Under Slab Vapor Barrier 101

[@njkay0033]

Very impressed with Stephanie's knowledge but even more with her on cam delivery. Very clear concise and comfortable presentation.

[@DavidNelson42]

Love to see you highlighting a builder in Utah.

[@DesertHomesteader]

Yay...a contributor in Utah! I'll be contacting her when I'm ready to build.

[@wink9970]

Good information and its great to see other climates covered for their methods. Looking forward to more from Stephanie !

[@uninfamous]

Yay, welcome to Utah! Dang, as a Utahan, I wish Stephanie had a KZbin channel. Not willing to use Instagram.

[@SparklySpencer]

Welcome to Utah, great to see another professional join the Network

[@lifeislucci]

I used Stego on my 32’x24’ garage build. Great product!

[@kenfischer3134]

We used the yellow stuff in 20 mil and the red stego tape. Loved the system. But we had a lot of trouble keeping it adhered to our well cured and clean foundation. We ended up going back and heating the tape and burnishing it, and still had a few places turn loose just before the concrete was poured.

[@persistentwind]

I can swear there is a liqui-flash application for that..

[@johnwhite2576]

Try a bead fo sashco lexel - works great for this

[@show1011011]

I would love to see a building science perspective video on the house @MikePatey is building. Its an impressive looking place and I bet there would be a whole lot of geeking out on the technical details. Just the above ground diving/scuba pool is impressive.

[@Rickmakes]

Mike's house is next level.

[@idahocartel]

Def matt should visit @mikepatey build

[@persistentwind]

Agreed Mike's building details are insane - what would be cool to see is Matt spend a few days with Mike and then do a top 10 patey gee Wizz details that Matt thinks are amazing or must do's

[@ganeshlange4354]

I watch your videos a lot and I’m always so interested in the build methods. I’m from Hawaii so needless to say many of the homes are different for us here, it’s great to see the level of importance that you put into airflows, insulation and vapor barriers. Many of the homes here are single wall and post and pier with very small amounts of production homes. We have limited building supplies and a small and expensive labor market

[@sentienthamster]

My builder is fighting me on under-slab barrier. We are doing finished slab on-grade and his objection is that if water gets under the slab, the barrier will hold it against the slab and not let it drain. My point of view is that it will stop it from reaching the slab in the first place.

[@macthemec]

Water will get to that slab regardless, a layer of plastic will minimize it

[@ecospider5]

Well if the vapor barrier is installed incorrectly this can be a big problem. But when done right the amount of vapor that gets to the slab will dry to the inside just fine. So the question is. If they are complaining, can they do it right. Sounds like getting the local inspector involved would be a good idea since they know what is actually needed for your local climate.

[@billmccance7762]

build on top of 6" drain rock so water can migrate laterally and go away but not rise into slab

[@DrMJJr]

I’d use a minimum of compacted 8” GLAVEL, then stone dust and STEGO. Unless the natural water table rises, water VAPOR would take forever to even reach the concrete slab.

[@Krunch2020]

I’d go with 12” of gravel. Or 14”. 24” would be better.

[@carlosbourdet5415]

Something missing from this conversation is the fact that vapor barriers don't need to be perfect in the way air barriers do. The way that Matt and Stephanie talk in this episode gives the impression that, for "vapor diffusion" the vapor barrier needs to be complete or 100%. For vapor performance the barrier/retarder doesn't need to be 100% puncture free to be effective. If its 95% hole free it functions to bar 95% of the vapor. In terms of Radon and soil gas that is a better reason for making the STO 100% puncture free.

[@whatever_12]

Would be great to see some more videos on insulation for hot & humid climate

[@fredsnit5699]

I’m in Utah. We place a vapor barrier under the footers that runs continuous all the way up the exterior concrete basement wall. Because damp rising. And, Because we’re actual pros.

[@marcfruchtman9473]

Really great video. Thanks for the Vapor Barrier 101.

[@XcessCapital]

Thanks Stephanie!

[@rs2024-s4u]

What a well orginazed job site, beautiful forming of basement walls well vibrated, but why no expansion joint on floating slab perimeters? As an owner builder of commercial structures for the last 50 years I always insist on a vapor barrier below to keep moisture in during curing and either wet top daily or cover with visqueen to keep concrete wet for 28 days and eliminate internal stresses that are a major cause of future cracking. Ray Stormont

[@bliss4391]

Very interesting and informative. I’ve learned a lot in such a short time.

[@TRYtoHELPyou]

Outstanding!

[@pcskier3611]

I put Stego Home under my basement floor, and bought the tacky tape (grey, adhesive and release paper on both sides) that they show in this video momentarily. It goes down on the footing edge, then pull the release paper on the top and stick down the vapor barrier. We put the tape down all along the footing, which was cured, clean, dry and dust free. Then when we went around pulling off the release paper to expose the adhesive on the top of the tape...the tape would release from the foundation, and stretch, etc. The paper strip on top was stickier than the bottom of the tape stuck to the concrete. It was a big mess, we switched to the red seam tape and taped the vapor barrier that way. But only had purchased enough for seams, so using it for the edges caused me to run out. My foundation guy had a little left over on his trailer, and a roll of some other type of tape, which we wound up using. To Stego's credit, I emailed them and they immediately refunded the $150 or the three rolls of tape, and a regional guy called me to ask for the code numbers from the rolls, he said they had other reports of this happening and he said it might be in issue with some production runs. So for me, it was a big fail, as I did not get the seal between all the concrete and the vapor barrier that I was going for. Maybe I just had bad batches of tape in my case. But it's crazy that the tape was stuck better to the paper on top, than it would stick to the concrete. Everything I read indicated that once it's on the concrete, good luck getting it off. Mine came right off when pulling on the paper on the top of the tape. Crazy.

[@Timmyotool666]

love the stuff up at 4.20 with the air bubble/seam on the tape...offf

[@bothellkenmore]

She strikes me as super smart and also likes rock n roll. My kind of gal. Looking forward for more content from Stephanie. OK I just watched her bio vid on buildshownetwork and she is super smart.

[@b.anonson8711]

Good commercial for Stego.

[@mr.g1683]

Good insight and content in this video thank you both kindly. Good job out of you.

[@PanoMono]

It has been a long time since I have built a home, but I have built over 100. It was common when the concrete is being poured to get bubbles in the vapor barrier and the guys would intentionally puncture the barrier at the bubble to release the air.

[@am17frans]

Welcome Stephanie.

[@AndrewEClark-mz6ch]

I sure hoped you stopped by Temple Square to take in the EPIC seismic upgrades to the temple. They are employing all the latest and greatest building science and techniques on their several projects.

[@onedelish]

Nice mat

[@K1LLA_KING_KONG]

another question is: do you have a vapor barrier under the footings as well? If not what are you doing to prevent capillary action?

[@AOED_Official]

Same question … Matt seems to say it should be continuous but it doesn’t look continuous at those interior walls

[@CarlGolden]

Help me understand. If concrete wicks moisture then why are they not continuing the vapor block up the walls? I get there is protection on the outside but the footers don't seam to be protected.

[@13Stevenpoll13]

outside of the foundation wall will have a waterproofing sprayed or rolled on. Utah is a dry climate, therefore the moisture of concern is coming from outside/below to inside. I believe it is also important not to trap the moisture in the concrete, I am not sure if the exterior waterproofing is vapor open, but for sure Stego is not. So putting plastic up the walls would trap moisture in the foundation wall and when it freezes, will expand and cause cracking/structural issue. Also, depending on how they finish the basement, they may put a vapor barrier over the framing, between the wood and drywall, thus protecting moisture from driving into the foundation from the slightly more humid interior. My 2 cents, happy to be corrected if my thought process is flawed.

[@Chiefmonohan]

I agree with you.I wrapped my footers and walls too. None of my concrete touches any dirt!

[@Nobudee]

There is fast-foot from FabForm. It's a woven-plastic sleeve that you directly pour the concrete into (a long bag that is strong enough to be the form too). Later on you can tape and seal to the edge of the bag so you have continuous vapour barrier from inside to outside. That said, the surface area of the footer compared to the rest of the structure is quite small, so migration of gase/moisture isn't a lot 99% of the time. It'll dry to somewhere, eventually. Additionally, while not its purpose, the active radon system will be sucking air down under the slab, so may be drying the footer as a side effect of its actual job.

[@rs2024-s4u]

The grade beams do not need water protection as they are buried below any occupied areas and w/o air/Oxygen the steel rebars cannot rust and cause spalling even if the grade beam develops a crack. Ray Stormont

[@Treehandler]

Outside of foundation will be coated and with proper drainage, any residual moisture will be taken care of my a dehumidifier or air exchange.

[@yatessnyder1490]

Can you put this on top of the concrete when finishing an existing basement of a 1960’s home?

[@Werdna12345]

Let’s get going!

[@Coleen-Love]

Really good video Stephanie and Matt -- QUESTION -- We are a bit confused on the insulation/concrete/stego order. For the basement slab, does the poli sheets of insulation go under the slab or above the slab? Does Stego go on top of the insulation and under the concrete? What is the specific order that these materials should be laid on a new build in the North East / colder climate? I thought that Steve Basic put insulation under the concrete but I can't find that video.

[@inventor1214]

Welcome to the Great State of Utah!

[@Patrick_Cashman]

I have yet to see a video using the Stego products where the vapor barrier in the floor is tied to vapor barrier in the walls. According to Joe Lstiburek, you should be able to follow the barrier using a pencil on a cross-section view without ever lifting the pencil off the paper. I don't see how that would work in this case.

[@bryanhickman7663]

Would like yo have seen an example of what was actually done at the walls to interface with the floor. Or did I miss something?

[@donbowman2312]

I’am building a 30’ dia. 6” thk. Concrete slab for a Stargazer dome house. Do I need a vapor barrier as technically I will be putting a floor in it ?

[@user-tv5dt3nm9y]

Why not use a wall flashing from Oatey over floor penetrations, taping them in place?

[@ronmelcher4723]

Joseph Lstiburek says you can walk all over the moisture barrier with golf shoes and it would still perform well

[@samyoungblood3740]

I’d love to see an engineer’s idea using todays technology and build science-how they would replicate Derinkuyu in Turkey. An underground city laugh enough to hole the entire city’s population, animals, food storage, air shafts.. etc.. fascinating concept considering the world today. Replicate the ancient underground cities in various places around the US

[@Faithful_Tribe]

Is this Mike Patey’s house? 😅 Matt you should go do a tour!

[@regulatorct]

100% would love to see a @mikepatey build video

[@metalbill]

I’m in Nevada. I want to meet Stephanie

[@ecospider5]

My basement has a proper vapor barrier. I had a toilet and sump installed. The had to remove a 5’x3’ area of concrete. When they repoured the slab they did not do the vapor barrier correctly. So the whole slab is 45% moisture except that area. Which is 70% sometimes. I had to choose. Try and seal it or try and let it dry. I figured sealing it would push that moisture to the rest of the slab. So I have removed the flooring and just have the concrete open to the air. It stays at 55% now. I’m lucky it’s in a closet so the flooring doesn’t matter much. .

[@philipoakley5498]

From UK: Those 'mills' can be confusing ;-) I'm assuming the terminology is "thousands of an inch" in US, while I'm far more used to millimeters being abbreviated to 'mills' so easy to confuse. All good stuff.

[@inventor1214]

As an American I was confused as well XDXD usually thousandths of an inch are called "Thou's" but looking it up yes, mils is equivalent to a thou

[@David_Mash]

Why is the vapor barrier not on the outside of the foundation?

[@patrickdougherty2777]

To be clear, I also was wondering why it was not under the foundation

[@billmccance7762]

it can be if you use Fastfoot or the stego under footings@@patrickdougherty2777

[@steveb365]

Geoliners...the whole industry needs to get onboard with encapsulating slabs and basements entirely. So many billions in damages would be saved over time.

[@raybudau9920]

Why no reward or mesh in floor? Or you using fiber

[@TheJagjr4450]

I used 20 mil pond liner as my vapor barrier in my house and my shop.

[@poohbear4130]

Important details that get covered up and never seen again, like they say the devils in the details!

[@jackjohnson9449]

Why are they pouring a basement slab with no rebar in it?

[@2kings3queens]

"Concrete is porous" so how are the footings addressed?

[@tysleight]

Currently SLC is 39% humidity has not rained anything more than a dusting since August 3 Is how. Also the actual amount that is touching the ground is minimal there is 8-16 inches of concrete keeping the wall out of the mud. Any water that does make it up is dissipated easy

[@K1LLA_KING_KONG]

When you say 6 and 10 mil. You are not talking about mm (millimeter) obviously, so what units are you talking about?

[@antoniocollazo490]

WY there's no rebar in the basement floor

[@capedcrusaderforbuilders9671]

You ought to go to Chicagoland and the adjacent counties up in northern IL and ask why they won't allow PEX plumbing (all must be copper), won't allow romex-type wiring (everything must be in conduit), won't permit wood or engineered wood floor beams for main floors over basements (all must be steel), and hardly anyone does Zipwall, going instead with cheap housewrap and OSB, and most all exterior framing is on 16" centers. Ain't no science going on here. Just deference to the unions. The region experiences hard subzero winters, but there is no focus on energy. And rainscreen walls? Forgettaboutit.

[@samyoungblood3740]

Is this the best building style in the event of a nationwide blackout if power grid went down, or a nuclear attack? Would sealing a home tight be the way to go if you have no power to run any a/c, Dehumidifier, exhaust fans etc

[@moocowzrock]

Worst case scenario you can do what literally every other house can do for ventilation and open windows. Otherwise, air-tightness and insulation definitely protect your interior space from the wider temperature ranges outside that you don't want to experience. You add in solar and batteries to the mix and you're even better off.

[@ToIsleOfView]

Where is the insulation?

[@TheHalusis]

Where does the gas go?

[@Spaced_Out_Bill]

Don't know much about vapor barrier but seeing all that uncapped rebar and no safety glasses makes my eyes hurt.

[@stevenzawalick49]

What would the actual additional cost be if you just used good thick plastic? 99% of the cost in this is the labor. Why would you ever lobby to make the plastic thinner or use thinner plastic?

[@13Stevenpoll13]

11 Cents per square foot additional per stego's website. granted you could use the husky brand and get the 15mil for only 3cents/sqft more than the stego 10mil. All that to say, you are probably right, but for a contractor, a penny saved is a penny earned unless they are doing cost plus...

[@benzun9600]

wow no video of the floor great job lol

[@MerkDolf]

😄 👍👌.!.

[@ecospider5]

It is really hard to compete with second generation knowledge.

[@tifacola]

I feel sorry for the people that will buy a house in what sounds like a spring.

[@tomadey3904]

10mm? That's not 10mm. What do you guys mean by "10 mil" over there?

[@corba197]

A mil is a thousandth of an inch.

[@tomadey3904]

Thankyou. So much room for confusion!

[@peterxyz3541]

Amendment to go from 10 mil to 6 mil…? I need more info. Is 10 mill an overkill? Is 6 mill cheaper crap that boost profit for builder? Where’s the truth and evidence?

[@PhotonHerald]

Oh lord! The doofy "ON THE BUILD SHOW!" thing is spreading! RUN AWAAAAAAY!

[@ProTexTV]

In Texas, they can't build a house that doesn't fall apart in 10 years.

[@Travis_LTE]

How many hits does it take Matt to drive a 16 penny nail... he's never done it