Building Science Insights: To Vent or Not to Vent

[@Jonb01z28]

I'm not in the industry but do take home energy efficiency pretty serious. Did exactly what Dr lstibuerk explains on my own home in FL, air sealed the ceiling to the best of my ability(probably not perfect but certainly way better than it was which was a leaking mess), put r60 blown in insulation in attic, added ridge vent when my roof was redone and added more soffit vents, even with my HVAC blower in a hot garage(also air sealed it as well as insulated) and ducting in the attic I saw a 20-25% reduction in energy usage and a much more comfortable home in the hot 90-100 degree days here in fl. It blows me away how much we talk about green energy and spending tens of thousand on solar or other super fancy expensive options yet do nothing in most cases for fairly cheap and very good ROI options. Making our homes more efficient should be the first step in helping reduce emissions/ being greener, instead we put up solar everywhere, windmills, buy hybrid/electric cars, set mandates of emissions on everything yet our homes are bleeding fossil fuel every minute of the day 365 days a year, imagine the impact if every home saved 20-25% on energy usage.

[@danhenderson3135]

Joe, that was a great presentation! Thank you so very much for sharing all you hard won knowledge. I totally agree the failure teaches way more than success and that being an engineer with practical field experience the ability to learn from your mistakes is what makes the difference. Also, contrary to some comments, when I set out watching your video I did it with the attitude of "I didn't come a knowin i came a learnin". That bit of wisdom I was given by you guessed it an Old Timer over 20 years ago. Again thanks!

[@NMranchhand]

Fabulous presenter. Thanks to Owens Corning for sponsoring this sort of thing and making it available to the general public.

[@JillofAllTrades2]

Yes, and no. Fantastic information.

[@sergelefebvre6532]

He makes a number of generalized statements that just aren't true: survive an avalanche if you stay calm, 25% leakage of ducting...most of what he says seems to hold however. I would say poor presenter, but good material.

[@chrissnider6013]

Well put, if you've worked in the industry for any practical amount of time, this should make sense, at least in a summed up simplified overview. As he says, we complicate the issue with a lot of "ideas" but the facts and science behind is the way it works, regardless. Thanks for the video, very refreshing to see after 20 years of arguing with "contractors".

[@robertsullivan2396]

As a builder I have said for many years now that INSULATION without VENTILATION will equal CONDENSATION

[@Bobocalc]

He has the tech knowledge... I hope I got the basics right. My attic is drafty, I can hear people on the street, it kinda amplifies the sound, and now I feel good about that...

[@evadevries2952]

High SEER ductless mini splits have worked very well for us.

[@neocollective]

Great talk and presentation ! made me laugh while happily keeping my full attention to the technical content, well done :)

[@Corteese1980]

There is only over-designing or under-designing. A good over-design will cost 10% more than needed. A bad over-design will cost 50% more than needed. Any under-design will cost >300% more then needed.

[@roberterickson77]

That is sound advice and words I live by. I'm a Contractor coming from an Engineering family. I refuse projects where parties want to cut corners.

[@theultimatereductionist7592]

So, then, "what's needed" is cheapest. How would you characterize what's needed?

[@putheflamesou]

A bridge needs to fall once in awhile no? Well maybe not, but have we forgot about tar paper etc and mixed technologies a little too quickly adding costs while defining improvement by $signs rather than common sense which is getting close to illegal anymore. Just saying if my house burns what the insurance glues, I mean builds, I would have to sell to pay the taxes. And I have a old guy built(non hydraulic)(carpenter owned) house I respect dearly. But tell that to those vinyl pushing banks/ins cos. LOL had a young buck contractor stop in. We talked lil about the new smart siding. He said it will prob fall apart, just something new. Job security scare or true? Who knows.

[@putheflamesou]

Hey TUR,,,like to share a sign on a bus bumper I seen on YT video "bus life"......."simplicity is the ultimate sophistication"

[@slaunspach]

knew nothing about roofing or insulation or VENTING , this Dr. Joseph Lstiburek just 'stole' ONE WHOLE HOUR !!!!! almost, of my life, DAMN..... .... .. I really enjoyed this presentation , informative and most entertaining, i may have actually learned something. Thank You.......

[@Impractical_Engineer]

Building science; No one knows what it means but it's provocative, it gets the people going! Great presentation!

[@kokopelli314]

This is one of the best presentations I've ever seen.

[@8172008]

Do not ever stop your comical, mixed with sarcasm, presentation. I love it. I'm sure that it's the only way to get the attention of some people. Keep up the good work. :--))))))))))))

[@daneapeterson]

Had the pleasure of attending your presentation when you came to Vancouver. Brilliant

[@johnsmith-wc8gs]

This presented alot but answered very little. I watched this because I'm a builder and knowledge is key. Perhaps I need to watch again because I'm still unclear on the best roof possible. I hate SIPS. Have never been a fan of spray foam. Simply I don't trust any new technology. Houses I tear into that are built before the 1940s are almost always in great shape. Sure they are under insulated but they never have the commonly found issues talked about here. I've always thought it to be because they can breath. My house was built in 1920. Solid construction with no rot. Ofcourse we can't build today how they built then but sometimes I wish we could. It's not a structural issue because all these home are still standing. It's an energy issue however we spend too much energy building and then fixing lol

[@VertigoGTI]

Loved the seminar! I'm not a builder, but I am a designer and I've had a recent fascination with house design. This video has given me a lot more info than anything else I've seen so far. :)

[@kodguerrero]

The presentation was just as good as the material hahaha. I just wanted to know a bit about something in the attic and I ended watching the whole thing xD

[@TedKidd]

Failure teaches more than success. Go into the field and investigate failure. Min 52 Fantastic!! Ping pong moisture through ridge.

[@markhstevenscms904]

I would agree with moving the Air Handler and ductwork out of the Attic now you just have to convince the builders and Architects who keep designing structures with the mechanics in the attic because they don't want to give up the storage or closet space

[@fessit]

Excellent presentation! I learned a lot!

[@SampleroftheMultiverse]

I was scanning for info on flat roof to put on my first commercial building. Did not think this video was something I wanted to spend time to see. I watched the whole thing with great interest. Thanks for the video!

[@f1lupo]

love Joe's books..straight forward Building Science !

[@jeffwolf8018]

The only ductwork I have in my attic is coming from the fan on my stove and microwave a second and third would be the venting for my two bathrooms going up through the roof. Are those okay to have in the roof if not where do you vent them to? And all my other venting including my washer dryer goes out through my basement including the heating. No air conditioning in my house except for window air conditioning. And I realize that these three events do take some of the heat out of my house but they also take away the smell in the bathroom and the humidity from the bathrooms and the smells from cooking. I also have several 6in charcoal filters at using my grow rooms should I rather have a 6in charcoal filter just of Andre circulate the air inside my house as well? Thanks for any information you can give me.

[@judywarren7154]

The people who understood what that man was saying, already knew everything about it!

[@neenboobean3036]

By people, you mean him. Dr. Lobsterflugen has bats in his attic.

[@joshualruby]

That's not true. I only ever built unvented attics so never knew the science/method behind unvented until this video explained it clearly.

[@fitzfitzgerald6833]

Thank you for sharing this presentation! There was some great theory included that I was previously unaware of and will be using the concepts shown for our attic & roof ventilation. Did I understand how to vent a roof before? -sure, but not as effective as I understand now! Thanks again and God bless!

[@larsonhomeinspection9932]

Love the ridge gap vapor diffusion idea!

[@shawn1557]

That was very informative. I learned a lot.

[@davidvitale8680]

Fantastic presentation!

[@DanJoy07]

Fun! Insightful, to a most high degree. I appreciate the real-world decision making candor. move it out of the lab, to real problem...Now that answer is solid. Thank you.

[@Spencerbuildsit]

Joe, I'd like to hear more on the effects of the urethane glues and resulting perm ratings in plywood and OSB. Much of your discussions are based on vapor permeability and reverse vapor pressure. The more effective the cold attic the less relevant the topic. But in awkward locations like cathedrals it may be an issue. Add a surface coating (Zip) and it's another variable. Your thoughts? thank for the presentations

[@Indy2442]

"In my heart, I know I'm funny"

[@nomore4me286]

Until I watched this presentation I was sincerely within 5 years away from building my "net zero" house. I'm now adding 2 years to that process to watch more videos of this man and others to learn more now to pay less later

[@tomkacandes8286]

We the People United Just buy the books and read them front to back. I have every Building Insights article in a 4” thick binder and have read them all. That will cut a year off your estimated time. Good for you that you want to understand what you’ll be living with.

[@rburns531]

One of the BEST presentations I have ever seen/heard! Thank You very much!

[@neenboobean3036]

You need to watch some TED talks then. This man cannot lecture, teach or convey informaiton effectively.

[@drchamp1902]

Awesome information sir. I’m designing a new house in SW Florida and researching a conditioned roof type assembly. Would an insulated roof deck on the outside of the sheathing with 1x4 nailing furring strips on top and a standing seam metal roof, plus batt insulation or open cell spray foam in the attic work in HVHZ and humid climate?

[@WadePapineauMusic]

Thanks for all the info. Does this same concept apply to standing seam metal roof? (southern Indiana)

[@steverush5392]

...old house Kamloops, would like a metal roof...so if I vent fascia and use wood screw steps over tag roof deck ...will my frozen insulation and ice dams go away?

[@sdowning533]

so many different ideas of what really works. Where can I find the all out truth up to date. Should I close off my crawl space from being vented? should i use rafter vents all the way up to the peak of the ceiling where I have a ridge rent? Have hvac in the addic how to I help that???

[@77gravity]

Rats are smart, I had one as a pet. I'm an Aussie.

[@chuenyeelau]

Fantastic lecture! Thanks & Cheers from Canada

[@pall5114]

Dr Lstiburek liked your lecture. I am not an engineer nor contractor but home owner in suburbs of NYC. Ranch home with 2 story in the back. I currently have gable side vent on each side. Planning replacing the roof for some rotted edges. I do get ice dams on 1-2 corners. Also have recessed lights and bathroom ceiling fan for moisture removal and attic fan in the hallway so the ceiling is full of holes. All the roofers recommend a ridge vent which seems makes sense but only one mentioned installing soffit vents. The others stated I didn't necessary did soffit vents. I can do without soffit vent and install a ridge vent and keep the gable vents open. I understand soffit vents provide intake cool air and exhaust hot air via ridge vent. But with gable vents and ridge vents suffice. I don't think many of the roofer understand much about the engineer or physics behind proper ventilation. For my home what would be the best course a action in replacing the roof. -Also, any thought on underlayment some recommend the time test cheaper cost felt 15lb and other newer synthetic. -Lastly, any recommendations to improve the "airtight holes", can I throw some more insulation over the recession lights Thank you for any advice

[@jadaro2600]

Pall 511, you may want to run your exhaust to the the gable end if it hasn't got a dedicated port on the roof - if it does, consider removing it and venting to the gable ends, this will simply a reroofing. plumbing penetrations can also be removed and their intake with a one way valve ( if code permits ) I see these in commercial buildings, they allow air to go in, but dont let fumes out. look up rockwool can light cover, these can be air sealed. you will want to find where your leaking the warm inside air, and seal the gaps.

[@jadaro2600]

Pall 511, you may want to run your exhaust to the the gable end if it hasn't got a dedicated port on the roof - if it does, consider removing it and venting to the gable ends, this will simply a reroofing. plumbing penetrations can also be removed and their intake with a one way valve ( if code permits ) I see these in commercial buildings, they allow air to go in, but dont let fumes out. look up rockwool can light cover, these can be air sealed. you will want to find where your leaking the warm inside air, and seal the gaps.

[@grizzlygrizzle]

Insulation doesn't come close to stopping air movement. take a chunk of insulation, and place it over your mouth, and see if it stops you from breathing. (Not really, you'll be inhaling fiberglass particles.) I don't think you grasp the concepts here. Try to consider the long term cumulative effects of small amounts of air or water-vapor transfer over long periods of time, with warm and cold cycles occurring every half-day.

[@travelingkaspersworld4096]

Is there another source for this information? Thanks everyone

[@froman1960]

I don't get it. Why do Dome Homes and Arch Homes have no venting and they have no problems. At least, none that I can find. Yet, all the standard American homes seem to have issues galore.

[@chrisboehm7880]

I am a DIY, pretty handy but no professional. have a question regarding ventilation of a slate roof. Roof is original, 80yo, in good shape, roof deck is made of tongue and groove 1x8 boards. I would like to make the attic a living space and need to insulate (location Long Island, New York) the roof to do so. The house has"flush eaves", i.e., no soffit, so the only way I can see to set up ventilation in the usual manner is to rip off gutters, gutter guards, dental trim and fascia and install fascia vents to allow flow up through the baffles to space created by collar beams and out through gable vents. I was told by an old construction guy that I needn't bother with all that because a slate roof over 1/8 are essentially self ventilating so there is no danger of moisture buildup. Is that true? Thanks for any input

[@JillofAllTrades2]

I'll be interested in reading the responses ... I have a slate roof with no ventilation; similar situation to yours.

[@andycastel7089]

53 minutes of a great presentation!!!

[@charliedevine6869]

That was a wonderful presentation. Now I need to see one on crawl spaces.

[@vikfig]

Like your presentation. In home owner want to convert one of my attics to an office I live in Houston TX. What kind of insulation for walls and floors should I put? This is a 1989 home. Thanks

[@benjaminblack5888]

This was an awesome presentation. And right on the mark.

[@benjaminblack5888]

For remodels I would recommend a whole house pressure test to address the air leaks, change to LED lighting, and always vent the deck.

[@59seank]

Thanks for posting this video.

[@TedKidd]

R value of snow based on density, min 13

On SIPs, you goop the splines, not the joints. The vapor barrier (ordinary polyethylene plastic sheeting,) in the ceiling is under the SIP panels, between the panel and the drywall. It's not difficult, it's not complicated, and it doesn't take perfection. At the peak of the roof, the joint is sealed by the ridge beam. I've lived with this in a cool, wet climate for 17 years, with a cathedral ceiling and metal roofing with building paper under it. You can't see where the panel joints are when it snows. There is no attic. Nothing is ventilated. So far, so good.

[@havokterra]

thank you for this presentation

[@timkirkpatrick9155]

Gotta quit the avalanche sim. it does not work the snow density is greater than O2 transfer rate if the snow depth is more than 6in.. this arises due to near freezing liquefaction of the crystals due to motion resulting in refreeze upon sitting without the air spaces the snow originally had.

[@alanhowitzer]

I don't understand the first detail. Where are the holes, in the insulation? Where is the airtight barrier?

[@neenboobean3036]

Isn't it obvious? (throws fist in the air)..... Hint: the holes are in the presentation.

[@AngeloMr]

Dear Mr. Lstiburek. I'm constructing a small roof in Sao Paulo, Brazil. We have no problem at all with snow, but heat is a big challenge. I'm having the opportunity to apply the knowledge that I learned from your videos on KZbin, but still have a small question: what can I do to avoid birds and bugs from invading (and reproducing) at the air layer of my roof (right between the tiles and the insulation)? Thanks!

[@ZephyrWestWind]

Plastic grating/grid easy fix

[@donaldhester9952]

Typically a metal mesh screen and or a bird block designed for the roof profile. www.fasciadivision.co.uk/bird-guards/ www.247wildlife.com/tileroof.htm www.hellotrade.com/eagle-roofing-product/eave-closures.html

[@6789uiop]

In SE Asia termites are an issue. They use metal, not wood (food).

[@JillofAllTrades2]

LOL ... or both.

[@Fmagyar]

"what can I do to avoid birds and bugs from invading (and reproducing) at the air layer of my roof (right between the tiles and the insulation)? Thanks!" Um, you could try putting screens at the places where the birds and bugs might get in. Otherwise, as a Brazilian you should know this: Quem não tem cão caça com gato! Neste caso, literalmente. ;-)

[@douglasthompson2740]

Informative video. I am interested in compared performance with house wrap (Typar, Tyvek, etc.) as compared to old fashioned building paper in 15# and 30#. Also the same question as regards new synthetic roofing underlayments as opposed to a 45# or 30# building paper. I live in a temperate rain forest (Ketchikan, Alaska) where building materials are subject to high stresses. Knowing what works in this environment is important but rarely addressed. Such as when James Hardie sold their planking and it failed totally to the point they revoked their warranty but continue to sell the product. Thanks for your help. Douglas Thompson

[@jadaro2600]

Douglas Thompson where can I read more about this failure? ( hardi board )

[@douglasthompson2740]

James David Robinson Hello, I don't know of any literature published about it. Most journals take advertising from James Hardi so little has been heard in print. My information comes from the real world (come to Ketchikan, Alaska a temperate ocean zone), correspondence addressed to Hardi and ignored, then warranty claims by our local retailer to Hardi that were denied. These are not isolated occurances but uniform failures within a few years. I also installed their product stringently following their guidelines on the web far exceeding the minimums. Just not made to resist any moisture and has no strength. Hardi doesn't make it available but they tell the dealers and bury it in the detailed web info. that in environments with winds over forty need to face nail as well. Over the years they keep adding stipulations to cover the product weakness. It literally disolves with moisture and time. It doesn't hold paint even with a rain shed installation. You won't find any contractors recommending the product here. Doug

[@douglasthompson2740]

PS: According to my retailer Hardi revoked their warranty in the entire state of Alaska. This was twelve or fifteen years ago. Doug

[@matthew8153]

The presenter was very entertaining. But if I understand this correctly the entire video can summed up as: Insulate the roof and make the attic the same space as the house using a double layer of insulation with plastic to separate them. Then put a vented layer on top with the air able to travel to, and escape at, the apex. Someone please correct me if I’m wrong.

[@rmgunter01]

My take was vent the roof. Seal the ceiling.

[@chrimony]

@rmgunter01: My take was that "sealing the ceiling" is impractical. Maybe you can try, but your design shouldn't count on such a seal. And if you've got ducts up there, forget about it.

[@grizzlygrizzle]

There are other options available that render recessed ceiling cans unnecessary, and they're getting stale anyway, suitable for aesthetic drama queens. And in temperate climates, there's no need for ceiling ducts, or any utilities above the ceiling. And if you have clients who insist on one or the other, a little more assertiveness will work on many. Screw the rest. If you can't walk away from a bad client, especially in this market, then there's something wrong with the way you're doing business.

[@nosedoctor]

I think the point he is making is that completely sealing the attic with foam insulation in the rafters creates an airtight "conditioned" space that will effectively be similar to the inside of the house in terms of temp and humidity. This at first may seem counter intuitive to most as they are thinking about the "waste" in terms of heating and cooling attic space, but it isn't in reality because the alternative of trying to seal the attic as separate space from the building interior at the level of the ceiling is practically impossible because of all the penetrations and air leaks. The other point that he is making is that (at least in the south this is true) the HVAC system is usually in the attic and it is incredibly inefficient to try to run this system in the extremes of temp and humidity of an unconditoned attic, especially if you assume the 25% leak rate he mentions relative to the duct work. He is arguing that by using roofing underlayments and foam insulation to isolate and seal the attic (directly below the roof deck), the attic becomes part of the "conditioned" space of the building which all but eliminates the issues with water inside the envelope under the condition that the building structure be protected from moisture coming in through the roof. Given the assumption that penetrations and imperfections will exist in interface between the underside of the roof surface and the underlying decking (in spite of a water and air barrier being in place as an underlayment), you need to allow the structural parts of the roof to dry outward, and this is accomplished by a vapor permeable characteristic in the roof underlayment. The use of the mesh he mentions just allows any vapor to escape from this space between the undersurface of the roof, and the underlayment. He puts it at the ridge because all the vapor eventually migrates there, as evidenced by the earlier mention of finding that all the failures seemed to occur within 8 inches of the ridge.

[@recklessroges]

TL;DW vent 0:53

[@DPaquette]

Excellent presentation. Thanks.

[@kcopp.3178]

Great presentation.... One sure way to not get duct leakage is to use a Hot water heating system. Especially in a cold climate.

[@2awesome292]

What about cooling?

[@kcopp.3178]

How often do you really need cooling? If the home is sealed well and insulated well that will take care of most of your needs. A hydronic system will give you more comfortable home over a hot air system.

[@2awesome292]

During the summer months ofc... We still get temps in the 80s and 90s in the summer time (100+ is rare but it does happen)...

[@kcopp.3178]

I live in New England. I do not have AC at all. I just think it is silly to pick your heating system based on a few days of cooling.

[@2awesome292]

Sure, but mini splits are more efficient for heating especially on days when the ΔT is pretty low.

[@teamfun4u]

Great presentation, I have followed different roof construction for the past 40 years. I am not pleased with the allowable , 20% leakage in ductwork. Not to mention poor quality work left open...a discussion for another day.. that being said conditioned space is an answer. BSI is great

[@grannysweet]

Fabulous! Love this guy. Do you have more of him? Please leave links.

[@332jatc]

So in temperatures of 0 to 30 degrees you should put this kind of Russell from 30 to 60 degrees

[@johnsittel777]

The Summary interim conclusion being air vent above the insulation being the historical satisfactory statement and the maintenance interval known. The compare ending possibility being to the compare in answering the question in possibility had there been the infiltration from the roofing. The condition in air vent underneath occurring with standing. Hot climate one had say insulate the inside. Cold climate one had say insulate the outside. There are portable interior air conditioner, dehumidifier , heater and other such interior space environment stabiliser. The monitoring continue in all grade in building. The study continue. The as is state of the compare is appreciated.

[@kdmq]

Wouldn't you get reverse drying from the outside just by turning the A/C on during a hot humid day?

[@richardwheeler1387]

Geez, a great practical and simultaneously accurate presentation! I enjoyed the tongue in cheek references to the younger folk's age, or " educational malaise, ", aka it is not their fault they have been subjected to so much intellectual absence and manipulative abuse... Not sure your course/lecture would be allowed now, here in the states, as the agenda seems to be to "brainwash" vs. educate. Whatever, you're presentation answered many questions ...e.g. why does my neighbor have such "delicate" shingles??? duh...got it. It could be explained more simple for all of us folks who thought allowing the roof to vent heat was a great idea. ( We don't run our cooling and heating ducts up in the rafters, for goodness sakes, ok). Tight lines, come lobster fishing for a day with me. Sincerely, Captrichie

[@frankenz66]

Heat pump in the attic.. Hmm let's makes some ice cream in the oven.

[@95thousandroses]

I don't understand the illustration at 42:11 . Why isn't there condensation on the underside of the roof sheathing when the warm moist air filters through the fiberglass and hits the cold sheathing? Thanks for any replies.

[@8172008]

My thoughts are that this only works in a climate like Vegas (where this was) that is very dry and tile roofing is used cause it breathes, and 3 tab doesn't, so any moisture evaporated right away. I hope I'm getting this right :--))))))

[@95thousandroses]

I think you nailed it with the dry climate. That was my suspicion. I found an article written by Joe on buildingscience that says just that. Here is a quote from the illustration: "The “flow through” approach is limited to hot dry climates such as Las Vegas and Phoenix." Thanks for helping me figure this one out. Here is a link if youtube will let me to the article which is a synopsis of this vid: buildingscience.com/documents/insights/bsi083-mea-culpa-roofs

[@2awesome292]

because the roof is vapor permeable, there is a gap between the roofing and the sheathing where air can flow

[@JillofAllTrades2]

Thanks for the link!

[@chenelson185]

I have seeing house with 24"wall insolation & 36" insolation on roof for 0 energy consumption no boiler, air tight ,they intake air & exhaust .why the different

[@robertocorradi6318]

Great presentation ....... And really great common sense . Ventilate

[@r.joseph8911]

so, my house was basically designed like shit. Thank goodness it wasn't new construction, otherwise I would've been insanely ripped off. Gambrel (barn) roof, this shape viewable from front and rear of house. No eaves/overhang. The gambrel bottom slopes meet 1- pitch gable roofs which are 90 degrees perpendicular to the main gambrel shape. NO WAY to vent. No soffit at the bottoms. Only great potential for epic ice damming. One of these areas has leaked inside already. I don't know what to do. If closed cell foam didn't require me to mortgage my house, I'd do that. Otherwise, redesign my house. That will take MORE money.

[@jimc4731]

Why not place the ductwork inside the room in the conditioned space?

[@armafide6182]

JIM C several new builders are doing this, using a "plenum" truss

[@grizzlygrizzle]

These still require adult supervision on site.

[@jadaro2600]

A most excellent presentation.

[@hejjrg]

Wonderful, well spirited and a little Catherine Zeta-Jonesy presentation.

[@mr.d8706]

Would anyone care enough to share the slides or pictures from the presentation? Thank you in advance!

[@JillofAllTrades2]

Try this link on buildingscience.com buildingscience.com/documents/digests/bsd-102-understanding-attic-ventilation

[@seanm3226]

Remember to tip your bartenders and waitresses after this presentation.

[@neenboobean3036]

That's "Trip" your bartenders and waitresses.

[@jeremyharris7811]

Spoiler alert; He was hoping for more audience participation

[@deyc3]

All joking aside, this is the straight dope. Thanks for the video.

[@cesarlaso356]

Did I miss the part where he talks about venting houses in hot climates?

[@baucomfamily]

He said, several times, it works best in every climate zone.

[@reginaldwhite7944]

I think the same techniques apply .

[@dogface6040]

Yes you did. It's about 2 minutes into the talk.

[@joshualruby]

This applies for all climates. Around the 1:10 mark in the video.

[@rachelkingsley2469]

Thank you for sharing this with us.

[@danalavery9755]

The problem with insulating the underside of the roof deck with asphalt shingles is the shingles will cook and will not last much longer than 11 years. The shingle manufacturers will not honor the warranty when the roof fails. You need at least 2 1/2" of air space with air that moves to keep the shingles cool enough to last. If someone used this insulating system and installed a sanded peel and stick over the whole roof the shingles would be stuck to the peel and stick so badly from the asphalt bleeding from the shingles and the peel and stick that to replace the roofing they would have to replace all the plywood deck. Not very cost effective.

[@precisioncraftconstruction3959]

Are the slides from this presentation available for download on Owens Corning's website or elsewhere?

[@karldarnit]

You might find them here: buildingscience.com/past-events or at least something similar

[@krisglenn1830]

I wish I would have watched this video before I renovated my house. Every problem he talks about is absolutely true. I live in a high snow load area and never had a problem with ice damming. During a whole home Reno my insulation contractor talked me into spray foaming the roof deck. When it starts to frost at night during the fall you can see the rafters melt clear lines in the frost on the shingles. I’m assuming the ice damming is happening when the snow piles up and holds the heat leakage down on the roof deck.

[@sportscarclinic]

Lots of great information here. I've consulted the Building Science website since around 2003 when it was part of Amherst University's online presence. As a result, I was probably among the first builders in the area to insist on building a vented rain screen on any re-side project, long before it was required by code. Nonetheless, I'm put off by the presenter's arrogant demeanor and sometimes not-so-subtle elitism. It's been said that and "expert" is someone who's wise enough to know what they don't know, which ought to engender a level of humility. The 'expert' in the video obviously hasn't achieved this level of expertise, in my humble opinion.

[@glennandreasson6823]

Excellent presentation

[@332jatc]

I'd like to know what the final and is you pitch the roof of certain way you put the installation of certain way you want to see this thing the best way you can when you spend the money here you're going to get the reward tier if you have more money than you normally them other people you build it a little bit better but you don't get your pay back on that one radiant floors that the better than to hit the floor up when your cooling it you want and basically just going to come down but if you can keep cool without even better

[@billallen1747]

Excellent information. Criticisms of the presenters style aren't helpful and only indicates the critic's lack of understanding.

[@chrisboehm7880]

BTW, this guy is great

[@VincentVonDudler]

Good presentation.

[@davejoseph5615]

So I guess all I can do is try to climb up there and spray-foam around each ceiling vent.

[@alistairmorrish8613]

If you're giving a technical presentation, it's usually best to state your argument without sarcasm...sarcasm just confuses the point you're trying to put across - this is a bad example of giving a lecture.

[@garrettbeezy2680]

PHENOMENAL

[@mattb9664]

It’s scary that the audience are the ones responsible for installing the roofing and siding products for homeowners...but none of them are able to answer any of the basic temperature questions the presenter is asking.

[@JillofAllTrades2]

IMHO: Dr. Lstiburek is presenting new information (as least new perspectives) ... AND ... not everyone is willing to risk being wrong in front of a room full of strangers if they spoke up to answer his--mostly--rhetorical questions. Dr. Lstiburek's presentation style is a bit off-putting when it comes to soliciting answers; he's performing more than presenting, so not really a classroom environment where he would necessarily take the time to wait for students to figure out where he's going, nor is this type of presentation format conducive to interaction. Valuable video regardless; I appreciate the information (tho I did skip the parts where he was listening to himself and FFd to the diagrams where the real lessons are. I also found the information here: buildingscience.com/documents/digests/bsd-102-understanding-attic-ventilation).

[@Spencerbuildsit]

That's why Joe has a job. Understanding the physics and drawing nice pictures for them. It's better if they understand. If they pay attention they will learn. But if not, just follow the directions. The goal is max energy efficiency with causing damage. For you haters of a little humor, lighten up!

[@mikeausra6950]

live and learn ?

[@arshikhur6773]

why don't we have more flat roofs. I see a need for pitch roofs in an area that gets snow. But in the warmer area, why not have flat roofs. I ould like to know how to vent a flat roof. Also, the pitch roofs are quite dangerous and should have a railing around it. I know harness is being used by some, but the majority of workers are day labors who are sent up on the roof, with radio, liquor but no safety equipment. I think it should be mandatory all worker wear harness and full protective clothing. I really want to see railing even if its only installed while working on the pitch roofs.

[@6789uiop]

Harnesses and ropes required in my area. They check. Flat roof with spray foam is done in this area, by some builders. They use flat roofs to maximize building height as dirt is very expensive. Unfortunately they put the furnace and ducting in attics where there's an attic.

[@angelob9465]

Osha requires fall restraint

[@buggsy5]

Only over a certain roof pitch and the eaves being over a certain height above the ground.

[@grizzlygrizzle]

On a 4-pitch? That's ridiculous, except when you're taking toddlers up on the roof. If you're on a 6- or 7-pitch, no problem. I worked for a guy who walked confidently on 10-pitches (plywood, not shingles), but he had the circumspection not to expect that from the rest of us. And consider that there are roof-jacks, adjustable triangles of steel, with one side extended past the point, so you can lift a shingle and nail it to the roof. with a pair of these, you can put down a plank that you can walk on.

[@neenboobean3036]

This man has leaks in his soffets and losses in his ridge vent. Somewhere between my computer and his ego, valuable time and information escaped through the ether. I'd probably gain more "R" value listening to an actual pink panther than trying to decypher his Canadian rafter ramblings.

[@AdamMichelPeterSaab]

Good information. Horable and disorentating presentation. We are aldults, we don't need to be humered this much with bad jokes to be entertained. The subject matter for a builder or enginer is interesting and important enough. More structure to the presentation would be appreciated.

[@neenboobean3036]

Agreed. He is a lousy teacher. He continously makes the audience feel stupid and in the dark. He might be smart, but his greatest skill is probably convincing other people that he is smarter.

[@grizzlygrizzle]

I disagree. Builders are notoriously resistant to change, unless it shows an immediate monetary return.

[@theultimatereductionist7592]

I am sick of house problems. Why can't everybody live in a semi-underground bunker, like the Nazis' had in Berlin? One floor, roll in level from the ground, or ramp from ground into basement. All concrete with a few plexiglas windows for light. Pipes come up from underground.

[@putheflamesou]

wouldn't be profit the $$world of power and greed. The argument, it's communism. I know a communist which says it was a dictator problem. some VWs aren't bad at least wouldn't need 15000 parts stores. Oh yes we wouldn't have all the "stuff" we have. Well the bugs run so must have been engineered, so then must of us are just ginny pigs to possibly lesser engineered hence we have no other purpose but to cause and create junk for...dictators. Why drive? Public transportation was bought and tossed by oil and rubber. Driving cars kills mains and orphans and they knew it. The Venus Project would be a nice lil experiment , say for the youth. Free education, smart intelligent healthy youth with what we have coming...I can't phantom the math. Sit tight...one day the youth(United World Youth Org) will know it is ALL feasible and this will be trivia. It will be...the next line in the sand, this time extreme human advancement. TVP -education, health, Earth, Universe.

[@cindywatkins35]

What can living in an underground bunker do to your brain? You said Nazis. Don't be like them.

[@theultimatereductionist7592]

+Cindy Watkins Ok, ok. I didn't mean to pick on our ol' villains, the Nazis. I was just trying to conjure up an image in people's minds that is common & understood to billions of people so that as many people as possible would understand what I meant.

[@theultimatereductionist7592]

+putheflamesou I NEVER blame ONLY the dictator or some mysterious unnamed "elite". I blame the stupid majority of voters who unnecessarily keep throwing away their power to the least deserving - republicunts & demoturds - each year, rather than voting 3rd party.

[@Ariccio123]

10:37 LOL

[@JillofAllTrades2]

yep!

[@justsaiyansteve]

This is gold. Lol.

[@newguy6935]

Was hoping to learn something here but the continuous bad jokes and the self infatuation of the speaker made it unbearable to listen to. Had to move on. Stick to the science and lose the jokes.

[@juicenot2481]

Hes an engineer he should know, there is no "suck" there is however partial vacuum!