Build Science 101: #9 Vapor and Vapor Control

Comments · 89

• RO

  @robertlebaa5482 · 2 years ago

  I really enjoy this show and am into the building science movement. I am not a home builder or even a remodeler per say. I have a restoration company focused on roofing, siding, and windows/doors. I would love to hear about better ways to rebuild according to building science on these restoration projects. Obviously when doing a full residing job with new windows it’s easier to see how to implement the modern products, but when doing repairs or partial replacements is it even worth “fortifying” that partial area? <br><br>Anyways, please consider the restoration guys and show us how to do our jobs better.

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• NI

  @nikojansen9648 · 2 years ago

  “Vapor can be a liability but it also is an asset” - great great building science quote.

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• DR

  @DrSerendip · 2 years ago

  We have seen houses, built in the 90’s, with the poly vapor “barrier”, that caused significant problems with condensation. We remediate mold and mold issues that cause health issues and building failures. The fiberglass insulation, which is hydrophilic adsorbs the moisture and the insulation is now saturated and enough to wring out the water from the insulation. Thanks for a great series that helps not just in building but in helping to correct issues homeowners run into.

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• SU

  @superfunkysungod · 2 years ago

  This &nbsp;raised more questions than answers for me. &nbsp;The main one being do i put plastic over my insulated interior walls and ceiling, or not?

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• OM

  @omarpopioco9997 · 1 year ago

  Absolutely, incredibly valuable information. (discussion @ <a href="https://www.youtube.com/watch?v=wsBdJiRWFm4&amp;t=1440">24:00</a>) I actually ran into the exact same issue with my home built in 1989. IT took about 30 years for the problem to really tip me over the edge. We have some harsh winter climate in AB, Canada. Due to slowly gradual deteriorating attic insulation, I eventually experienced a more and more perfect condition (in attic and even some walls) to hit Dew Point under the Attic Floor Vapor barrier originally installed. For about a year I kept thinking it was a small roof leak or tiny plumbing leak that just couldn&apos;t be found. The years of collection under the barrier and not having the ability to escape at a manageable rate caused more and more favorable condition for condensing as the air gaps widened along top plates and seams and corner (not even visible the naked eye), and most noticeably around the Flue pipe chase through the first and second floor and then the penetration into the attic. It was so bad to the point where you could feel wet carpet at night as condensation accumulated once the temperature dropped and I forgot to turn up the heat a little more to fight the battle with the dew point. Extremely difficult to pinpoint, as it was more of a highly damp spray type of feel rather than a dripping pool of water.<br><br>I had a few contractors try to help solve this (with no luck) - that didn&apos;t have the grasp of the building science. Not to blame them though, I probably was reaching out to the wrong avenues of contactors to identify the problem (roofer / plumber / hvac). It wasn&apos;t until I dove deeper into the education, and luckily very helpful videos such as this one, that I was able to solve my problem and put a stop to the cause onmy own &nbsp;I carefully ripped out the Vapor barrier underneath the already dying insulation, and did a proper air seal with foam around fixtures pipes and top plates. Careful application of Hi Temp Caulk to Fire stop penetrations for the Flue. And it&apos;s been quite a grateful experience since. It is quite a bit of work however - new attic installation was needed (remove of old at this point was necessary) - insulation around ducts improved a more balanced building envelope, I have not experienced any issues since.<br><br>***But I will admit, if I had kept up with the proper insulation R Value in the attic years ago, I could have avoided the slow accumulation under the vapor barrier over all those nights that it was unrealized. So, friendly reminder to fellow property owners - don&apos;t neglect inspecting things (we can&apos;t remember everything all the time), even if they appear like they are up to par. Open things up - take a close look... buying even a cheaper thermal camera just to get a grasp of where you are losing heat or where air can travel to can save you thousands or even tens of thousands of your hard earned coin. Understand how to apply some of this science and readings behind your tools, It&apos;s a beautiful thing to know whats happening where you can&apos;t see.

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• PA

  @pacodefrancis7235 · 2 years ago

  Great video Matt and Steve. Such an important and misunderstood topic. We all appreciate it!

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• VA

  @valdius85 · 2 years ago

  Thank you for tour hard work.

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• RS

  @rs2024-s4u · 2 years ago

  Vapor management is easier to understand if one knows that managing vapor is more about heat transfer than water all condensing surfaces are being heated by/during the transition of vapor to water and conversely all evaporating surfaces are being cooled by evaporation. Conditioning the air for comfort creates differences in inside versus outside temps. humidity between the inside and outside of a house will naturally attempt to equalize these differences unless steps are taken to replace these heat transfers either by adding heating/cooling and humidity control. Therefore most situations exterior surfaces will attempt to prevent water and water vapor from from moving into the structure and if carefully managed interior surfaces will allow/encourage water/water vapor to migrate inside providing a path for water in all its forms to dry/ equalize the conditioned spaces, this means that the interior wall temps. must be equalized with the interior air temp. as closely as practible to allow drying to occur w/o condensation. Ray Stormont

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• MA

  @macoveialex6823 · 2 years ago

  I love this serios. All the informations needed in one place.

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• RA

  @ralphjean-pierre309 · 2 years ago (edited)

  Community: I&apos;m currently in the process of constructing a new home for my family and myself in Minneapolis, MN. I&apos;m deliberating over whether to incorporate a vapor barrier before moving forward with drywall installation. Our building envelope consists of Zip sheathing 2.0, complemented by R17 EPS exterior insulation and R23 Rockwool insulation within the interior cavity. Additionally, we&apos;re considering integrating a Zehnder ERV system into the design. I&apos;m particularly interested in the importance of including a vapor management, specifically a smart vapor management like INTELLO PLUS.

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• MA

  @markstipulkoski1389 · 2 years ago

  I live in Florida with high humidity. &nbsp; My attic is vented, &nbsp;lots of soffit ventilation and much less ridge ventilation. &nbsp;My attic is extremely humid but my a.c. keeps my house near 50% RH. &nbsp;There is no vapor membrane whatsoever in the ceiling. &nbsp;Just paint, &nbsp;drywall, and blown-in insulation between me and my 140F 90% R attic. &nbsp;So the problem here in the humid South is keeping the humidity out, not trying to remove it as might be the case in Boston. &nbsp;I wish I had a vapor membrane with a low permeability in my ceiling to help keep the attic humidity out of my living space. Opposite of getting interior humidity buildup to the cold dry exterior. &nbsp;The climate zone needs to enter into these discussions.

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• TH

  @theinterpretationstation · 6 months ago

  I know very little about housebuilding but I find these videos fascinating.<br><br>Based on the episode on vapour management, would I be right in saying that, hypothetically, the Holy Grail for a vapour retarder would be a material that lets vapour OUT but lets nothing IN?<br><br>A bit like an LED in an electrical circuit?<br><br>Does such a fabric exist or do you think one could ever be invented?<br><br>Many thanks again to Steve and Matt for sharing all this knowledge 🙏