Is a Zero Perm House Wrap Stupid?
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- čas přidán 21. 08. 2024
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How permeable should a house wrap be? This question comes up all the time among builders and architects - In todays video sponsored by Polywall we’’ll be discussing the A+ wall system, and whether a zero perm house-wrap can work!
Big thanks to Kristof Irwin of positiveenergy...
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We need a norther version of this video!!!!!
Good call! Yes. I’ll add that to my list
A northern version would be greatly appreciated
You mean the testing was only done in a sunny, Southern climate? Isn't WUFI good anywhere, at least if you only need the house to last for 10 years? I'm sure they've got the modeling of complex three-dimensional airflow networks in walls down cold. Sort of like weather forecasting models do.
In cold climates, the vapor barrier goes on the inside, so you want a permeable wrb to not trap your moisture within your walls. However, some northern climates have humid summers, so you need to check your specific climate zone and local building codes.
You want a tyvec type outer coating here in the north. All it takes is a pinhole in the inner plastic to get a lot of water in the wall. Also for attics you want to mix cellulose and fiberglass since fiberglass looses it's R value when you are at -40.
I've learned so much from Matt. Joe Lstiburek and Martin Holladay's articles have also been hugely helpful. I design stock house plans which can be built in any climate zone. I've settled into a flash&batt system in 2x6 24" o.c. framed walls. It's a compromise on insulation because I still have thermal bridges at studs. But with insulated headers, 2-stud corners ... I've reduced thermal bridging by at least 1/3. Having closed cell foam on the inside face of the sheathing puts the vapor barrier in the center of the wall, both physically and thermally, so that it works in both directions, with the wall able to dry out in both directions. I avoid the complications of waterproofing openings that arise with exterior insulation. But I do have to detail out the air barrier carefully at the joints between walls and floors or roofs.
One way or another there is always a trade-off. Which ones we choose depends on our circumstances.
However, a growing number of states are starting to require continuous exterior insulation for all new buildings. Washington, for example.
@@zilfondel Yes, this is one of the dilemmas of designing stock plans. Every jurisdiction has its own quirks. My approach has been to try to detail in a way that is easy to adjust. So for flash&batt I specify 1" of closed-cell spray foam for zones 1-5, 2" for zones 6 and 7, and 3" for zone 8, adjusting the batt portion. This keeps the right percentage of foam to batt and it all fits within the same wall thickness. Also, I exceed the minimum total R value by 1.5 to 8.75.
I've only been doing the stock plans for a few months. So far I haven't had any problems. Hopefully that will last. By overshooting my R values I can show that the "whole wall" values, accounting for the reduced thermal bridging from my framing details makes my wall sections comparable to having continuous exterior insulation.
I've built a few homes housing art collections worth hundreds of millions of dollars and used two layers of 15# felt. This was directed by the top people in the industry who were approved by the insurance companies. Quality control and constant inspection of the work is very important in making this work and the assemblies were different in the sense that I've never sheathed a house in OSB, but only plywood.
I did build in Zone 4. A lot of things might work fantastically in Austin that would be a disaster in Seattle.
All that said, I always used impermeable membranes under the interior drywall or plaster in wet rooms like saunas, bathrooms and laundry rooms. That requires a layer of plywood on the interior face of the wall studs.
I should point out, using two layers of standard 15# felt is actually much more expensive that using an impermeable barrier system. The labor eats up any cost difference in materials. The base layer needs to be wetted and allowed to dry (wrinkling) and the top layer painstakingly applied over it. The details on the perimeters can get really complicated.
Somehow missed this video, glad to have found it.
Searched though the comments and not seeing it mentioned, so will. To me, using a zero permeable WRB is about control, just like an air barrier. By not letting moisture in, there is less dehumidification needed, as the system only has to address the inside load. Similar to an air tight house, the HVAC only has to handle the inside load, rather than also having to condition the infiltration.
I think the major concern with zero perm house wraps is if there is any infiltration of water then it won't be able to dry to the outside. That's why we are meticulous with the tape and the liquid Flash not just slapping some Tyvek up there and calling it good. Certainly zero perm barrier makes sense in the hot humid South but less so in the mixed heating climates.
They're WUFI analysis was only for Humid South, zone 123, not where I live 4-5
This was a fantastic video!! Please have Kristof Irwin come back more often. You guys really covered this information very well together. Great work!
I'm interested to learn how this product performs in colder climates, since the perfect wall always shows insulation outside the air control. It makes a lot of sense for warm climates though to seal the warm side.
In general, it will perform poorly in cold climates, but I'm speaking from Canada. You're generally required to have a
Ed Unless you're in the south where the humidity is on the outside
It doesn't because what you use is dependant on where you want that saturated warm air to concentrate and release the moisture in it.
In cold climates it's inside and in warm climates it's the outside.
Vaisala for example has a free tool for counting different variables of moisture in air flow www.vaisala.com/en/lp/humidity-calculator
@@Ed-ti1ss right, but the problem is that we put people inside buildings, and people produce lots of moisture: breathing, bathing, laundry and cooking in the kitchen produce tons of water vapor that is going to condense and saturate the interior unless you get rid of it.
You want a tyvec type outer coating here in the north. All it takes is a pinhole in the inner plastic to get a lot of water in the wall. Also for attics you want to mix cellulose and fiberglass since fiberglass looses it's R value when you are at -40.
In Florida, the WRB is required by code to be a minimum perm rating of 5x the exterior sheathing. Based on standard OSB, that means the WRB has to be at least 5 perms.
Would be interesting to see for these materials : Cinder-Block, OSB, Zip sheeting, Steel, AAC which are the most common building materials for walls.
As a very practical and experienced but fairly science oriented builder, I note a couple of things.
1) Water passed via permeability is very low; by "holes" is very high. For these houses/ climates, my take is that the Alumaflash Plus is very much the superior approach, but not because of zero perms. Rather, because of the SELF-ADHERING AND SELF-SEALING properties. Any wrap that does not do both is vulnerable to holes and tears, that become LEAKS, of air and water. There are all kinds of assaults on the wrap in the continuing processes of completing the exterior envelope (fancy way of saying it gets impacted and fasteners punched through it, extensively). That potential for leaks is in my mind the death nell for traditional wraps. The lab tests are irrelevant; real-world performance is everything. As built and demonstrated here, this control layer must have zero vulnerabilities (and the perms are along for the ride). I think it is also crucial to note the use of the caulking/ liquid applied (blue) at all the intersections. The down side of sheet goods is the inability to cover three-way (three plane) intersections monolithically and absolutely. There is always the point of intersection that is "open" on every layer, and must rely on a sealant being applied. I doubt anyone will waste their time discussing the perm rating of the blue liquid applied. That is simply not the critical attribute for this material at these points of use.
2) If the demonstration and analysis is for cavity-only insulation, then they have lost me already. I can't warm to (HA!!) anything short of continuous exterior insulation. One can argue the fine points of material choice, etc, etc, but the fact remains that continuous exterior has a far better overall performance for the building envelope. I have done this for compact roof assemblies (including with conditioned attics) and for exterior foam insulation for conditioned basements, for over 40 years now, and first did continuous wall insulation over complete liquid applied (vapor permeable) a decade ago. No reason to discontinue that practice.
Alumaflash would be good behind a reservoir cladding like brick where you want to prevent internal moisture drive. Lstiburek recommends taped XPS with air gap and drainage plane (for brick)
Look closely: this actually shows that using the aluminum wrap, it's dried out in the summer (down south) due to the use of Air Conditioning dehumidifying it. The data is clearly showing the opposite of what Matt is describing at czcams.com/video/xPXcnioVBFw/video.html He's pointing at the graph moisture peaks, but those are in the winter, where moisture from inside the house is migrating to the outside. (Look at the actual dates on the x axis of the graph) The way I look at it is: Where is the water vapor barrier? then figure is there any case where the moisture on either side of the barrier hits the dew point. This is key. In the North, if you put a water vapor barrier on the outside of a house which is heated inside in the winter, there is so much water that the insulation becomes waterlogged, soaked in water, to the point that insulation becomes worthless and mold goes crazy. On a side note, if you use closed cell foam insulation, you can probably get away with just about anything, but with fiberglass or wool insulation, moisture will readily go through it.
Good stuff Matt, give us more Kristoff!
That guy seems seriously smart.
I love how he talks about Tyvek without saying the word
Matt, all good and well, but we know what you choose on your personal build...and it wasn't Polywall. Installing self-adhered wrbs are a pita. Lots of labor and they are fiddly. Simply easier to use Zip
I'd love to see more of Kristoff on the channel. Maybe a bit geekier content, but he deserves a bigger audience. I listen to his podcast.
Good question. For me it boils down to exposure and budget. For a high exposure house I go AlumaFlash all day. Overhangs and a budget, Zip.
Agree. More Kristoff please
henry blueskin vp100. better than zip all day long. and no particle board involved
@@welewisiii OSB isn't particle board, and the OSB used in Zip, Advantech, is far better than ordinary OSB.
Problem with Zip is requirement of good seals at taped joints. Given dust and other realities of the jobsite there is a high risk of poor adhesion. I see people going away from Zip back to Tyvek. Basically the issues is that your sheathing joint aligns with tape joint. Tape failure leads to water infiltration at sheathing joint. Tyvek joints do not align with sheathing joints, so failure there does not automatically become water infiltration.
I understand what your study was about. Basically it will be a very tight house. My question is, what do you do for good indoor air quality? When you get to much carbon dioxide build up in a building the occupants are affected. You see that in large commercial buildings in conference rooms with inadequate ventilation. You need some way of exchanging the air x number of times per hour. So does your air handler (furnace) have an outside air intake that mixes return air with outside air? I love your show!
One smart dude Kristoff. Will follow and subscribe as well
Matt, I'm out of SA and I built my own house. I love watching your channel and the progress and methods you're using in your own personal house. Thanks for sharing all of these more advanced tech approaches to building and remodeling.
It needs to dry in one direction. The vapour barrier (poly) on the inside would (required in Canada by code) would be the Achilles heel.
Poly on the inside makes sense in the Canadian climate.
You CANNOT use a zero perm exterior and then use poly sheet (or equivalent) on the interior of the cavities. That is a disaster, and only a fool would do such. We sit with the plans examiner and get a written sign-off on NO interior vapor retarder on any exterior insulation/ air seal job. Guarantees we will not be harassed for doing it correctly, before we start construction. We have negotiating room then, none at all when being inspected after that part of the work is completed. Poly sheet is useful only for keeping moisture trapped in the cavity, and does relatively little to keep moistures out in the first place.
Well the Canadian codes calls for poly so the insulation, WRB, has to be vapour permeable.
Make it an option, but assemblies need to dry in one direction or the other.
So I get that if you keep the house sealed then you do not need to worry that much about the cold line in a house, because there is never that much water in the house, but how does this work, if you want to open the doors and winds in the spring and fall when it is nice out, would that humidity cause issues and ones you let it in never truly come out?
So how does Aluma Flash Poly-Wall compare with the Zip Hueber Wood? I am planning to start building soon and in climate zone 4 my plan is to use Zip R Hueber Wood for exterior 2x6 walls, CoraVent rain shield, and James Hardie lap siding, and for the foundation walls waterproof membrane, 2-inch non-permeable rigid sheet insulation, and lastly covered by water drain sheet with geotex cloth that runs down to the footing drain.
"Can be left exposed for 24 months" I bet the neighbors love that factor! ;)
Can you do a similar video on northern climates? From my limited understanding, an exterior vapor barrier can be a problem because the warm humid air is on the interior of the house. So if it migrates to the exterior, it will condense on the inside surface and cause a failure.
So if a Interior Barrier is properly installed (house in Northern Zones) and a Dehumidifier is set to control the Humidity to say 20% maybe less, no problem. But damn is it possible to seal every hole unless you use AeroBarrier?
And we KNOW the production builders are not going to use these dang expensive procedures/products!
You want a tyvec type outer coating here in the north. All it takes is a pinhole in the inner plastic to get a lot of water in the wall. Also for attics you want to mix cellulose and fiberglass since fiberglass looses it's R value when you are at -40.
If the two perform alike with water, I'd choose the aluminum wrap, since it will let less heat pass (reflects more) when the cladding gets hot. Don't know about cost... they only sell Tyvek around here, but most people build with mortar and bricks, or even concrete. Wooden houses are rare around here.
So in the south you don't put a vapour barrier on the inside face of wall? The cardinal rule for me is vapour barrier to warm side and let everthing outboard of that breathe - you have to understand where your dew point is in the assembly and ensure it can deal with the condensation. You can tell from my spelling we are talking about Canada and cold climates. The important distinction here is, regardless of location, a do not lock your wall assembly inside non breathing materials. We have had lots of issues with acrylic stucco on conventional northern climate wall assemblies.
Maybe...
So I have done a lot of resi work in Montana. I am now doing commercial and civil in CA. Building science has really been one of the added value items I try to bring to differentiate.
It really depends on your environment. If you have a consistent temp (ie, FL where it is always hot and humid), or northern Alaska (almost always below 80) you have one direction with moisture drive.
I personally prefer to control moisture and vapor, but there are some regions where it is risky. Exterior insulation opened the door to more control as it is always going to offer a safer spot to drive moisture with its inherent resistance.
These open ended comments & CZcams Title Posts...... LoL
@@theMekanik The challenge is the builder and owner have to make the decision. $$$ is what it comes down to. I have done a fully vapor impermeable installation in Montana, where the temperature swings from -20 to 100. However, it was a conditioned home in the summer, heated in the winter. Moisture drive is *almost* without exception out of the wall system, so there is a vapor barrier on the inside driving it out. In that situation it works. If it were unconditioned it wouldnt.
No solution is perfect, there are tradeoffs, and they almost always boil down to budget, performance, and life expectancy. Many people build for a 20 year life. that is it, because they know they will move. My clients want multi generational homes. My preference to build anyways. It may cost 50-100% more to build, but it lasts 100 years.
Love your channel, but I wish you would provide more education for climate zones 4-6. I know you live in Austin but would be helpful for everyone in 4-6 to know if what you are doing works just in zone 2 or 3 or applies the same in the other climate zones.
Matt is a big believer in the Perfect Wall, so most of his stuff applies to zones 4-7 as well. The biggest difference I can see is foundations--Matt can afford to build un- or minimally-insulated slabs, but further north you'd have to either insulate the slab to keep the earth beneath it above freezing all year or build stem walls or basements.
The physics is quite simple if you want a proper house you need a quality vapor barrier on the hot side of the wall.
In hot climate (24/7) you need a barrier on the outside of the wall/roof in colder climate where you have a warmer area inside you need a barrier on the inside part of the wall/roof. This rulle is for water vapor (mold) you still need a rain protection/curtian on the otside of the wall even if you have a vapor barier inside like in colder climate this aditional barrier must be vapor permeable like a goretex for people .
Great video - late comment. What you didn't discuss was the area under each graph which would give the result of the total amount of moisture retained in each assembly over the full test cycle. It looks like the closed in system has flatter graph peaks and the open system has narrow tall peaks. This would indicate that the closed cell framing is exposed to more moisture.
Matt, please do a video of building zone 4. Love the videos, thank you for taking the time to educate us on building science.
If you have refrigerated air conditioning during the warm/hot moist/wet season and moisture can permeate to the interior, the walls will dry and the AC will remove any moisture that gets in the wall and permeates to the interior. During the cool/cold season and the heater is running, any moisture permeating to the interior with help keep the inside air from being too dry.
There zero perm wraps are only zero till the siding is nailed on. So I don’t really understand it because with all those thousands or nail penetrations, if water gets in, it seams trapped. If it’s not perfect what happens? I suspect many reported failures are from production builders that can’t charge enough for Matts level of detail.
The assembly dries , that's what is important. But remember a small pinhole will let warm humid air out .. as he says air transports humidity out in winter
This is the guy that you did a vid on radiant cooling with! We never heard any more on that, I was hoping this was going to be very good/popular way of cooling homes in Texas!
Humidity control is vital on that scenario, otherwise major condensation and rot problems. See Singapore Airport for a (so far ) successful application thereof.
I am also a PE and we must remember 2 things. Matt builds from plans developed by architects and engineers and his only responsibility is to install an item per the plans correctly. Secondly his videos have become commercials for the most part. Don't get me wrong, I do like watching, but I can make my own decisions about the product. In this video, if the wall was sealed so well, why was there an increase of building material during rain storms. That says the polywall stuff is not perm 0. My other take on this was that it is not worth the cost to do the polywall. Always give me a wall that can dry in both directions.
Man, a Build hat would be awesome! Great video. If you can build it right, it will work. It’s all about the details.
Will you ever do a video on invading insects, bugs, rodents, ???? Sure would like your preventive thoughts on this.... Thank you in Advance....
He has touched on termites in some videos over the last year. But yes, it would be great to do a few videos specifically on that, especially as we're doing more and more rain screen sidings.
What exactly are you asking?
He has one where he puts out a spray and boric acid powder. Probably easy to find with a quick search.
Hard for a rodent to bite through aluminum.
Incredibly valuable information. Thanks, Matt and Kristof.
Hi Matt, love your videos. I built a passive house in zone 6a, 4” foam exterior
Talk talk talk. Nice to simplify and get to the point!
Appreciate the climate zone discussion but in climate zone 1A this assembly is almost never used for residential projects... we do not build houses in Miami using wood framing... everything is block construction as its typically a limitation of the building code here. would love to gather more information about these types of systems with CMU style construction.
Please stop interrupting and let him share his knowledge, Matt! He was explaining the functioning of the different materials, he got interrupted and afterwards never finished his train of thought. Such a loss 😔
1st 30seconds: OK. first off, I think this is a gonna be a very interesting video...
Q1: Can this be used on concrete walls too?
Q2: How about finishing?
Basic Mech Eng Thermo. Great idea!
Kristof Irwin and Matt Damon, profile doubles. Great video. Thanks
Have you ever done a video on foundations or are the videos mostly about insulation? I figure foundations and framing are the major factor in longevity then insulation and siding. All in all I enjoy your channel!👍 thank you.
WRB is permeable to allow for failures in construction due to cheap unqualified labor and lack of oversight on most residential projects. Another reason is the traditional aesthetic in the US that demands many funky condition that are hard to seal effectively. If you have excellent quality control and right design you should be able to use impermeable in all zones.
With regard to vapor barrier on the inside I am skeptical of the benefit. With constant interior climate, amount of water is not significant relative to what's coming in from the outside. (another reason why keeping vapor barrier out on the outermost layer of the wall makes most sense)
Therefore, using vapor barrier on the inside, as it is hard to install with multiple penetrations and discontinuities at floor and ceiling, I would not recommend it. Use Rockwool insulation and it should be fine.
nerding out with Kristof, excellent stuff
Zero Perm House will (is likely to) work if you implement it perfectly and it in fact becomes zero perm, but if the construction company is sloppy or makes any honest mistake then you have more issues when you get water into system that is not supposed to get any. So if you go this route, you better pick best in the business contractors.
To keep dewpoint in the foam, used WiFi to simulate. I planned on wall drying to inside so used borosilicate paint to allow permeability of drywall. Passive house training said primer and two coats of paint is nearly zero perm. Have you considered this for your projects with the aluminum looking barrier?
Most latex paints aren't that bad (1-10 perms) unless you're dealing with something like a "bathroom" marketed paint. Vapour retarders are also only proportionally effective, so you likely have diffusion through the rest of the assembly. And air movement through other penetrations.
It's good advice for a passive house, where the margin is more important, but probably not an issue for the majority of builds.
I do wish building inspectors in Canada would accept impermeable paints in place of poly though ;)
WRB: Water (or weather?)-resistive barrier
Weather is the term... But for all intents and purposes it means water.
When was this filmed? Super weird seeing two dudes standing close and swapping spittle and fomites.
Normal is the new normal
It’s not really that weird.....
Filmed in January.
Wait, did I miss something? What about all the nail penetrations from holding on the final sheathing? Like vinyl siding.
That’s what is good about spray on or peel and stick with a butyl lot similar layer. They are self sealing at penetrations. I won’t use regular house wrap.
This new buildings are an assembly of (to be) hazardous waste, basically a nightmare to come.
Enjoy the content.....this is a question that's been debated forever. I agree with Matt's method.
I live in Ct. And I see Tyvec and seeing more & more Zip. Haven't seen continuous 2" insulation on the exteriors but love the idea. You need to seal the foam or mineral wool up but then nail up siding & puncture your membrane but any water should flow out from behind the siding and not puddle.
Does the aluminum flashing interfere with cell service?
More than likely, yes.
It helps to keep aliens from scanning brain waves. No more foil hats to mess up the hair.
On the upside, it will improve indoor wi-fi performance/reliability due to reduced interference from your neighbours. Once you're at home you mainly care about wi-fi reception anyway-especially if your smartphone and cellular provider supports VoWiFi.
The windows allow cell service
@@circularebin 🤣🤣🤣🤣🤣🤣
What about the results for Zone 5 and 6?
Please don't.
@@cameronlapp9306 Please don't what?
Vapor closed systems are used in commercial construction in every climate zone and can be used resisdentially as Matt and Kristof indicated when properly designed.
Matt, a couple of question, not criticism: I get that , if you keep water out of the sheathing, you'd measure less moisture content in the material. My question, though, would be if the vapor open material was applied in the most tight way possible. That info might be in the report, but I haven't read it, yet. An important point to mention here would be if all the staples were taped over, because, as you showed in some previous videos, a lot of moisture gets behind the house wrap through the staple holes and not so much by vapor transfer. Also, Would an application of Aluma Flash over OSB followed by installation of 1" foil faced Polyiso foam trap moisture between the two?
Im using 7 perm in S. Florida and drying both ways. You have to build perfectly, when you use this zero perm material. I resectfully disagree with using zero perm rated WRB. 5 to 10 perm, Rockwool, ERV and De-humidifier.
@@David-gld Well, im not going to put zero perm on and watch the weather forecast every hour. because if one stick gets wet, you are screwed. Thats why Matt's friend there said, make sure you are totally dry before application. 7 perm is not terribly vapor open. Thanks for the opinion, its healthy.
Really makes since with a good air system that has a dehumidifier and a system to bring in fresh air!
Again I’m hoping that in near future that they use a konculator in combination with sensors to gauge humidity and the presence of oxygen in each room to ensure a living space that is healthy!
gor distracted with the sock puppet hands in the window at the beginning
In the simulations it sounds like moisture got into the wood structure in both tests. But how did the moisture exit the wood in the vapor closed model?
anonymous through the interior. Air conditioning for example
anonymous ... realistically, it must have dehumidification equipment, such an HVAC unit and/or a dehumidifier to maintain the lower levels, otherwise the moisture would be trapped. The only other way the moisture could escape, is via an open window or door, provided the humidity is lower outside, however, opening doors and widows could in turn, increase the interior humidity levels. It’s something that will no doubt have to be religiously monitored, because it would not take long for building materials to reach a moisture level of 20% without a means of removing the humidity. I don’t mean it would happen overnight, but moisture content typically ranges from 9-15% in a vapor open structure, so it doesn’t have far to go. It would likely never exceed 25-30% without another moisture source, but the structure would suffer from dry rot over a prolonged period in that range.
Thank you for the replies. My understanding of vapor drive is that it would be directed towards the interior of the house during the hotter months and towards the exterior during the colder months. I agree that during the summer a dehumidifier would work to reduce the moisture inside. Though, it can get cold enough in Texas to have the vapor drive pushing out towards the vapor closed wrb for at least three or four months out of the year which is long enough to begin growing mold. Im also wondering if they modeled a vapor closed wrb over exterior insulation. Would that move the cold, condensing surface away from the wood in the structure, effectively protecting it all year round from moisture?
Yes
anonymous ... that’s where the poly iso can shine, but it has its own drawbacks from time degradation. I think the main question surrounding all of this is, whether you would ever see the return on investment. People like to speak of their “forever home,” but is it, really?
So you moved the staircase after all? :P I speak German (5:02)!
more stimulus!
@@toology55 hahahahahahahaha
This isn’t his remodel
Wonder if Ploy Wall would make a product similar to Huber Zip to help save on labor costs. I mean radiant barrier on OSB exists. Then we could just tape/ liquid flash the seams. It's hard to justify the price on my low income rental builds though.
Huber has a patent on their Zip system, so unless they pay royalties or come up with something different enough to pass through expensive lawsuits/lawyers I would say no.
A friend of mine started remodeling and used Zip R and Sealed all of his buildings, cost was about 12-20% more BUT got awesome blower door numbers, and he found he could rent at higher price point AND provide heat/water in rental and all college kids had to deal with was electric and internet/satellite. Also he uses uponor PEX, rockwool , and a drywall with a noise core(basically tar/dynamat sandwich in mold resistant dry wall. All wood is mold resistant, kitchens and baths got Schluter water proofing Ditra and such. His apartments and homes are great, make ,honestly 20-25% MORE and bottom line is cheap shit dwellings get you bad things happening. He found sound dampening drywall is easier to repair as it won't cave in like regular will, I sent a screw, lay on some joint compound and pull it up straight, let dry, reprime and paint and it's back to good. His drywall repairs take no time vs replacing sheets. Again, easy fixes and no issues when something fails but it is prepared for the next needed fix.
Great video, Matt. Does the WUFI simulation assume mechanical assistance? Or is the simulation in the absence of any air handling system?
There may be some additional benefit beside preventing mosquito fly ins with an always on air circulation and make up system that maintains a positive interior air pressure. The last time I had a cold or flu was last century but that's just luck. At least the building code and the manufacturers keeps trying to get it sorted, one day perhaps?
So I am confused on one part, several years ago you were showing housing completely coating with a poly wall blue barrier, are these products used in differnt applications? Or is completely coating a house much more expensive and that's why it's not done as often?
@WinWash00 You might check out Barritech VP, made by Carlisle. It will only be available through a commercial/ industrials coatings and sealants distributor. Excellent product, with a bunch of compatible accessory products. We tested extensively, and have it in place for 8 years now. Only way to go, on complex continuous exterior insulation projects. The labor (surface prep) is the real cost, not the product. As a pro builder, the cost is not the issue, the risk exposure for not going that last critical step is the overriding concern.
👏👏 let’s talk more about venting & mold please 🙏🏼
Is this assuming you are conditioning the inside perfectly?
Is there any concern with non permeable about moisture that is coming from inside the house (showers, kitchen area examples) being trapped in the framing? Or is that so small that it doesn't amount to any problems? Thanks for another great information packed and backed up video 👍
Matt runs dehumidifiers in his builds so this negates the issue. The wall can dry internally so keeping bulk water and air out is the primary focus.
My understanding of this system is that interior generated water vapor will not condense inside the walls because the inner face of the vapor barrier, which is the foam exterior insulation, is warmer than the dew point. So the water vapor will not condense since it has not hit a cool surface. As the house is ventilated it will be flushed out. With tight houses like Matt's it is critical to have mechanical ventilation.
Thanks for the replies. School day for me
Does this simulation take into account the moisture given off by the occupants and their daily operations like cooking, (dish)washing, etc? Because that is where the big argument for a vapour-open barrier is coming from, to be able to move that moisture out. In regard to only the moisture from outside, it is quite obvious that a vapour-closed barrier would perform better as a vapour-closed barrier has a lower moisture permeability than a vapour-open barrier.
Everyone wants Build Hats
I want “build” boxers
My build hat didn't fit well, tossed it out
So that sounds like it'd be used on something like a standard OSB sheathing product rather than something like Huber's Zip System? Or could it be used in unison with Zip?
I presume climate zone 3a is close enough to zone 3
Great video!!
Matt - I live in the desert of SoCal. How about some videos on stopping heat vs. cold penetration?
I suspect the build style would be similar, but there has to be products geared towards the stopping or reflection of heat.
Thanks!!
Anyone else see the and in the upstairs window in the beginning?
Matt, great vid, love the info you provide,...Question: If building a zero (or low) perm house, should you automatically opt to install a dehumidifier? I plan to build a SIP panel house, with SIP panels that are clad in ZIP system, on a crawl space constructed of Faswall ICFs, with attic and crawl space sealed & conditioned. Also, is it an issue if crawlspace is permeable, and house from foundation up is not?
I would love to hear who you selected for that SIP fabrication as that is something I am interested in doing as well. could you post that company or contact info, I would be very grateful. Regards
What role does the sheet rock play in this analysis? Is it assumed that the stud cavity will dry through the sheet rock? Even painted sheet rock? Or is the assumption that almost no moisture is getting into the cavity so drying through the sheet rock is not an issue?
So, if you are using a wall sheathing and covering it up with Alumaflash, then a standard OSB would be perfectly fine to use, rather than the Zip panel?
The title on your graph says Tyvek
Ok so we've seen you in Canada. To cover zones 4-6 how about hitting up the rust belt states, il,in,oh,pa or somewhere in there to show us the differences. With your external insulation and wrb I really wonder how much different the details will be!
Am thinking wow wonder what the mold situation would be in your building if you did not as you mention every time you do a hvac show.. those gigantic dehumidifiers to suck the humidity out of those igloo coolers with alumiflash. I always keep in mind that houses today are a more unified system. Can only imagine what would happen in short order if you did not not add on those dehumidifiers that pull gallons and gallons of water out on a daily basis
I wonder how it works in climate zone 4?
In northern climates this would kill your building, worst thing to do. In the south with a AC removing the humidity inside probably a non-issue.
What House Wrap would you recommend for a stucco home in the southern New Mexico/El Paso area? Typical required is two layers of felt paper and chicken wire. Aluma Flash recommends Blue Barrier for every staple and screw but that wouldn't be practical. Guessing it would be similar for Delta Vent SA. Just looking for something better for air and water than felt paper. Appreciate you suggestion @Matt Risinger and others. Thanks.
I feel that no situation is perfect and when wood is involved it needs to dry period. Things fail or get damaged so imo I'd rather have my house breath.
I live where it is hot and humid outside in summer and hot and humid inside in winter. What side should air sealing be on and where should vapor permeable membrane go?
Thanks Matt for all the great videos! We live in PA and are in the process of getting our siding done so want to make sure we get it right underneath. Our current sheathing is 1 step above cardboard so we’re planning to replace with plywood sheathing. 1 question, would it work or make sense to use the zip tape to cover all seams on the plywood? Next we’re going forward with doing low-e wrap. 2nd question is for our area would it make sense to do R6 foam board over the plywood and underneath the low-e? Would this work or be overkill? The exterior studs are 2X4s. We are doing regular vinyl siding on top of this. We have electric heat pump and air and want keep our energy costs down. Any
Hey Matt, if you launch a northern version can you wear a top hat or something each time so it's easier to identify what zone it is?
Question is, how does internal humidity behave on a cold wall.
Zone 1; dry both ways, 5 to 7 perm, rockwool, rain screen strip. Bomber!! Closed cell exterior...nooooooooooooooo!!!
Answer at 8:15
How does “vapour closed” perform in the North West (Seattle or Vancouver)???
Probably not recommended north of climate zone 3, you need to dry to the outside there as I understand it.
the house will rot from the inside out.
If you choose to use this polywall aluma flash, then would it be redundant to use the Zip system as well?
How do you properly insulate block and brick home? Frame then sheathing then foam insulation then water air barrier then alumaflash then block then brick? That’s a lot of layers
Why couldn't you paint the exterior sheathing to waterproof?
@HEAV¥HAND, Why do people paint their houses, sheds and decks then ?
I love this discussion. It is highly informed and free of dogma. Every system has a potential failure. I think the upshot is, as Matt says, is that if you can guide a quality install, then protecting against wet air intrusions is best/ jumps to the top of the priority list.
Matt, are there complications with this system in your area for households that alternate having windows open with having them shut and hvac on? seems like the moisture from humid air in open windows would have no where to go... or would the a/c pull enough of the humidity out?
Does the aluminum wrap increase or decrease then signal strength of cell phones 📲..... Does it reduce or strengthen WiFi signals 🤔
That's a pretty good concern. I think it might. But if you can swing the price of Alumaflash, you can probably afford a signal booster.
Decrease. Easy to test yourself.
It would decrease cell signal. I'd just moved out of a house that just had the radiant barrier at the roofing. Inside the house, 1-2 bars of service; outside of the house, 3-5 bars. I can only image what it'd be like totally wrapped.
I hear it will protect you from alien mind probes, but you need the flashing details to be perfect.
Great show
How will this poly wall compare with the Huber Zip-System?
Thank you for this info. I do have a question here and would appreciate your feedback.
I live in PE Canada, it gets very cold and dry in the winter yet very warm and humid in the summer, what vapour application would you recommend, closed or open and what products?
Tyvek is used everywhere here but I feel there is a way better product out there.
Thanks in advance :)
I used 1" aluminum board here in Ct directly behind my cedar clap board over 25 yrs ago and no issues yet.
Typically in Canada, as a heating driven climate, your vapour barrier should be inside your insulation. If you already have a stud wall filled with batt and are looking for a house wrap you should be looking at an air barrier that is vapour permeable. While Tyvek is one example my personal preference would be a adhered system of which there are many manufacturers. I would consult a local architect with you specific wall assembly for specific product recommendations.
I agree with Christian. VP100 Blueskin is becoming pretty standard on high-spec projects, but every manufacturer makes something similar that works with the rest of their tested system. Another benefit over traditional tyvek is that it generally less prone to random rips and tears as it's tight to the house and self-sealing. It also lasts longer in UV.
From now on, any video that contains products that are not used in your house I'm going to have to ask: why did you not use it in your house? :) In a good way of course.
Valid question. I probably have used PolyWall AlumaFlash on more homes I’ve built in Austin over the last 7 years than anything else. It’s $$$ and bomber. Perfect for homes with no overhangs and high exposure
Matt Risinger
Why not in your house?
@@edcurwick8383 what?? Bruv he's standing in his house, which has alumaflash on it, in this video lol.
@@wulf9gang Not. Vid from January, a client house. Look at Matt's own: it is Zip with continuous exterior polyiso. Lol.
@@edcurwick8383 He has large overhangs, so not worth the added cost..