Foundation Insulation Effectiveness: Basement building science

Pat Huelman, Cold Climate Housing Coordinator with the Univeristy of Minnesota Extension discusses the issuses associated with insulated foundation walls.
Special thanks to Dick Stone and Nordic Home Inspections, Fargo North Dakota for images.

[@loktom4068]

After watching this well presented video, I have to bulldozer my old house.

[@jackspencer8290]

lmao

[@TeslaBoy123]

Ohh not a good news 🤣

[@Redandranger]

I was thinking of burning mine but apparently I have too much water vapor for it to catch fire.

[@Virtual-Media]

Indoor pool might be an option..

[@d.aardent9382]

Hilarious. I thought id get some good ideas on how to fix some problems and finish projects my dad started but never got to finish himself and eight minutes in im thinking well damn, guess i will have to start at the ground and just replace all the entire foundation....and redo the walls and siding....and...hmmm maybe just move away

[@nicevideomancanada]

I learned a lot from this expert. I have been a Framer in Calgary Canada for over 10 years. I am going to take a 3 year course next Fall called Energy Systems Engineering Technologies. Thank you Mr. Expert, Great video.

[@ryanshannon6963]

Did you take that course? How did it work out?

[@24revealer]

@@ryanshannon6963 TV Ontario did a whole series called "R-2000 The Better Built House". If you can find it its well worth watching. This series covered the proper installation of air and vapour barriers that hardly any builders or renovators follow or understand.

[@24revealer]

What I found was that builders would take the course and then get R-2000 certified on one house, and then go back to their old practices claiming their houses were R-2000 compliant. I was trimming one of these houses and the air was blowing right in under the bottom plate of the wall assembly proving they had not sealed the envelope of the house properly.

[@sallyhoward5420]

This is great information for New Construction. It doesn't offer a solution for homes when getting to the exterior is not possible. I guess I too have no choice but to bulldoze my home and start over.

[@markdrysdale6749]

THANK YOU...FINALLY PURE INSIGHT

[@DONALD1951]

I sealed the block wall with concrete sealer. Now I want to add foam board to the walls. This seems ok by watching this. This is just for a 4’ crawl space that doesn’t get wet. 2 exterior walls.

[@edwardcarberry1095]

Something I have always wondered is why not have the perimeter drain down 12" or 18" below the footing ? You might want to have the drain ?? 24" away from the footing so not to weaken the footing? What distance would be a good compromise?

[@markkurtis8637]

Our footer drain is in its own ditch alongside the footer and about 1/2 of it's diameter below the footer bottom and out from the footer about 4", completely filled with clean stone to the top of the footer. Seems this is standard practice for our contractor so, maybe that's a good technique, just not common? Why /how did you pick the dimensions you asked about?

[@49Roadmaster]

This video is 12 years old. Is this still the latest information? If not what is?

[@leverettmark7657]

Two coats of oil base paint inside the joists...? (old school)

[@barberoliv]

very good video

[@joewedge1480]

this is one of the best explanations of the mechanics and difficulties involved with insulating below grade walls in northern climates. well done.

[@siskandar83]

This certainly is one of the better YT videos I watched and learned so much information about proper foundation/slab assembly and "why" one should construct this way. Also having a real-life mock-up with labels, pointing and demonstrating helps a ton!! Very well done sir!

[@curtwichman3956]

That’s fine for a new build but what about a remodeling of your basement

[@kevinhornbuckle]

This is the most thorough-going, understandable presentation on foundation moisture management that I've ever seen. The information here could save you tens of thousands of dollars.

[@mrvv8337]

More likely save the next owner tens of thousands of dollars.

[@goaheadmakeourdayscooterpe6724]

Very informative and you saved me a pile of money, I was thinking of finishing the basement but after seeing how it's nearly impossible to do without problems I said forget it.

[@dlg5485]

Excellent information! I am just beginning to plan my future home build here in Ohio and after reading 100s of articles and watching 100s of videos on building science strategies, I've learned that the most important thing to get right, by far, are the 4 envelope control layers (water, vapor, air, thermal). If you spend an appropriate amount of the budget on getting the envelope right, you will absolutely prevent problems down the road AND get a more comfortable house, overall. I've decided to go all out with my envelope and try to save some money on aesthetics, which can always be upgraded later. It's the structural details that should never be overlooked during initial construction because they're not easy to fix later.

[@Patriot4TheTree]

I'm not trying to be a dick, but as a home owner, when the fuck are they going to start building houses properly the first time around?? I have been hearing about "problems" for the last 40 years that involve HUGE projects with HUGE cost, with a million little specialty companies out there, just waiting to take your money to fix your specific problem, that SHOULD have been done right when it was built. Builders, contractors and developers in this country, really should be ashamed of themselves.

[@jacke1129]

No you're exactly right. The entire industry continues to ignore these basic laws of science because 1) it's not the way they've been doing things, and 2) it adds cost. Builders, contractors, developers...they're all in the same boat and put 99.9% of their efforts towards the shiny objects that people want. Wood floors, granite countertops, curb appeal, etc., are what everyone's been trained to focus on. Never mind your house has shitty engineering and that your basement will be growing mold before you even sign the closing papers. It all comes down to $ and because doing things the right way cost more the industry instead keeps throwing granite countertops in your face.

[@TheStudio2020]

PROFESSOR, THANK YOU FOR GIVING US THE GIFT OF YOUR KNOWLEDGE AND TIME!

[@cindybarber8449]

Thanks so much, i need to show this to the builder doing my addition w/ crawlspace.

[@jasonmaddison9700]

Outstanding video! I've now decided to build my house on stilts.

[@jvkew]

The best explanation of insulation issues I've ever seen. Thank you.

[@carolynm1625]

Great video to educate people in the construction business as well as homeowners. It's often hard to sell clients on proper building methods to prevent potential issues like mold to develop in sealed tight homes. ICF seems to be a good alternative method to constructing a basement.

[@davidchristian6057]

This video should be required reading/viewing for anyone buying a home with a basement or building a new home with a basement. The very best in depth analysis I have seen.

[@CMCraftsman]

It’s actually not relevant anymore

[@49Roadmaster]

@@CMCraftsman Just finished watching this video and wonder if it was still relevant anymore. Where are you getting the latest and greatest information?

[@mpxz999]

Most informative insulating video I've had the pleasure of finding yet!

[@ml9633]

Wow Pat, this is the best video explanation I've found, and I'm 65, so I've seen many. Thank you Sir for sharing this knowledge of yours so simply & understanding to us. The enigma is over... Cheers :)

[@uncertainscientist]

This is a fantastic video. As a first time home buyer trying to understand the fundamentals of building science so I can better choose a home, this is invaluable. Thank you for taking the time to put this together!

[@allalphazerobeta8643]

One thing to keep in mind is that if you insulate a concrete basement or even slab on grade from the outside. You are giving the house a huge thermal mass. An other way say thermal mass is a thermal reservoir because it is a mass that stores hot or cold. This thermal reservoir will make a huge difference in emergence situation where the house looses heating. The warm "indoor" concrete in the basement will keep the home warm probably for several days if not a week even with extreme conditions outside if the house is properly insulated.

[@nickdannunzio7683]

I agree... did project where the engineer had no insulation under the basement floor slab (just a really good moisture barrier) he claimed that the earth under the slab becomes part of that thermal mass as you explained...

[@pampierce]

Excellent! Just wish you showed exterior insulation using other products like mineral wool, or graphite polystyrene. Keep in mind that foam products make great nesting material for insects, even below grade. I've seen insects in foam in northern Michigan, it is not just a hot/warm climate issue. Thanks for the excellent videos on the subject of below-grade insulation.

[@MISSY4EVR]

Yes my foam has holes in it and the parging fell off

[@allengazette8739]

Great video, thank you for the education. I have learned so much more here in 30 minutes than all my discussions with contractors and building suppliers! Best regards.

[@Muirtty]

Form-a-drain footing and ICF with membrane barrier.

[@vanessap8717]

Great video, thanks for sharing:) I'm curious as to what you would recommend as the best insulation and install if you had no choice but to insulate a basement from the inside?

[@republitarian484]

Sounds like you shouldn't use insulation on the interior. It's below grade anyway so it already is insulated to a certain degree.

[@percyfaith11]

Have a contractor dig down to the footings on the outside and water proof and insulate. Expensive? Yup, but it's the best way.

[@MaverickandStuff]

For the exterior looks, there is rigid foam with a stone veneer that can be used where it may be exposed.

[@stanleysiewierski]

The overall point is to make sure your basement wall and floor have been properly waterproofed/damp proofed from the outside. After this is done insulate from inside, especially top portion of concrete wall where it is exposed to cold air. (North climate). A dehumidifier is a good to have too.

[@johnwhite2576]

Umm no , he makes it. Rey clear you insulate from the OUTSIDE!!!

[@vz07mk]

Thank you for that video. I'm assuming that on existing homes where the outside has not been insulated, that you are left with no other choice than to insulate, and vapor barrier the inside foundation wall ? ...or would you still leave it alone and take the heat loss in exchange for risk aversion to moisture buildup ?

[@austinbirt7613]

Ive watched tons of videos on insulating and framing basement walls. This is the first that makes it truly understandable and its a very in depth video. Thanks!

[@vilo3454]

All this stuff sounds so great but NOBODY is building homes doing any of this stuff so with all the stuff you mentioned although nice...its like a zillion dollars to do after the fact on the outside of the home and also impossible to do almost before the fact unless you are the actual builder or on site everyday watching the half assers build yr ish .....so its like thanks but uhhh what am i going to do about it now??????..........but thanks for the ideas and info

[@PaxsonWoelber]

I'm owner-building my first home in Anchorage, Alaska. This is by far the most helpful video I've found on how to build an effective cold-climate foundation. Thanks a ton for the work in putting this together.

[@mikesvirk4217]

Hi Paxson! How did the build go and did you insulate from the outside!?? I'm wanting to build in northern Ontario and looking to build foundation and walls of bungalow with block. No lumber but the floor and roof Your feedback and experience would be a huge plus. Thanks! Mike

[@PaxsonWoelber]

5 inches of XPS on the exterior, over a layer of Ames Bluemax. I’m sure it will work nicely if I ever finish the house…

[@mikesvirk4217]

@@PaxsonWoelber Thanks for the insight. Not familiar with the layer of Ames but I'll look into it. Thanks again!!

[@mattmag3089]

@@PaxsonWoelber how's the house? I'm a carpenter building my own finally here in Michigan

[@PaxsonWoelber]

@@mattmag3089 the project was disastrous, unfortunately. The GC I hired to frame the house did such a bad job we ended up having to tear the house down. The project is in limbo and I'm renting now.

[@TommyBoy7Heads]

Absolutely enlightening explanation. Many thanks to Pat Huelman and the rest of the folks involved in the production of this valuable content.

[@AJourneyOfYourSoul]

So basically, older homes with no insulation on the outside concrete basement wall have no good choices.

[@ambilaevus7607]

I am sad to say your probably correct. My house was built in the 60's and I'm pretty sure there's no tar paper or other barrier between my rim joist and the foundation. My dirt floor crawl space is almost a pandora's box on how to address without future issues...

[@dallasbeus2117]

@@ambilaevus7607 Ditto.

[@TheKvlou]

Pff, older homes!?! You’d be lucky to find a modern day builder that’s gonna put this kind of detail into something like the basement foundation. They don’t give a damn, it’ll last a couple years with no mold, by then they’re gone.

[@Bart-dg6qv]

Sell it and build a new one with exterior insulation. If only you can find someone who know how to do it...

[@JSLEnterprises]

spray foam in the summer, keep your basement windows open for a bit.

[@IppiopaidFEEDBACK]

Usually I’m really happy after learning, but this just made me depressed! It’s like my whole life has been a lie, and I’ve been insulated wrong. And all of those inspectors should be fired for saying your okay to install the drywall.

[@jonmkohler]

This is one of the best videos for the fundamentals of understanding what the heck is going on with insulation in a building I’ve seen. Solid recommend, 10/10 almost certainly will watch this again. Thank you for making this content available!

[@Aezelll]

The real moral of the story here is that you basically cannot safely insulate a basement from the inside in any manner using any materials if your sill plate is not separated from your foundation by a capillary break. All methods(fiberglass + plastic, XPS taped and caulked, or a full spray foam job), WILL drive the moisture into your sill and rim joist because they prevent inward drying. Either you seal off that sill from your concrete foundation or it is no deal of any kind.

[@paulmryglod4802]

Aezelll I was thinking that, then saw your comment. idk what to do about it now.

[@TerryPullen]

I would measure moisture content in the concrete and act accordingly. If moisture content is low and there is plenty of opportunity to dry to the outside I would go ahead with interior insulation. If moisture content is high and little opportunity to dry to the outside then any interior wall system would have to be well ventilated to allow drying to the interior.

[@robertjackson4121]

rain we get 100" rain and 30" fog with high humidity. Must drain water from house . French drain inside and outside. Moisture mat on outside wall to drain to daylight . In South must have bug inspection prior to sale or recommended to homeowner. Critter prevention moisture removal inside and out. What do you think of foam block inside and out ?

[@newguy6935]

Hello Pat and thank you for one of the most informative videos on this subject. Question: Though I have no water issues in my below-grade block walls, I still applied UGL's Drylock Waterproofer to the walls as an added measure. Next, I built a stud wall, keeping the studs about 1/2" from the block wall, and insulated with unfaced fiberglass insulation. Then I applied Certainteed's "Membrain" to the inside of the stud wall. The Membrain repels vapor from the inside of the basement (keeping vapor from getting into the insulation) and allows vapor in the insulation (if any) to permeate inward to the inside of the basement. 1/2" Water/Mold Resistant drywall was used as the inside finished wall. Aside from your concerns about a water event that could soak the drywall or fiberglass insulation (though possible, is not likely in my case as I have pretty good drainage in the basement), do you feel that what I've done is adequate? I should also add the I have added two intake vents to the basement that draw air to the heating and cooling system. There were no intake vents there before and the basement only had a very small area of mold growth behind a large cabinet placed next to the wall. Thanks, Steve

[@skiprope536]

All this bullshit called building science. As a professional remodel contractor in the Northeast USA i laugh every time I see these youtube Building Science (=BS Session.) We have demo'd basements from 60 years plus..finished. 2 x3 Walls 1/2 drywall on bare concrete/poured foundation. No mold or moisture in walls or studs or drywall...top to bottom. Out side foundation down to bottom..back then no drainage tiles. NO WATER PROOFING ON EXTERIOR. Drain system put in the 1960's interior. Floor ontop of tile on cement..2 x 4 -5/8 ply and wall to wall. Room size of finished 24x26. Carpet area moisture due to no vapor barrier/plastic under 2x4 sub. New interior Perimeter Drain system to sump. Delta MS Mat on wall/foundation down to below foundation wall. Poured concrete over new drain system. 4" Drain Solid PVD holes on bottom sides. Any moisture on concrete is trapped by mat down to drain tiles. IF at all. 2x4 Framing insulation vapor barrier out. R-15. Plastic 12Mill on floor 2 x 3 Floor joists (like a framed wall laid down) 5/8 Ply...and Finish laminate flooring. I forgot to mention on the demo we reused all the ply that was down from 1987 to 2012 that was down for 25 years no mold or smell. Keep a fan running..dehumidifier and you are good to go. Building Science I think not.

[@dangal9366]

Just bought a 1960 house with an unfinished basement. Cement block foundation, no french drains and no subpump and dirt floor.. Trying to figure out what are my priorities in the basement with a limited budget. My main concerns are humidity, mold, heat cost and radon. I have to say, watching hours and hours of youtube videos has done nothing to help me. Actually confused me even more. The internet is nothing more then a bunch of conflicting information.

[@72strand]

Hmm, dig out the floor dirt. Then a thick layer of concrete insulation then concrete over that.Dig round the house outside. plastic mat with nipples so it drains between wall and plastic, then outside "ground insulation". Re fill dirt. Inside basement steel studds for walls. Make air gap between concrete wall and inside wall. Put a hole near the floor and active ventilation at the to far from the vent hole. Insulate Rock Wool. Plastic, the double gypsum. Only use one plastic layer in the wall. You need some open thing to hold the rock wool sheets.

[@jfgreen1959]

Radon is the biggest scam in building. Search for a KZbin video from a guy who uses the governments own studies and words which are - “you would have to live in a mine, work in a mine, and smoke for radon to be harmful.”

[@marksebby2955]

@@72strand Do all that "on a limited budget"?

[@72strand]

@@marksebby2955 Mostly work. If you put in insulation, you save money needing less concrete. You can dig drain around house with a shovel. I have seen it.

[@Redandranger]

@@72strand "I've seen it" ..... I won't take your suggestions until you've done it. Yourself. By hand. Retrofit of existing home with porches/decks attached to house. Then tell us how it is.

[@kichigaisensei]

Great video. I'd like to suggest that a basement wall with insulating batts should employ rock wool instead of fiberglass. Rock wool is hydrophobic. It will not absorb or hold water even if exposed to liquid water. So, in the event of a flood or plumbing disaster, it would not have to be dried out. Perhaps the wood wall construction would need a little drying. Your drywall will be cashed and need to be removed anyway. Rock wool will also inhibit mold growth due to its inability to hold water. What opinions do you have about products that supposedly "seal" concrete such as RadonSeal?

[@cygnus1965]

Rock absorbs water like a sponge. Once wet has no insulation factor. Blue or pink board is the best bet or a closed cell spray foam.

[@cygnus1965]

Rock wool

[@nidusa1]

I'm concerned about how flammable foam is and other insulation products demonstrated. has this system been tested for what happens when there is a fire. Just look at the London fire. Why can't something like Rock wool products be used instead of foam & plastic sheeting? I would love to see alternatives that also are tested systems for reduced flammability for residential and commercial apt. buildings. there is drywall on inside walls and ceilings to slow fire coming in, but you are still trapped in house inhaling smoke/ carbon monoxide. What if you have a 3 floor residential house and all that outside foam goes up in flames (like London fire) and people just can't get out because entire outside of the house is on fire. they would be forced to jump out of high windows. These are simply questions I'm interested in adding to the discussion to see if there are other methods that could be considered.

[@DeDraconis]

This is a great video. Admittedly, the more I learn about basements, the more I lean towards: "I think when I build, that I don't want a basement."

[@Kobe29261]

Basements are fantastic though - for all kinds of reasons including a nuclear bunker! lol! I want a basement but man its stupid expensive to build properly and for the long haul.

[@patty109109]

I get it but the thing is if you need frost protection a basement is ideal and the cheapest way to expand livable building space. I’ve had a few houses with basements and they’ve done well.

[@DeDraconis]

@@patty109109 I happen to live in an area where flooding is an issue even for above ground dwellings. And also it freezes. Maybe I need to move lol.

[@Neverine78]

Nice video, so what is someone with an older home to do? Is exterior insulation and waterproofing the only and best answer? It seems like and expensive proposition. Are there other alternatives that are effective?

[@donready119]

Interior spray foam works. Some caveats: most need to be covered for fire protection. In a very cold climate, the foundations will freeze and if full of moisture, can heave and crack.

[@hj8607]

IF YOU HAVE A QUESTION, don't post it here. (NO ONE IS HOME)

[@preparedchipmunk]

Very informative and extremely well done. Thank you.

[@trickyrick8621]

ICF while not perfect, would solve many of these issues......

[@DeeInTheHouse]

Great presentation, learn a lot ! ...quite depressing thou if trying to make a dry, moisture free, thus mold free basement walls :) ...also, sounds like you can not have anything on the basement floor :)

[@TerryPullen]

If you already have a damp basement and only want to dry it out first clean up the basement (IE no stuff leaning against the walls) and run an osculating fan 24/7. If you want to dry it out and put up drywall then you need to address water infiltration first.

[@rusosure7]

When one thinks about it, when you're in the frozen North, you don't eat your winter parka. The parka works best on the OUTSIDE. And I think I read where Mt Everest climbers learned to put vapor barriers on the INSIDE of their sleeping bags to prevent their moisture from freezing halfway out. Always place the vapor barrier on the side with the greatest vapor pressure. This video is great at explaining the best way to insulate a home in the Northern states. Best done on new construction though...

[@hansvonschlader8227]

I am guessing that the styrofoam panals all sealed would be good on the outside foundation?

[@jram8555]

What about building basement walls a couple of inches off of foundation concrete wall, using metal studs, and then using rigid foam boards, in the stud cavities, on all exterior walls. I’d pay you, or anybody for a response to my question. LOL.

[@pirihern9329]

1942 cape in hamden, ct. Just doing closed cell between crawlspace cedarblock and floor joists, then spray foam around corners.

[@johnjacobjinglehimerschmid3555]

At around 6:39 you speak of moving the rim joist assembly inboard and continuing the exterior insulation / vapor barrier up over the rim joist? 1. Isn't rim joist above grade? 2. Are you saying to bring the exterior insulation up higher and then sheath underneath the above grade exterior sheathing? 3. If so ... how do you protect the foundation's exterior insulation/vapor barrier from grade to where the sheathing would typically go. You don't want your sheathing touching the ground. I'm just not seeing how you can bring that exterior stuff above grade and keep it protected from bumps, folding, and mutilation that exterior surfaces experience. Do like the vid tho .... Will be subscribing.

[@salimufari]

This feels like the presentation for ICF foundation systems. Checking most if not all of the boxes when paired with a perc outer wall treatment & slab assembly.

[@ak420dave7]

icf ftw

[@CougarLand]

This is probably the most important videos on this topic Everyone should have to watch this first before watching all those crazy ideas out there. The one slip I heard was when he used the word Polyiso,(26:32) which I would not recommend on a wall as it can become a vapor trap for moisture.

[@genes.1999]

Facts can be hard to accept. You can't ignore physics. Summary of this video: if you live in the north/Midwest and you're building a new house, insulate and manage water infiltration on the exterior of the foundation. If you have an older house, you're screwed, not much you can do (without inviting risk). Maybe just insulate minimally with rigid. You'll just end up turning your basement into a soggy mess. Discouraging. Viewers, keep in mind that these details vary considerably based on what climate zone you're in. Maybe just best not to have a basement at all!

[@trentdinsdale3920]

Sir. I can't thank you enough. Just perfect you and your colleagues well done! Answers to questions I didn't quite have yet. Everyone needs to see this first!

[@JoseGonzalas]

I've been looking for this video and this information for some time. Thank you👍

[@MJorgy5]

Excellent tutorial and model! I have 3.5 questions for the speaker. First, What product or type of insulator is best suited for the exterior of the foundation wall below grade? Also, is a secondary protective layer recommended to the outboard side of that insulation layer? Secondly, in regard to the V-groove style footing shown- is the rebar grid within the foundation wall to be isolated from the footing (due to the waterproofing applied to the top of the footing)? Third, If ICF systems are being utilized below-grade, what precautions might the builder use to prevent the exterior polystyrene layer from being compromised from a puncture/moisture infiltration perspective? Thanks again!

[@NDSUExtension]

Hi! Here is what University of Minnesota Extension specialist Pat Huelman had to say about your questions "I am generally most comfortable with XPS (extruded polystyrene), but semi-rigid fiberglass boards can work, too. If there is true waterproofing behind the insulation and good vertical drainage in front, a secondary layer shouldn't be necessary. It is OK to use rebar to pin the foundation to the footing (rather than a keyway) just work the liquid applied capillary break around the pin. If an ICF is used, it still requires an exterior water control layer (generally a foam compatible waterproofing membrane). This can provide some protection from physical damage, too. Hope this helps"

[@laurijorgenson6683]

I thought this was really well done and super informative. Thank you very much for the education.

[@deeremeyer1749]

"In the summer "heat loss" is in." Hmm. Heat moves from "hot" to "cold". Below the "frost line" soil temps are pretty much consistent and constant around 50 degrees year-round. Your "heat loss" to that relatively "warm" soil (relative to say...air temps outside in the winter months" is more dependent on interior insulation than exterior "foundation insulation". Simple studded/framed interior walls, fiberglass insulation and quality sheetrock is good enough to be called "excellent" and if you use a radiant non-forced air heat source such as electric baseboard heating and have a good quality indoor/outdoor carpet over a quality thin foam backing, once the basement is "warm" it will stay that way. The various "air-gaps" between the warm basement air and the "cold" and dry soil outside the walls are the real "insulation". Warm walls and slabs also expand to "seal" well and moisture is much less of an issue with a "tight" finished and well-insulated basement because what heat loss does occur tends to "carry" moisture with it. Warmer air is less dense but contains more "energy" than cold, dry dirt. Eventually walls dry out, the soil outside the walls dries out and you don't have a saturated soil profile right next to the wall. And GUTTERS and DOWNSPOUTS that take water at least 2-3 feet from the foundation work WONDERS. After a few years with a warm in the winter, cool in the summer (heat is "lost" OUTWARD in the summer from the relatively warm inside air to that "cold" dirt - heat always moves toward cold. Always) dry, tight and "stable" basement, the only thing you need to worry about "flooding" the basement or even "penetrating" the walls/floors/slab-wall gaps with "vapor" is a garden hose connected to an outdoor faucet being left on.

[@markc4166]

wow! And I thought air conditioning was complicated!

[@oBseSsIoNPC]

One thing I am not too sure about, but favor over any of these FINAL solutions is. Why not just space the interior wall away from the concrete, say 3 inches and leave an air gap. Have a vapor barrier on the dry wall side only. When we dress with clothing, air is the best insulator....does this not work well enough on a house? At least any kind of moisture present can circulate behind the insulation and dry up eventually.

[@jonathanscholl6035]

I️ like the detail of the discussion here but if I️ am not mistaken there is NO WAY to insulate a basement from within which is not risky....am I️ right? The reality for us contractors is that we almost never know what the exterior foundation really looks like so I️ would always assume it’s been done poorly. Given that as a starting point....what is the solution for a client that wants a insulated basement with finished walls??

[@garygrunauer734]

2.0 LB. closed cell spray foam insulation, 2" does well in most applications all around the Box Sill, Top Plate and wall. It is the only FEMA approved basement insulation for flood areas. Paint the foam afterward with any interior latex paint, glossy white will reflect more light for a brighter basement.

[@bradley3549]

Having done some substantial research and thinking on this very subject, my solution is gong to be installing a dimpled membrane on the interior walls AND floor, with an interior perimeter drain to a sump, and foam board interior to the membrane on both floor and walls. This solves a lot of the issues you might expect to see. The trick is that you really just can't prevent the water from coming in - so instead plan for it coming in and direct it safely.

[@marksebby2955]

@@garygrunauer734 Termites?

[@johngritman4840]

Thank you for this video. My house was built about 17 years ago; I have owned it just 2 years. I was going to finish the basement but ran out of money since I totally renovated the upper floors. Instead I applied DryLok Extreme - 2 coats covered by SW reflective white paint. The walls were reinforced poured concrete with a brick pattern on both sides. If anybody is thinking of this - use Thro Seal and save your shoulder. Both are "pulled into the concrete" and virtually impossible to roll due to the brick pattern. The floors were painted with two coats of SW concrete paint. NO dampness, not cold? I dug around the foundation and found the builder had tarred the foundation, covered it with a mesh, a second coat of tar and then applied 4" of rigid foam insulation. A Swiffer is all you need to maintain the basement. After this video I understand why the contractor put that insulation on the OUTSIDE. I don't have to think twice about off-gassing.

[@nc3826]

I intuitively knew that placing the insulation outside was a much better option but when my parents had their house built they did what the builder recommended and placed it on the inside house. And I inherited the house. This video post just reminded about the costly mistakes made building it, As side note I would use Aerated Concrete (it just has so many advantages and only a few disadvantages) and use a robust vapor/moisture barrier system if I would ever have a house built at this point, But since megatition is the only option for this house. My choice will probably be the less costly and less effective interior megatition option since digging around the whole house seem like it will be to costly for moderate moisture issue that I have experienced. Good luck finishing ur project too. So it goes to prove the old expression is correct "an ounce of prevention is worth a pound of cure"

[@auktober]

Excellent video. The building science approach will always trump the "in my experience" approach.

[@Order-in-Chaos]

Great video. Pat touched on so many issues but was superficial on some critical parts of the waterproofing system. From over 20 years of experience I can add that the most important part of the waterproofing system is the exterior drain tile. 99% of all drain tile installation on new construction are done pretty quickly with almost no effort to paying attention to making sure the tile is completely clean of any foreign matter. You can waterproof using the Ferrari of systems but if you have a clogged or obstructed tile system water can and will go through; it's not a boat. Also I think the worst method of waterproofing a basement from the interior is to use spray foam (closed or open cell). The reason for that is that moisture is standing on the outer side of the foam waiting to infiltrate and has no way of trickling in any direction because it's essentially glued to the concrete. Concrete can and will crack in turn cracking the insulation with it since it's glued to it. Now you have a huge problem because you have a channel of water infiltrating all the water from all sides. I've seen it it's not theory it's experience. NEVER use foam. Basically the best system is the driest system. Follow gravity and concentrate on the bottom part. Drain tile, sump system, a good pump kit will give you a comfortable basement even with minimal bells and whistles. Again it's a great video thank you for posting it.

[@markdrysdale6749]

your thinking is compartmentalized...your experience simply sheds light on improper installation and techniques from construction jokers...no disrespect

[@Order-in-Chaos]

mark drysdale I'm sure you'd be the historical reference on the marvels of Aristotele, Leonardo da Vinci, Michelangelo and the likes. We're eternally grateful for your precious thinking and input.

[@johngritman4840]

There is some good "stuff" which looks like a dimpled fabric that is put over the tarred foundation and goes down to the drain tile. The drain tile is covered with a silt cloth and in my prior house has a clean-out at ground level so I can get a hose in there to wash out the silt - which I never had to do. My downspouts all fed into a 6" schedule 40 rigid pipe that ran to light about 40" from the house. This house has some of the same features but the external drain runs to the storm sewer. I also have 3 sump pumps: 1) a grinder pump so I can add a toilet down there if I want; 2) a regular sump pump and 3) a water powered back-up sump pump. I sealed all the sump pumps because there is radon in the soil around here and while I don't have a problem I just wanted the protection. If you have enough space, burying the "horizontal" pipe that collects the gutter water is the best solution. My basement is not damp, cold or musty.

[@rickrudd]

I have a 100 year old house with quadruple wythe brick walls in the former coal cellar Basement but a poured foundation and no drain tiles. I couldn't get to the exterior wall without digging up my neighbors entire yard. I parged the imside walls of the one leaky side (wasnt that leaky) of the Basement, glued up foil faced polyiso on all 4 walls from floor to rim joist using like 50 tubes of PL Foam adhesive, which has no initial grab, but is great after a week (literally a week). Then furred that out with PT 1×4 16"OC vertical, then Horizontal. Drywalled with greenboard and tiled the floor. I'm slow as molasses and had a kid in the middle. Took me 2 years to finish (did a bunch of electrical and plumbing upgrades in middle plus jackhammered floor and poured piers with which I jacked up kitchen on lally columns), ANYWAY 5 years afterward - Amazingly - no water. No moisture problems. Split it into two rooms: office and laundry room. Polished a HUGE TURD and has worked out well for us. People thought I was crazy.

[@xavspeedy]

Finally a great video on basement insulation! thank you for sharing this, very informative!

[@jefflesauvage967]

I'm currently in the process of applying an interior insulation strategy in my basement (located in the Northeast). Applying the insulation to the exterior would have been too costly, so I'm going with the next best thing. The strategy I've taken so far is to use Rigid XPS on the interior foundation block walls (taped at all seams) and have applied spray foam insulation to the rim joist cavities. The basement also has an interior drain system, with a gap between the foundation wall and slab to allow any moisture to drop down into the drain and ultimately get pumped out. After watching your video, I have a few questions that I hope you can help me out with: 1) The interior drain has a plastic, ribbed sheet that comes about 3" up out of the gap between the slab and foundation wall. I've been tucking the rigid board into this sheet and gluing the boards with vertical strips of adhesive so that any water potentially making its way between the foundation wall and XPS can drip downward into the drain, and ultimately get pumped out. However, I have not been sealing the bottom of the rigid board where it gets tucked into this plastic sheet. Should I put a bead of spray foam along this joint to air seal that area? and; 2) I have not yet applied any insulation to the top of the foundation wall - the XPS ends at the height of the wall and the spray foam was applied at about 2" thick to the rim joist cavity. So, there is exposed concrete block still at the top of the foundation, and part of the mudsill is also exposed. As you mentioned in your video, spray foamers usually seal that area up too making a continuous seal all the way down the wall, but based upon your video I'm starting to think it might be better to leave that area exposed and uncovered. Wouldn't that better allow any moisture moving upward through the wall to escape and dry to the inside, thus reducing the chance of moisture buildup in the rim joist assembly -- most notably moisture that could otherwise accumulate between the mudsill and foundation with nowhere to dry? There is no capillary break between the mudsill and the foundation wall, and adding one is cost prohibitive. On the flip side, leaving that area uncovered might also promote moisture in the warm interior air to condense on that exposed, cold surface thus creating a moisture issue and potential rot on the sill. This is one question that I've been particularly struggling with as I'm near to closing up the framing down there and want ot make sure I take the proper approach. What do you think -- leave the foundation top open or close it up with some more spray foam or XPS? Thanks in advance, and thank again for the great video.

[@jefflesauvage967]

Also note that the interior drainage system has holes drilled thru the foundation wall just below the top-slab level, which sit behind that ribbed plastic sheet. I assume these help any water in the wall to escape down into the drain and get pumped out, rather than accumulating in the wall. Given the drainage system in place, I am also assuming that the foundation wall should be fairly dry and thus would allow me to insulate the interior walls safely.

[@uncertainscientist]

Jeff LeSauvage I'm curious about this -- is it common practice to have holes drilled into the foundation wall blocks to drain any accumulating water down to a interior perimeter drain tile system? It seems like a good idea, and I wonder if that would allow you to increase the insulation on the interior of the space because water that would form there would condense and fall to the system maybe?

[@patty109109]

@@uncertainscientistmy last house the very bottom course had some mortar missing between the CMUs to support this kind of water movement.

[@DaveIngle1]

Wish I would have found this 3 years ago BEFORE I built a new cabin in Northern Wisconsin. This video is at least 10 years old, why isn't this more common info by now and hasn't been adopted / required by the building practices. I insulated inside with 1" foil faced placed tight to the foundation wall, foil side facing in. Taped all seams. Then built my 2x4 framed wall and added 2" foam sheets to the wall cavity. Hindsight, I would have placed both 1" and 2" behind the wall framing to make running electric easier. I would have only lost a total of 4" in overall length and width of the basement, been able to attach full sheets of insulation. Great information... maybe next build... if I ever do.

[@raym555]

well that educated me

[@pjmtts]

My house is ashamed of itself

[@nc3826]

Great video even if I intuitively assumed most of what u said was the case. It's good to have confirmation my assumptions were correct. And the importance of a vapor barrier between foundation or basement wall and the rim joist was not even a consideration, So that was very enlightening. But I hope u have or will have videos on Aircrete or ACC (Autoclaved Aerated Concrete) or any related building material since it seems to have so many advantages vs its disadvantages. For a building material developed in the 1920s its a shame its taking so long to be used on wide scale. And the fact its still not used that widely used in the US is real shame

[@beyhancagritrock3189]

TERRIFIC. Thanks so much for the explanation. Do you have any more?

[@MrStaark]

From watching this is sounds like I have no chance at making my basement actually dry... so... i'm down there right now trying to figure out how i want to give it a finish look..... we have a sub pump.. its never gotten water down there... overall the dehumidifier keeps it nice and dry.... i guess just drywall right against the concrete? and if the mold resistant dry wall starts gettin water dmg, i'll just take it down easily 12$ replace..

[@ds2669]

LOL...my thoughts almost exactly. Kind of discouraging. I was thinking just put the wall framing a little bit (maybe an inch) off of the concrete wall (using blue board), and then just putting up the mildew resistant sheet rock.This way there is plenty of air space between the concrete and building materials to prevent a "diaper" effect. Looks like we'll pay in the end with a higher heating bill :(

[@pepeman3099]

Dane Stewart why not spray foam?

[@ginofoogle6944]

Why not jus use a blow torch and asphalt layered roof sheeting on the outside of the concrete? Not cost effective? otherwise i don't see why not..

[@kingerydev]

What about termite inspection in those areas that have insect issues? Great video.

[@studdruppo]

I've heard that Termites and Carpenter Ants like foam insulation.

[@victorl.6128]

Very well explained, I now know better on what to do with my foundation. Cheers.

[@MrJohnboyofsj]

Yes a house completely foam board insulated and made air and water tight everywhere on the outside is the ideal home. All new construction should use this technique.

[@peropaunovich876]

I am finishing my basement and all walls are below grade. i put 6 mil poly going all the way aound tthe walls on the inside and then fiberglass insulation un faced. Is that going to be good enough or do i need to put more plastci over the studs and insulation

[@dekonfrost7]

@6:30 where is the deck plate insulation? And why are they sold mostly 6" wide rather than 10"?

[@lookimmune2315]

It’s really nice to hear from someone who knows what they’re talking about for a change!

[@scottfurlong5475]

I enjoyed this but how does he feel about ICF systems?

[@steveklein4367]

BEHOLD this video! BY THE LIGHT! BEHOLD!!!

[@toology55]

Really good video. ICF should really solve all the basement & rim issues in one shot, you should still waterproof with a peel & stick to prevent both termites and moisture (if in termite zone) or spray waterproofing should be fine if not in one.. The aggregate base, insulation & vapor membrane in the slab are spot on, although I would overlap 1" insulation boards then put your vapor membrane overlapped 6"-12" and taped.

[@matthewmillard9775]

What is the rule of thumb when it comes to partially framing your basement? I have split my basement into two parts: one, making a living space that is finished and second a tool space, along with the furnace room that will not be finished? I am planning on using fiberglass insulation between studs. My problem is, that I was told to leave an inch gap between the cinder block wall and the framing, in which I did. My question is will there be an issue with mold having that gap between the wall and the actual framing, since there will be airflow behind the wall. Second question, how much distance the cinder block wall to the stud framing is needed not to need insulation. I have a wall going to be a foot away from the wall due to plumbing. Thank you matthew

[@CanadianNative1]

+Matthew Millard If you want to be really safe go with thermal mineral batt insulation by Roxul. It has the ability to dry without reducing the R value and is a lot better to work with. I'm assuming you've already done the work, but when I finished my basement, I put 2" extruded polystyrene (blue board) glued to the foundation wall with a 2x4" wood stud wall with a pt base plate. Then I put my R-14 thermal mineral batt insulation in the stud space with 1/2" drywall without a vapour barrier. I didn't want to trap water inside my wall. Should mention I am from southern Ontario. At the rim joist, I put the 2" board foamed in place so it was sealed really well. I've read some studies which shows when you have 1.5" or greater with the extruded polystyrene (not expanded) that it acts as a vapour/air barrier. Therefore I taped/foamed up my seals and placed a layer of batt insulation behind it for added R-value. Therefore, at the end of the day my foundation wall had an R-value of 24 with the added continuous insulation thermal break between foundation wall and warm side of wall. I'd prefer to do exterior since it is the best way to go, but I'm dealing with existing conditions.

[@garrettb72]

@@CanadianNative1 thank you

[@MaximilianK1]

so is the vapor barrier sprayed on the outside of the concrete supposed to be only semi-vapor permeable or can it be completely water and vapor proof? What is the explanation of why it can only be that way if that is the case?

[@papoh]

I have been told due to termite risk that using exterior insulation as you suggest is a bad idea - comment?

[@spockmcoyissmart961]

if termites are prone to your area, have your soil treated for termites. There are consumable items placed in small containers in your perimeter ground areas of your foundation to protect your foundation. depending upon termite activity, you don't need to replace the consumables often at all.

[@billylikessoda]

papoh termites do not consume exterior FIBERGLASS insulation as shown in the Video. IT's part of the TUFF-N-DRI and Warm-N-Dri Waterproofing System

[@deerhunter7482]

W.r. Meadows makes melrol and cover it with their backfill material followed by 2 drain tiles,one below the footing and the other on top of the footing.

[@oldarkie3880]

I would be afraid of exterior insulation where you can not see the concrete foundation. Termites build mud tunnels behind the insulation and you could not inspect for that. The consumable termite treatment is really bait stations that must be constantly monitored.

[@tealkerberus748]

I wonder how this compares to leaving a 50mm air gap behind your stud frame and running a dehumidifier for that space? An extra solar panel or two would cover the running cost, and you wouldn't have all that synthetic foam sitting there offgassing and being a fire hazard inside your home. You would have to make sure the insulation couldn't fall out the back of the stud frame and block up the air gap, but that wouldn't be difficult to design in.

[@ydid7552]

All this big $$$ effort - just to save 10$ on my heating bill? Than Id rather pay extra 10$ monthly… I demolished quite few old houses that have non of this vapor crap and they were rock solid!!! And modern build to code are nothing but problems

[@chriskelvin248]

1) To prevent wicking from the soil through the footing, could you not pour the footings on a “runner” of poly sheeting? The excess width could be brought back up and taped into the basement floor vapor barrier. Outside, it would be wrapped up to the bottom foundation wall and fixed somehow. Then sealed over with the outside foundation ration waterproofing. 2) To prevent moisture wicking through the interior face of the foundation wall- Dry Lock?

[@xxwookey]

This guy really knows what he's talking about, but it's a pity he's demonstrating with such feeble levels of insulation both below slab and outside the wall. If you are putting some batts on, it really should normally be a lot more than 30mm/1", especially that image with the battens in so it's 15% thermal bridge. You can't fix it later (or at least it's extremely difficult/expensive). Depends where you are in the world of course. I guess 30mm of XPS may be adequate in some places.

[@brissance31]

So I'm assuming a thin lzyer of closed cell spray foam applied to the interior of the rim joists is preferred to open cell spray foam due to its decreased permeability ?? Please advise as my rim joists are not insulated, and i am planning to insulate them. Home built in 1989 on hill side. Cement block basement foundation. 2/3 of basement block wall is below grade. Home located in Knoxville, Tennessee area. I have no knowledge of exterior barriers or insulation.

[@radioguy1620]

amazing video ...looks like you could just add or hang a common open weave fabric wall drape to decorate cellar with no problems as long as air gets thru. didnt do quite enough explaining on the drainage issue under the foam though if air gets in drainage channels will be wetting surface no ?

[@Baffi_]

Thanks you, guess I’ll be digging around my foundation

[@jr.8509]

Super appreciated the explanation. Definitely just saved me a lot of time and money before I started my project.

[@ml9633]

Hi Pat, I've dug out some area outside. I found the sale fiber insulation as you have on the below ground. We have lots water circulating around our foundation. My question is this: this fiberglass insulation is soak and wet, so cold weather the water must freeze against the wall cause of cold transfer. Wondering why the heck is this used below ground outside? If wet fiberglass insulation does not work in doing it's job, why put it on the outside walls below ground, rigid or not fiber? I'm totally perplexed on this knowledge... please answer

[@k0rc]

This is an interesting video that made me believe the "main culprit" in managing the issues of water, vapor, air, and heat is the use of concrete! With all the "space age technologies" available, what would be a better solution for foundations as opposed to using 100+ year-old technology of concrete blocks and mortar? (cost aside)