Vapor Barriers – When to use them, & when to NOT.. On this special edition of the Build Show Matt takes us on a guided tour through the ins and outs of Vapor Barriers from the studio (Building Science Layer)
https://buildingscience.com/book-categories/builders-guides
http://www.greenbuildingadvisor.com/blogs/dept/musings/do-i-need-vapor-retarder
https://www.energyvanguard.com/blog/54110/You-Don-t-Need-a-Vapor-Barrier-Probably
https://en.wikipedia.org/wiki/Vapor_barrier#/media/File:Vapor_barrier_replace.jpg
https://rbservis.com/interior-wall-vapor-barrier-style.html
https://www.instagram.com/risingerbuild
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http://www.Securockexoair.com/en.html
http://www.Dorken.com
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I want to insulate wood shed with rigid foam panels. Which side of panel faces inside? The shiny foil? I want to put sheetrock too.
you must be keanu reeves cousin or something. your face is the same for almost 10 years wtf. great content by the way 🙂
What would happen if the wall cavity were painted with a sealing paint like paint like kilz before insulation?
what about in exterior walls in bathrooms? lot of moisture in there
Just learned the transfer terminology, "Diffusion'. I learned years ago, from the mold that was always present during the demo, not to use plastic between drywall and insulation.That is the purpose of the paper insulation facing. Now I know the molecular definition.
I am seeking these same guidelines for a "conditioned" pole barn, Indiana, with corrugated steel walls and ceiling. Insulation planned as R19 unfaced walls, R38 blown in ceiling. WALLS – do I forego a "house wrap" behind the steel and only use an INTERIOR 4-mil vapor barrier? Or do BOTH as a wrap will keep the wind from penetrating. Also, for the ceiling, i'll have a STEEL corrugated skin. Should there be a vapor barrier BETWEEN it and the trusses?
plastic is the stupidest thing you can wrap your house in.
I'm calling bullshit, if you build a house to tight, mold around you. Home has to breathe, roof vent, soffits. An everyone has holes in drywall even with a vapor barrier, you have electrical on outside walls. An any house crawlspace people put plastic down versus letting it breath, moisture beyond belief, it traps it
Yea my dad uses water retardant paint in bathroom along with grey drywall forgive my ignorance to prevent moisture . Same for around the sinks any where around house.
Always good information! Thank you for these awesome videos!
Good stuff
Awesome video. Very nice job on it too by the way . So I have two questions number 1: So, right now I don't have any insulation in my attic, and you mentioned a paint that can go on the back of my drywall. Is that something I could use in my attic? I recently vacuumed out all of my my old insulation that's been there for about 40 years, and I was going to reinstall new fiberglass rolls into my attic. I'm In the Zone 3. But we live in an area that gets into the 100s in the summer and in 30s in the winter. I wasn't sure if I should have paper on the back of my fiberglass insulation. Question number 2: so that said, I'm using flat paint on my drywall for my ceiling ( which is a fairly porous paint) and a third of a quart of water in condensation still seems like a lot of moisture that could turn into mold overtime. Why should I not be concerned?
I don't trust the people here to do my attic and do the right thing?
here we vapor barrier the walls but not the ceilings, which is best for here so moisture can leave through the ceiling/roof
Yeah but, what about mildew that's forming in my closets and around my windows?? Older mobile home near Florida state line.
what do you recommend for northern wisconsin.poly on the inside should work if take your time and air seal it with 20-25 r in walls for vinyl siding ?!also keep low humidity in the winter and not very cold interior in the summer.basically use the poly as air barrier as supposed to vapor barrier?or should u use different material for air barrier?
Thank you Matt! I live in Tyler, Texas and I am preparing to remove the styrofoam backed vinyl siding from my small early 80's lake house. I have the original siding and tar paper underneath. So glad I saw this, ordering a book for my area right now.
So I have a split foyer house built in 1974. The house was originally built with a finished basement. Only on two sides I am 4 feet below grade. Other two sides are walkout. It was finished with wood paneling, fiberglass insulation and no vapor barrier. 45 year old house and no mold what so ever. Wood paneling was attached to block with 2×2. Do I use the same framing for drywall or should I build a true stud wall to fit an R13 batt in. I was going to use a vapor barrier but sounds like I should skip that??? I was also going to drylok up to the grade level height. I stay completely dry but figured that would be added assurance? What are your thoughts? Thank you.
My house was built about 1800. The roof burned off in the 1930s and they rebuilt the second and third floors. It's a farmhouse, not a colonial. I'm in Northwestern Connecticut. There is no sheathing on the house, the clapboards are directly nailed to the American chestnut studs, except for where those chestnuts studs were replaced in the 1930s which includes the entire roof. So any notion of a vapor barrier is humorous. When there's a good wind you can feel it in the house.
Never mind how many years I've been doing this, but I'm rebuilding the house from the inside piece by piece. Room by room. I could go on for days about all the decisions I've made and whether they're any good or not. But to the point of this video and why I came to it is I'm at the laundry room now. I'm trying to figure out whether I need a vapor barrier on the inside of the laundry room it's below an insulated space mostly and above an insulated space and next to an insulated space on three sides. The roof, which is well-insulated, but has no exterior vapor barrier, does form one part of the wall/ceiling. Let's call it 30 to 40 square feet. What I'm trying to sort out is do I need a vapor barrier in this laundry room at all? Do I need to think about keeping any extra water vapor in this laundry room and not in the wall? Or is it best to let it breathe? I'm at that point in construction where it's time to make this decision and do it. This is a very shortened version of a very long story if anybody's got this far I wonder if you have any advice. I actually do expect to get conflicting advice and will try to sort it out. Thanks in advance, as we say.
Matt, I’m in zone 3, considering an 1” foam board on top of osb. 2×4 walls with roxil insulation. Should I put the foam board under house wrap or over, or not use foam board at all? Please let me know, thanks.
Here in northeren europe we put insulation on both sides of the vapor barrier. Half X mm inside and X outside. This way the temperature on the inside and the outside is the same.
What about a moisture barrier in the basement?
Matt, would you say that enveloping the exterior of a cor-ten steel container house in redguard and 2 component closed cell spray foam would suffice for all barriers? It would be topped off with some mold and rot resistant siding, like vinyl siding or fiber cement board, light colors on roof and walls to deflect the Florida sun.
I used to work for a contractor back in the early 80s and he always insisted on using vapor barrier on every basement job we finished. Been a contractor for 30 years now and every wall I have found those vapor barrier on when remodeling has mold and rot.
Can you do a video on vapor retarders and the options that come with those?
By code, in Virginia they want plastic one of the wall or all of the walls in the bathroom. In the interior walls. after the rockwool,
So it would be rockwool, plastic, Rockboard, mud, tile
We are really confused by science behind the vapour barrier and building code in Canada. We are forced to install Vapour in the warm zone. However the warm zone in summer time becomes cold zone compare to outside.
We are dealing with mould issue every day and I think that is the cause of condensation due to Vapour barrier of 6mm Poly.
Thank you!
Hey, here's a brain popper. Why not use vapor barrier on both inside and outside of the insulation? That would seem to solve the conundrum, and cover all bases. I'm asking seriously.
Matt, 2 questions for u:
1. U mention that air leaking into the wall cavity is the bigger problem. IMHO, the most likely place that will happen is in the gap between the drywall and the gang box of switches or outlets. How do I best seal that gap?
2. I’m in climate zone 4, Washington DC. I’ve hung faced insulation & if it is raining outside, had the paper facing get wet w/ condensation even before hanging drywall. This has freaked me out & made me think that I do need a plastic vapor barrier. What do u think?
I have some guys building a mother inlaw suite right how. They are using T1-11 reverse board and batten siding. They nailed it to the studs with no wrap. I am worried about it. Inside wall will be insulation only and the interior walls will be tongue and groove wood. I am in Wilson NC climate zone 3. Should they have used Tyvek? If so what will my problems be since they didn't? Thanks!!
Audio too low.
TRUTH — From Alaska to Florida, humidity on the inside of a house will always be higher then the outside and without a plastic sheet next to the drywall, moist air will always be flowing into the wall. Always causing insulation to be severely saturated with moisture. Always causing mildew and dry rot.
what about a vapour barrier for a basement partition? building a bedroom in my basement and i know the walls dont need to be insulated but heat wise i wanted to insulate them so it keeps the room warm.
format was good. precicely what i was searching for. I keep coming back to your channel. you are killing it man!
Loved this! Company I use for insulation was recommending a plastic barrier I am zone 5 thanks for this!
From the Build Bunker. Interesting topic. Another reason for the low air exchange build.
Great Video. I've spoken to numerous people here in Florida. Not one person gave me a decisive answer. (Not even the city inspector) I have block home and wanted to take out the plaster walls and put up sheetrock. Needed to know about vapor barriers. Thanks.
So when building my post frame structures with metal siding and no plywood or osb sheeting… still no vapor barrier? Great video matt
Im ingeneering houses in medium to cold climates and a windsafe and vaporproof home with controlled ventilation requires ridiculously low energy and has top quality air indoors. In medium to colder climates: Moisture is supposed to escape through ventilation, NOT the wall. You put the vapor barrier on the "hot side" (inside) of the wall because vapor will go from warm places to cold places as video says. You also put a windproof net-thing under the fasad on the outside. That way the vapor never gets deposited IN the wall on the way out or blows in to the wall from the outside. Hold in mind that this effect gets reversed when its constantly warmer and more humid outside instead.
I'm in the Houston TX area, zone 2, so I can go ahead an insulate my exterior walls with unfaced rockwool insulation correct?
What about fiberglass bats with paper vapor barrier to the inside of the wall. Are you saying you don't need that kraft vapor barrier, just use unfazed brats. Thanks
Interesting. My kitchen walls are cement bricks (solid) and I’m trying to get the right insulation set up. SW Oregon zone 4. Pretty dry and not much freezing. Gonna go with bats after watching this.