Superinsulating a Home With Rigid foam
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- Опубликовано: 27 сен 2024
- Excerpted from a full page article on installing exterior foam insulation at: www.greenbuildi...
A THICK SKIN THAT KEEPS A HOME WARM AND DRY
Foam sheathing can be your insulation, air barrier, and drainage plane all rolled into one.
Sheathing with foam-board insulation is a great way to get more R-value with a conventionally framed house. It can work just as well in remodeling projects as in new construction. Applying rigid foam takes some getting used to, but the basic tasks are not that much different from installing typical plywood or OSB sheathing-and the lightweight foam is easier on your back...
For more information read the full article at: www.greenbuildi...
In both the houses I built , I used this type of foam board. I nailed 3/4" foam board to the ceiling , like sheetrock. Make sure the silver side is turned up. Then nail the sheetrock in the conventional manner. Insulate the attic as always, using pinl batts. I don't like the blown stuff. The blown stuff deteriorates. Just adding the ceiling layer saves Air Conditioning, maybe $50 a month, estimate, in Texas.Costs about $800 and installs real easy.
First comment I've seen even modern times with the correct use. A better plan if you have the time is to nail it to the joist and leave a a gap at the bottom and top right near the ridgvents and now your attic will be 40 to degrees cooler in the summer which is huge considering they put our damn HVACs and duct work up in the attic which is.no longer allowed
This stuff loses its R value after a few decades. The cells start to leak pentane.
Everybody is worried about air infiltration which is great except when homeowners push out inside air in the process of drying their clothes or exhausting cooking fumes. As negative pressure increases, you're going to get more air infiltration. It would be better if appliances were installed or designed to take in outside air instead of localized inside air.
that ain't cheap, that's for sure... man, 10,000 later, you have a bona fide ice box.
Pro tip: watch series at kaldroStream. Me and my gf have been using it for watching all kinds of movies during the lockdown.
@Jon Caiden yea, have been using kaldrostream for since november myself =)
Wow i want my new future home to be insulated like that. seems like super overkill and I like it!
Where's your OSB and Plywood?
in 09 there was no such thing
@@greg925911 Baloney. It's been in new construction for decades.
@@greg925911 what????? I have been a builder since the 70's there certainly was and still is sheathing.....not sure why you would say that
They meet minimum code by installing 1/2" plywood shear panels over a percentage of exterior walls.
Looks like your guy was caulking the face of the stud rather than seam . Great way to seel the customer .
one issue is when you screw a ledge rafter to the studs with 4" of foam, you are depending on the screw for support. Not good. It should be a large bolt or go directly to the stud. That direct contact wood to wood, is a lot stronger. I get his idea but it might create other issues.
Absolutely correct. A ledge should go tight to the wood studs if it needs to carry a floor joist for a deck. Screws will bend & foam will crush over time from the weight.
My outside is done standard but I put foam under the drywall which nobody does. Only thing I’d do different is 2” foam but I did mine in ‘00. Today much more costly. If it wasn’t for the leaking around the electric plugs outside wall is 👍
"R-70 fiber"? Can you please clarify that statement? Do you mean fiberglass? If you do, how do you get R-70 worth of fiberglass in a 4" or 6" wall? Please clarify.
On the interior, can I use Thermax insulating foam and just use liquid nails to apply sheet rock directly on the Thermax foam I don’t wanna have to start out the wall
My house is 33 years old, no wood sheathing. Anyone saying you NEED OSB sheathing is totally clueless. There is more than one way to build a house.
Trust me there is osb or plywood on the shear walls of every house built.
Did you build my house? Thought so.
SkilledEddie You are incorrect. My house was built in 1956 and uses three coat stucco as it's shear. That is still code here in Northern California as I just finished building my detached garage and only used a scratch, brown and color coat (3 coat) of stucco for my shear.
On the shear walls of this house there is osb, it says so in the video.
looks like a good job.
This is exactly how to insulate a house. Their heating bill will be tiny. Amazing work
no it's not; stop lying; stop being so stupid; grow up; and figure out what's really going on and why.
@@01mustang05 whats really going on?
@@AlejoSunShine1111 wtf did we just read 😂
The foam shouldn't be the air moisture and vapor barrier. And the foam boards lack structure. From the video, it looks like this isn't done right. It should be ply/OSB, then a control layer (air and water), followed by insulation on the outside.
Great job!
Poly iso is a warm (greater than 40 degrees F ). It gets its r value at 40 degrees and higher. An r-6.5 drops to a R-4 at 25 degrees F and an R-2 at 10 degrees F. It is important to know the science behind your products.
Just a thought: wouldn’t that have to be a mean value? Like, if it’s 70 degrees inside, and 10 outside, only the very outer layer on the outside will be 10. The rest will warm heading inward and increase in r value.
@@timgleason2527 correct.
@@timgleason2527 i don’t believe it will be 70 on other side of poly. Believe that poly will be closer to 40 when you touch your 6” wall
@@superdinmt True! Though maybe your 6” wall. My 4 inch half insulated wall is nearly useless. 😂
@@timgleason2527 lmao.
What are your thoughts about using closed cell spray foam in the cavity to help increase the strength of the walls with the added benefit of insulation? Down here on the Gulf coast, we need that extra strength for hurricane winds. That's if building with ICF, concrete, SIP is out of the question
Closed cell spray foam is great because it seals and insulates. The structural benefit is good but is no substitute for hurricane straps at every angle. Houses in the Caribbean islands get leveled despite straps. Poured concrete is the only thing that holds up. Also, termites don't eat it.
Just wondering, if you tape the joints on the insulation this will cause a vapor barrier,hopefully your not going to insall a vapor barrier in the interior wall.thats a no no house needs to breath. just a thuoght
mexifin Do lots of research on this. Houses don’t actually need to “breathe” that’s old code from a very long time ago. Air barrier, vapor, thermal, and water barriers go on the outside with ventilation up to the peak. Lots of research over many years in all climates were done to achieve this result.
Many shops are air sealed tested for leakage.
What happens if there is a fire and the iso-cyan-ate breaks down into cyanide while the family is asleep?
what a JUNK HOUSE - NO WONDER everything falls apart with you guys with even the smallest earthquake or calamity! :) ahahah
Nah, America has the strongest building codes actually.
What about possible moisture condensation between two layers of insulation. Why not use single thicker sheets?
Is that shiny side a vapor barrier? I have two questions: 1. If it is a vapor barrier, why is it facing the outside. 2. Why is it doubled up which might trap moisture inside right?
2 vapor barriers and no it does not trap moisture.
does it not make the structure weaker if osb is not used?
Absolutely if no proper bracings are used.
Insulating the Shite out if that house.
Do you then nail or screw the siding directly to the foam? What sizes work best? I did something like this by putting 2inch foam on the outside then I screwed a thin layer of plywood to the outside of that to have a base to nail in the siding.
What rigid foam radiant barrier are you using? Thnx for the vid.
Awesome!
what keeps the house square, especially during a fire?
If there's a fire, are you really going to be concerned with a square house ? lol
They cyanide the product creates
@@augustreil Not sure if you know this.... but firefighters go into burning buildings. Its shocking, I know.. If a house doesn't have lateral support, it falls down!
@@natasharobichaud, No ? Really ? lol
Well I appreciate the answer, but it sounds like' you're biased against spray foam, and no one can convince you otherwise so i wont argue on that. But your're suggesting all the southern and eastern states, bordering the Gulf coast and Atlantic coast should just pack up and move north? A hurricane doesn't just hit the coast you know, they do move inland. That's the same as saying people shouldn't live in tornado alley, or near a fault with many earthquakes. So where do we live?
@HomeEnergyNow yes , the blown insulation deteriorates into dust. If you are promoting blown insulation , it must mean that you make money at selling it. Batting does not lose it's R value like cellulose does. Do you build houses , or just sell crap to builders?
Wait till the wind blows. I think I could push this house over.
You're on crack.
august === There is no integral strength to the wall structure...I am an engineer and find it hard to believe this would pass building code anywhere... Foam boards and drywall on the inside do not give enough lateral strength to keep this house from being warped out of shape... Maybe thats why there is no videos posted after this house, a full 8 years ago. .I hope someone an give google coordinates so that we can see if it is still standing...
@@DocScience2 They meet minimum code by installing 1/2" plywood shear panels over a percentage of exterior walls.
Would have been stronger and just as cost effective to osb/ply the exterior, wrap in a reflective media, and fill the wall cavities with foam (or just build with sips for an even better structure). Your dime, your time!
filling studs with spray foam and adding a "reflective media" will not eliminate thermal bridging as the design in this video does. SIPS will though, as you stated, and they go up quick! I still like stick build though... :-) Buts its more emotional than rational.
This a long time ago
Not the best way to get R value, also this insulation is NOT green.
Really? This is the best way! Prevents all thermal bridging. As long as you don't use it as the vapour barrier as well, the more insulation you put to the exterior of the studs the better. You benefit from 100% of the R value
@@jasonwhittaker6243 no it's not; stop lying; stop being so stupid; grow up; and figure out what's really going on and why.
Anybody have any experience with this stuff to know the fire risk with it? No wisenheimer responses please. This is a real question.
Why don't you build your homes out of mortar and brick?
Blunder1248 Americans??
Capitalism
I wasn't born yet on this
It's Adam Sandler's less famous but funnier brother.
If only this was code in america, rather than the exception.
It was junk then and it still is.
air movement is what moves moisture OUT of your house... these house wraps, sealed foam, and vapour barriers are what rots your house framing and creates mold issues.. this new "environmental" buildings are built exactly wrong..
+Erica Moon I build to code to make money and that is the reason I will no longer build a home for myself.. not only do I build new homes, I repair and renovate old homes and I've seen exactly what is causing rot and mold.. however, I live on the west coast of Canada and have been here my whole life so building code requirements that do not work well here may be fine in other climate zones... I have no experience in those areas
do an experiment.. put a few slices of bread in a zip lock bag and put it outside in the sun.. you will see the heat evaporate the moisture in the bread and it will condense as water drops on the inner surface of the bag and where the bread makes contact with liquid water drops it will become soggy.. if you put a few slices beside the zip lock bag they will not get soggy because evaporated water will blow away in the air.. moisture content of wood higher than 20% will start the rotting of most types of wood used for construction.. a drop of water that was formed by the natural moisture in the wood (7-14% average) evaporating then condensing will make area of wood it makes contact with WAAAAY over 20%, it will likely be 90-100% and will start the decay.. the only way to stop that natural decay is to use air movement to take the evaporated water away and let the wood dry out..... sealing the hell out of your wood with plastic and foam prevents evaporated water from escaping so it will condense back to liquid and stay.. this idea of keeping moisture out by sealing and taping is a fantasy because wood always contains moisture.. the rot can happen without any "leaks" as the majority of lumber is 14% moisture content.. that means the amount of wood to fill a 10 gallon bucket has 1.4 gallons of water in it... if it remains equally distributed in the wood it is fine, it it evaporates, condenses and runs down the plastic and forms a puddle at the bottom of a wall the wall will rot..
+MrMeanderthal If you are doing an energy retro fit and your house has a vapor barrier on the interior drywall side, would that require yanking out the interior vapor barrier to then put the exterior foam? I am trying to think of a way without having to completely redo my exterior wall setup to make my house a little warmer during the winter.
+KingCaravaggio I'm doing a reno now that is a house built in the 50's.. I took drywall off inside and added 2" strips of wood to the 2x4 framing.. it is now the same width as 2x6 and will have same R-20 insulation as real 2x6 framed wall.. what is standard now for 2x4 wall is R-14 but back in the 50's it was only R-12.. now the new R-20 is 40% better R value than original that was removed.. it is not the perfect way but it is much cheaper than redoing exterior as well (removing siding etc)... one has to consider the energy cost saving compared to the cost of improving insulation... here on the coast of BC I would not put 6 mil poly vapour barrier in if it was acceptable but by code it is not so
I will be putting it in before mounting drywall.... I am increasing R value of insulation on ceiling and using 3" rigid foam to insulate interior of concrete foundation and rim joists.. that will mean insulation starts at ground level rather than bottom of wall.. I am also covering the dirt/ground inside foundation with 6 mil poly and then 3" rigid foam.. all together than will make it a lot cheaper to keep warm..
If you have moisture in your house you have problems. Where is this moisture you are talking about coming from? A vapor barrier is used on top of the sheathing so if you have moisture inside your house you better fire your plumber not the carpenter...
vapour barrier is inside behind drywall.. it's not outside overing sheathing, that is called house wrap... the majority of moisture that gets into your house is from air humidity and from things like showers, sinks and boiling water etc while cooking......
how in the world do you get any sheer wall strength form this method?
T bar metal straps
So, are we going to break open a window or jimmy the door to rob this place? Na, just cut through the wall with a utility knife
Do you still have to use plywood and house wrap prior to rigid foam?
This is what I want to do with a very lousy insulated trailer. And I want to put stucco over that. Yes, 4 inches of foam if I can. I experienced 25 F below my first winter here. Brrrrr.
+whisperingsage Its R6 per inch so that would be nicely insulating. Pricey though 4x8 sheet 2" thick is $32 at Home Depot.
This is a lightweight wall & will not provide much soundproofing. OSB literally stinks when used indoors. A 1/2" plywood wrap attached to the studs will add the structural racking strength against strong winds & will stink a lot less. Without plywood, the wall needs special framing methods. This is polyiso which is R-6.5 per inch and has better fire resistance and rigidity than polystyrene foam board. Polyiso is used for walk-in freezer walls and is a great insulator but the foam soaks up water vapor like a sponge when the vapor barrier is broken. I have experience with tear out of walk-in freezers and a 4" thick 4' x 8' panel will hold 100 lbs of water. The vapor pressure difference between the cold side and the warm side drives water into the foam. The polystyrene foam board will not absorb water so I think it is a better product when installed as a wrap but it has no fire rating. I recommend using 2 x 6 studs with 1/2" plywood sheathing & 2 layers of 2" styrofoam tongue and grove. Inside, sheetrock 5/8" with blown-in cellulose insulation in the stud cavities. Cellulose has better R-value, outstanding fire resistance, better soundproofing, and built-in insecticide. Fiberglass batts don't do anything as well. No other vapor barrier is needed. Any building insulated like this must have positive fresh air ventilation and in hot climates, a whole-house dehumidification system.
Mineral wool is on par with cellulose as to all of its properties. And mineral wool batts are easy to install without equipment.
The borates used in cellulose and mineral wool contribute to fire and mold proofing and insect resistance. Each perform well for sound reduction too.
When you say or write that... "The vapor pressure difference between the cold side and the warm side drives water into the foam" - you mean the water vapor difference drives water VAPOR into the Polyisocyanurate foam, which later condenses into water, in which the PIR foam retains? I've read that PIR is a closed cell foam too; so with the two sides of foil (being vapor barriers) and the closed cell foam (which also is a vapor barrier), I don't understand how PIR absorbs water or water vapor and holds it. are you sure the freezers you've had experience with had PIR in them?
@@01mustang05 The temperature difference is the key. The higher the temp the more water vapor the air can hold. In HVACR its called vapor pressure that allows water vapor to push from the warm side through the insulator to the cold side. It's a molecular movement and does not depend on air movement. Does closed-cell Polyisocyanurate foam soak up water vapor? That's a good question. Foamed in place closed-cell polyurethane is used for refrigerator/freezer boxes. Isocyanates are used to make polyurethane so I am equating both PIR and PUR as the same. Yes, I think PIR is just as permeable as PUR. A perfect vapor barrier is needed but unlikely to be achieved with thin foils. As a refrigeration contractor, I have also used rigid urethane pipe insulation for walk-in freezer lines and it failed because the warm humid air seeped in at the insulation joints and water/ice formed inside the insulation. I started using Styrene foam pipe insulation and what a great difference it makes. Yes, the polystyrene must be 2.5 times thicker for the same initial R-value but it stays dry and will keep its r-value at low temperatures (high vapor pressure). There is a huge loss of R-value with just a 10% vapor content. I had to study all this in my refrigeration engineering school but it was a long time ago. Fiberglass and rock wool are the worst for retaining water vapor and its why they were abandoned by the refrigeration appliance manufacturers as soon as urethane foam became available. There is a great debate on the value of a vapor barrier in home construction. The current agreement is that excess water vapor MUST be removed from inside the house & excess water vapor MUST be blocked from entering to the inside of the house. What is excess ... an average relative humidity over 58% @70'F in a 24 hour period. Mechanical ventilation with active dehumidification for the indoor climate is the current best practice.
Love your idea. I believe that is what a house needs. I am wondering what to use to attach 4 inches of foam. Very much doable on 2 inches with nails. Not sure if there are 6 inch nails 🤔
I guess screws would work great. But then there is the wire and the black paper. Wire holds the paper but the wire?
How would you attach the wire 🤔
Stucco wire and metal lath?
@@01mustang05 Yes it's closed cell and I have direct experience. I used it once for a pipe insulation job and I thought like you that because it is closed cell it would be waterproof. It failed after 4 months. There is no vapor barrier that is air-tight forever and the slightest hole will, over time, let humidity-laden air seep in. It depends on the temperature difference and once a little moisture forms inside the foam it creates a cascading failure. Damp insulation loses 90% of its R-value. The insulation industry should better educate the building trade about the limits of board insulation. A Coleman cooler works great with this foam sandwiched between thick plastic because it's a hermetic seal.
I don't like polyiso foam because I am allergic to MDI. I don't like the lack of plywood for strength. I know it had a few pieces for sheer loads, but I would prefer a stronger house.
I did an addition like this with no sheathing.. what a mistake.... shitty job... always use sheathing....
I know this post is 12 years old but they still build houses like this. mine is about 80% with the garage and a few walls of the house only tyvek and insulfoam. It meets shear codes in california but I still think its shitty on the builders part. most new home owners are too dumb to know how their homes are built.
That's a Mickey Mouse house.
Ikr
Years later, 2023, here in Canada we have to have sheathing directly nailed to the studs and only then is rigid foam, or rock wool, added over that on the exterior. We need that sheer strength so ply or OSB is a must. Bravo for paying attention to detail! 💯👍 🇨🇦
@HomeEnergyNow hahaha.I build things to last , and energy efficient..You build to get in and get out quick..No matter the number of bags, that blown crap packs down and loses it's efficiency in a few years.Batts keep their R value , long after your stuff has turned to dust. As long as you can fool people, you will have a job installing and refilling later.Let's just say you win the youtube battle.
I was afraid to put spray foam on my inside roof with out a air gap between the insulation and the plywood. The poor man's foam board was the answer to my problem. Thanks
You guys arguing in the comments about what is better insulation crack me up. The real problem here is that these houses are built out of sticks and use thin boards and tape to create air seals. I'll stick with concrete, thanks. You can keep your toothpick houses.
I can't tell if you are being sarcastic or not. Concrete is expensive and has an enormous carbon foot print. Wood is renewable and far cheaper. ICF walls are nice but again come at great cost (to the buyer and the environment). Unless I was super rich and lived in hurricane country, then I will stick with stick-built.
Third world country moron!
Jonathan Masiello what concrete you mean walls made out of concrete and ceiling made out of concrete and floor made out of concrete what's your frame?
SIP panels is the way to go
Jonathan Masiello u
Insulation used as a wall, no thanks. And is that stuff foil faced like polyiso? That means vapor-impermeable, which is not great for "breathability" for the home.
Homes should never, ever "Breathe". Breathing implies letting air through. For a home in winter, this means letting warm air through and increasing heating bills, etc. But, I think I know what you meant and you are correct. You were referring to the need to dry by letting vapor pass through the wall assembly. Polyiso this thick is definitely vapor impermeable. But, as long as there isn't any poly (polyethylene, that is) on the inside, as is/was code, then the wall should be able to dry to the interior. An interior smart vapor retarder might help keep interior moisture from entering the wall as well.
As long as they have some horizontal bracing for the studs, this is a good building design. Plywood and vapor open Roxul board would be a better choice but it is more expensive.
Cougar Land, you want to be able to control your ventilation and heat exchange to the outside. Only an idiot wants holes in the exterior walls.
I put 1/2" foam on inside of the exterior walls n drywall over. Appears to have been noticeable improvement. Should have been thicker but need some help with air quality regardless. I was under the impression that insulation holds the heat in so I did it.
Scott Seems like a good idea to me. So, did you leave the traditional insulation in your walls? I imagine your heating/cooling bills went down right? I've thought about doing something like this, and also do some rewiring while the walls are open. And the last step would be putting up foam insulation on the ceilings, interior side of the attic. Don't know if people do this or if it would even help, but I think it would work. I live in the midwest where we see winter temps between 2 and 50 degrees and summer temps of between 70 to 100.
what type of foam did you use? - open cell? - did you add a vapor barrier that still breaths a bit or not at all? closed cell foam? - did you omit a vapor barrier and use the closed cell foam as an unbreathable vapor barrier?
Troy Barnes I think it depends on what ur need is. I live in central mn it gets-30 so I wanted to keep my heat in. I still had 2x6 w/fg n vapor barrier. Too much ? Really wtf knows. It was new construction 20 yr ago.
Some one I h used the foam in addition to the 2x6 n vapor barrier I used Owens Corning 1/2” pink closed cell. Sorry I didn’t go thicker. I also put on cathedral ceiling. B careful about screw length needs. I’m in cen minn it gets -30 so I wanted to keep the heat ln but needs are according to.
tHanks for the comment Scott. I have two different uses in the works. One is adding polyiso to the outside of an existing house. I made a video asking for help with advice there. The other is to use 1" foam over the studs and under the drywall. To fill the wall cavity with unfaced insulation and have just a housewrap on the outside. Mid Atlantic Humid area. So those crazy sub zero temps don't visit us often.
Installing inside is very easy...step ladder at the most. The drywall hangs nice and straight over the foam. Meanwhile, these days many people are insulating on the outside of the home.
So I turned to RUclips for help by posting an SOS video. tHanks all!
@HomeEnergyNow Do everyone a favor and take a nap on the railroad tracks
How healthy is doing foam insulation just to save a few bucks on heat? If your house doesn't breath then your air quality suffers indoors.
jim Bee very true... You have to have airflow. It can lead to mold too.. And mushrooms in the wood.