass that is helping your situation. Also it sound like we are saying the same thing on the wood. The dimple matt is creating the air gap before you insulate. I still don't like foam and would encourage Rockwool or cellulose. My 2 cents.

[@sethhamilton5824]

@@BrentHull I think you are correct on both counts. The thermal mass thing is real, it takes about 3 days of misserably hot or misserably cold our energy consumption really becomes a problem. Is the dimple product the same stuff you would put on the exterior of a foundation for drainage?

[@sethhamilton5824]

@@davewatson5817 very cool process. I've gone back and forth on solutions. I have a lot of original oak trim and base that would require careful removal and refitting if I did something similar. My solution for now was to heat with wood because hardwood is pretty inexpensive at the moment. Heatpumps and our own solar might make it semi-self-sufficient also.

[@cm8174]

Not sure if you'll see this comment, but I've been trying to tackle insulating my old fixer-upper I got recently and it aligns most with the last house you mention here. I am running into an issue where I cannot confirm any sort of air gap behind the exterior brick. A couple places (in corners) I have observed the brick being just about touching the shiplap sheathing, and others there is an air gap about 1/2 inch wide. in one place the mortar has degraded somewhat and pieces have filled the gap near the wall's base. How much of an air gap is needed for airflow behind the brick? should I err on the side of safety and put a dimple mat behind the shiplap anyway? Any thoughts or comments are appreciated. Great Video! very informative and well thought out.

[@BrentHull]

If you have brick, you have an air gap. I would not spend the money to remove and put on a dimple mat. My 2 cents. Good luck.