We so need some videos on taking an attic like you had at the beginning and having it converted to a conditioned attic.

This is a valuable addition to my woodwork collection kzfaq.infoUgkxbnOKZBE4evMO5V2vroHeCjq6d_MV6wJO I still will rate this woodwork plan as the best in my reference library. It always seem to stand out from the rest whenever you go through the library. This is a masterpiece.

Im a HVAC TECH in south Texas and those conditioned attic spaces are lovely

Here’s the issue with unvented attics. The home will self destruct in the absence of electricity (unvented attics REQUIRE air conditioning underneath constantly). Many homes in Florida that either went without power due to hurricane or foreclosure filled up with black mold. Most had to be stripped to the framing to repair. A vented attic is self-drying without power so for our off-grid ready home an unvented attic would have been a horrible choice. I like your videos but when you omit all the cons while touting the pros it seems like a sales pitch.

Consider maybe a vid on how to convert a vented attic into an unvented conditioned attic?? If that even makes sense 😆

Having lived in a Texas home with a conditioned attic I can confirm it is an order of magnitude better than conventional. It was proven as my neighbors had conventional with Identical builder. I opted to spring for the initial $$ up front. Result? My heating/cooling costs were 1/3 my neighbors with same size homes (2500 sq. ft). No Dust, no bugs, super quiet, and no dread when handling things in attic. I can verify also the cost upfront was easily offset by energy savings, and no doubt made my home sell at a higher price than comparables due to my ability to prove energy costs based upon actual bills. I will never live without a conditioned attic ever again.

Amen to the importance of a sealed attic, Matt. When I insulated mine, nobody wanted to believe me that it was going to be 75 degrees in side with 100 outside. Got the proof today! 101 outside, 71 inside. During the manual J calculations I had to argue with the engineer that I wasn't going to have 40% energy loss in the attic because all my ducts were in the conditioned space. And because the attic is my return air "duct" that saves even more energy. My A/C guy and I decided to downgrade from a 5 ton unit to a 3 ton after he saw the results. Thanks for the great videos. Amazing what one can learn!

I really like what I saw in this video. Very neat technology. I also like that you thought about the fresh air needs. I would not have thought of that need, but should have since I grew up in the days of the gas space heaters. As a former volunteer fire fighter, no or at least less smoke is a big deal. Current trends are to cut a bunch of holes in the roof to let the smoke and heat out so you can see where the fire is. In a house fire with someone trapped, the firefighters had to back out when the FLIR camera showed the temperature at 742 degrees, roughly 4 feet off of the floor. The trapped person didn't make it. As the fire captain said, "no one survives that kind of heat". The open core bedroom doors just went whoosh and only the frame was left. This was a 50 year old brick 3-sides house with typical shingle roofing. That was the problem. With the room temperature that high, the tar on the bottom of the shingles melted and dripped through the sheeting, then burst into flame in the attic - making the temperature that much higher. Once they got the attic temperature down a little, they were able to go in and pull ceiling to finish the lowering of the temperature. The whole thing was out in about 5 minutes after that. As a result of the SMOKE, the city inspector required that the left overs be taken to a special hazardous materials dump. The smoke alone caused everything to be classified as hazardous. If your house catches on fire, please remember what we taught you in elementary school, get flat on your belly and pretend you are an alligator then crawl out. Don't stand up! Your lungs can't handle the heat or the smoke.

Up in the nothern states at least near me its called a hot attic because it's heated in the winter

having been raised in Florida all my life I would have to say this is the best idea I ever saw on building an attic the right way

My attic used to go to 130F in summer. I had spay foam installed and it rarely reaches 90F. The electric bill has been reduced by about one third. But the more important thing is that the AC cools the house much easier. From Atlanta… the other benefit is that the attic is much more usable because you don’t temperature extremes. My attic is floored so it’s like adding extra rooms to the house.

Remodeled a 3 apartment house using only rock wool as insulation for both temperature and sound. Worked wonders, afterwards you could not hear a sound between the apartments while before you could understand any conversation that was above a whisper. Not only is rock wool wonderful to work with, it's not itchy in the least. And as a bonus, it also acts as a fire barrier.

Keeping it 100% real, I’ve been doing contracting for years now and I can’t even imagine customers wanting to spend all that money. 4” of close cell your looking around $5-$6 per sqft depending on the area and each bucket of costing is $300 each. In Texas you do not need 4” of close cell at all. In Canada we’re temperature goes under 0 use 3”. It’s amazing what their doing but way out of the budget of average Americans.

I used radiant foil OSB when I built my house in SoCal, the attic was 20° cooler than the outside in 100°+ days. Well worth the additional cost.

A few years ago I re-did my attic in probably the largest home improvement project I will ever do lol 1950s house, and the attic was finished in the 1970s, and the thin drywall and cheap wood panneling was falling apart, and it was always hot/cold up stairs. Gutted everything except the framing, then added a spacer on the roof line, then a radiant barrier, then batt insulation, and then thick drywall. It changed so much! Still need AC units in the summer, but much smaller units keep up well even on medium where we used to have much larger units on high all summer. Things are quieter, cleaner, less humid, and everything is working really well. Next step is figuring out something for the AC/heat up there. Heat rises, and that is the only place to escape to, so it stays comfortable in winter, but there is a lack of air flow/exchange, and during the summer AC is absolutely required. The rooms all have HVAC supply vents... but no returns. Our HVAC is from the late 80s, and it is kind of a miricle that we havent had any issues with it yet, so we are saving up to replace it as the next big home project... that that will be a doosey, but I wont do that one myself. Hoping to move the HVAC to a different location in the basement (what use to be a garage that is walled off), and re-route all of the supply and return vents in the whole house to make more sense and work better. Should be the last step of 'functional' changes to the home before we go nuts with purely aesthetic changes to finally make our old 1950s wrecker look as nice as it feels to live in since I have done so much work on the electrical, insulation, and water management aspects of it. We have the biggest home on the street, and the lowest power bill, but we keep the house at 70* year round while most neighbors keep things at 75 in summer, and 60-65 in winter. Been a lot of work, and it is nice to feel results. Cant wait to make it look nice and 'see' the results.

The biggest practice change is trusses vs rafters. Newer houses use trusses because they are faster to install. Most people who can afford on site cut rafters do so for the extra attic storage space.

We have an unvented attic and it has its ups and downs. live in california and out attic never gets above 85 degrees even if its 110 outside. Now this is great during the winter cause it really insulates our house and inside will never drop below 65. However during the summer after the long hot day and when it really cools down outside it takes forever for the inside of our house to cool down even if we have a lot of windows open. Its like a greenhouse effect and the house doesnt cool down until the attic finally cools down.

Building a conditioned attic is essentially adding more square footage to your house. I can tell you right now, if I was going to spend the money to finish my attic like his, it better be livable like a second or third story, not just a comfy space for duct work.

Looks great. Here in South Texas we look at all things depending on budget. So we use radiant barrier sheathing with a combo of poly to keep attic cooler while staying in a decent budget.

In England, a 'conditioned roof' is referred to as a 'warm roof'. In colder climates (colder than Texas is most of the time - but maybe not MUCH colder) it's vital to have a vapour control layer (VCL - usually a membrane) on the warm (inside) side of the insulation so that moisture-laden warm air cannot move from the living space towards the colder outside, which would result in interstitial condensation. This is ruinously damaging for out of sight woodwork. What we learnt as householders doing a retrofit conditioned roof was that most roofers knew less about this new constructional method than we (who had taken an interest) did. They, being used to loft spaces being ventilated, just did not 'get' the importance of the VCL....which is very tricky to implement properly at abutments and penetrations. A warm roof, as Matt says, is brilliant - but it has to be done right.

I think what would be even better would be to build a house around this house and then condition that house as well as the original house so that the power bill on the original house is lower

Ken is great. He really knows his stuff.

I unvented my vented attic 10 years ago with 4" of hi density foam. It has been great. I don't get blast of hot air when the A/C comes on or freezer air in the winter. I do not use my attic as storage so no paint needed, To convert, I fashioned solid foam blocks to stuff over the outside walls to spray against. Just sprayed the bottom of the ridge vent as the opening wasn't very wide. I would have used something like zip tape if I did it now. I can work up there any day of the year. It is only a couple of degrees from the living space below. The leaky roof is not an issue. I have a metal roof and even if I didn't and I let the roof go for 40 years, I could just resheathed the roof over the existing plywood. I live in upstate NY and did this when the old experts said it was a mistake, and now today it is the preferred method.

By rerouting some of the vents and piping you could make extra bedrooms or a large hobby room in the attic. This has become quite popular in Scandinavia with attics and basements, often making enough space for a studio apartment.

These building methods are going to be really nice for high ceilings in open living spaces, giving the R value it needs while making the interior a georgous space to look at... I really like the idea of having a conditioned attic for storage too!

Matt, love you videos, but for most people / builders, spray foam insulation will remain a pie in the sky scenario due to its high price. However, I do think LP Techshield + R13 or R19 in your roof rafters with a 2" air gap would be sufficient for an "upgraded" home in terms of its attic insulation, IMO. Then, get your ducts sealed /& stretched out really well over your ceiling joists with blown-in insulation over them. Finally, make sure your HVAC unit is in an insulated room / closet and add a QuietCool attic fan that operates at 70 to 110 watts to remove any excess heat. Good ventilation is also key, of course.

Great video. It's always important to talk about designing safety into a build. Would love to hear more about some of the costs associated with the types of insulating and conditioning strategies you prefer, from foam to intumescence to that zender.

I'm glad you mentioned that zender thingie at the end because I was really wondering about how air exchange is handled. Because otherwise a really tightly closed up building is going to have a build up of CO2 and get uncomfortable fast.

Here in the UK with our wet climate that spray foam 4:56 is deadly to wood beams in the roof. Do not use spray foam like this in a wet climate. We bought a house which had it done 5 years prior and I could crumble the wood under the foam with my bare hands. We were lucky the roof did not cave in on us and we had to replace most of the roof in the end. What happens in a wet climate is the water soaks into the wood throughout the year but especially during the winter but does not get time even during our "3 month summer" to dry out fully. This is because the spray foam first of all allows the water to pool and collect in between the spray foam and the wood but also prevents the heat from the house from getting to the wood at all which helps dry the wood. In a wet climate stick to rock wool or glass wool insulation if you want your wood to last. I think I would even be hesitant to use spray foam insulation in Texas without creating space for the wood to breath. Let me know if 5 years how it held up.

That's what my attic looks like, but I'm further up north, and my ducts are in the basement. We had a water leak with our roof and if anything, the fact that the attic is properly vented is what prevented further problems (by allowing everything to dry properly).

During a week of measurements in Mid-June, 2021, my 'traditional' attic in Spring, TX (North Houston) averaged 4 degrees hotter than the outside temperature (measured in the shade). The max differential was 9 degrees at 7 PM. The temperatures were measured from 7 AM to 11 PM. Mid-afternoon outside temps were 95-96 degrees. There is radiant barrier sheathing, ridge vents, continuous soffit vents and one solar powered Attic Breeze exhaust fan in the attic space.

I converted my attic from poorly insulated & vented To a fully insulated at the decking. Vacuumed out all the cellulose and fluffy white. HVAC and ductwork all inside conditioned space. I included a dehumidifier into the air plenum. Very comfortable easily keeping relative humidity 48-55%. 1600sq ft with a two ton 2stage split system easily keeps house at temp settings of 72-74. Even when temps are well above 100degrees. North east Texas area near Tyler.

You should definitely cover the importance of having ERV in a sealed up house. I’ve heard a few stories of people sealing up their house and ending up with unsafe accumulation of carbon dioxide because there is no fresh air coming in, which can have serious side effects.

The thing I appreciate most about this video is how serious this man takes his foam, his job, and the willingness to spread his knowledge. It feels like it’s getting harder to find people that take so much pride in their livelihood.

In the north where I live we have lots of "Cape" style homes... for the un initiated; a cape is a ranch or salt box 1 bed 1 bath home on the main level that has stairs to the attic which is pitched as an upside down V more or less... Not leaving much in the way of useable headroom... Most of these get Dormered out or expanded to create more space and add a bathroom... Slap up some sheetrock & fiber batt. Call it a day.... Toss the kids bedrooms up there and call it a 3 bedroom house..... In the summer the space is near un liveable. The added moisture from an extra bathroom and the fact that most people don't understand how thermodynamics works.... Mold and saggy sheetrock is common. When it's conditioned since it's not a sealed space you can imagine the outcome.

Love my ICF house with my sprayed attic, cool enough to keep Christmas candles in the walk-in storage up there, and I don't get that initial blast of HOT air when the HVAC unit kicks on.

I have seen some building science discussion regarding spray foaming ducts that are located in vented attics. Essentially bringing them within the envelope and preventing air leaks. I think this might be a great option for existing homes.

If you're looking for any existing houses to do a conversion to unvented attic on, I'm in Round Rock and would gladly volunteer as tribute.

Purchased our retirement home (built in 1947) - roof is currently a mix of normal pitched roof and some flat roofed areas. Will be installing a brand new metal pitched roof where trusses will be built onto the flat roofed locations so that all the roof angles are same-same (rain gutters to water barrels for gardening needs). I'm thinking the DC315 spray foam would be the best option for the new roof trussed areas. Would love to see a retro-fit video of an older house being updated with these new insulation techniques.

I cant thank you enough for these videos Matt!

Would like to see a video about attic encapsulation where you use the reflective radiant barrier and air sealing everything between the attic and the conditioned space, to include using insulated light covers. It isn't nearly as expensive as this conditioned method but still works many times better & accomplishes the other benefits over the traditional method you show at the beginning.

Back in the day, insulation in direct contact with roof sheeting was a no-no because the shingles get too hot. A space for passive venting kept the shingles a little cooler.

Thats a thing of beauty. It's like theres a right way and a wrong way of doing things, and most of the industry does it the wrong cheapest way possible.

wow thats just amazingly beautiful.. hell i could live in that attic

As a non-trades person, but an enthusiastic home owner, I’ve always thought our traditional attic build methods was very underwhelming and both the sheathing materials and roof insulation always just made more sense. Thanks Matt!

Nice to see that the US is slowly adopting the standard we have had in Germany for 20 years :>

I did an addition in 2008 in upstate NY and wanted foam in the walls and roof deck. I never understood having outside air flowing thru the attic. I spent numerous hours talking to manufacturers, vendors, contractors, and installers. No one could/would give an answer. I went with a closed cell foam and have been quite happy with the results. One thing I worried about was the closed cell being non-porous and would hide any roof leaks but so far I haven't seen any signs of damage. I had the contractor run ice/water shield on the whole roof for peace of mind. I do find that carpenter ants love the stuff. I do not believe it is moisture related as I poked around the area and see no signs of water infiltration anywhere around or below the former ant home. One regret is I didn't have the knowledge at the time to use a radiant barrier on the roof.

One day, when I have a good paying job, and am ready to own a house in 10 or 20 years, I want to have the home built brand new, according to the specifications I want, I'm going to hire you for that project, I've loved all of your projects!

You need to be able to put your model railroad up there too!

I’ve seen some SIP construction that didn’t require any vents and a small hole allowed for environmental exchange between upper & lower. Fantastic insulation by the by.

Great content Matt. I also went back and watched the Zehnder video.

I love that ERV system and DC13 seems like amazing stuff...

When I hit the lotto Matt will be building my next home

Thought about doimg spray foam for my tiny home...pretty sure after needing to spray paint...i think i'll just do traditional insulation.

Haha that little chuckle while mentioning a retrofit to a sealed attic, I'm sure Matt was thinking of his own project. Basically have to go down to studs to accomplish something like this.

0:24 Hot, that’s an understatement if ever Matt. Live in Central FL and gotta say, when doing a project and time to get into “attic” crawl space…..we do rock, paper, scissors….or draw straws; no joke. Last thing we wanna do during the wonderful “summer” season here in Florida (or what we call it, “Hurricanes, hot, & hell season”) is have to go into the attic/crawl space and do work. Even makes it worse if gotta gear up with PPE🥵🥵, it’s so bad. The pic here is pretty much the typical style, but so much worse for most houses around “us”. We do get lucky once in while and find an attic area where can actually “stand” a little, and move some what around; compared to the normal slithering on stomach and crawling below rafters/framing, NAILS, ducting, and so on. 1:29 [We] all need to start building houses LIKE THIS; as it’s SO Much better, imo. Can actually have access for repairs, running a wire or something etc…, walking and standing up, and not dying of heat exhaustion…. This is such a beautiful attic 😢, so Beautiful, that wish it was My House. Great Vid, and can’t wait for your hidden door vid of your “real remodel”, as love all your hidden door vids; and b/c if your channel, started using Sugatsune and Soss hinges for doing our own “hidden doors”👍🏻

From an energy savings perspective it’s great. From a termite perspective it’s awful! Currently we have been advised not to fumigate houses that do not have ventilated attics. Additionally I’ve seen homes where termites get in between the foam and the sheeting and do tens of thousands in damage before you know.

Watching this video, reminded me of old “This Old House” shows I used to watch with my dad when I was a kid. But I think these videos are better! Thank you for these great tips and information!

Great stuff Matt!! (Totally not making a spray foam pun. 🤣) Even got the wife to watch! 👍

I used to live in Albuquerque and after our roof was redone I went in to clean up and install new insulation (pink stuff) My husband put a heat sensor up there and monitored the temperatures on his computer. I believe it maxed out at 140 degrees. In summer, the ceiling was like a radiator. We had attic vent fans but because the house was L shaped it wasn’t too efficient. As well, the fans were pretty small and wimpy. And unfortunately, they will pull in lots of dust and pollen.

Show us some FLIR video of these attics on a hot sunny day.

Great video as always. One thing I'd be interested in when it comes to spray foam is those horror stories of foam that never "cured" and are off-gasing some horrible fumes that makes the kids allergic and sick. It would be interesting to know what has been going on in those cases, and what they did wrong there, and how to avoid it.

What an awesome way to build an attic!! Insulating the rafter area instead of the ceiling keeping attic and sealed I love it. Its beyond cool!!! 👍👍 and with that rock wool insulation you dont need a thermal barrier wow.

That coating is amazing!

Love the idea of a conditioned attic, I just wish there were companies out there that would convert existing attics to conditioned attics. Building a new house isn’t a solution for most of us.

I would hate to be the roof that might have to replace bad roof sheeting if a leak forms. That spray foam seems like a good idea, but its makes changing out bad wood a complete bear to replace.

Mate i wish people in aus thought out stuff like this it would make such a big difference in new houses! I am currently in the process of sealing up my garage to avoid heat loss and keep the house cool in summer

Old time builder here. With the USB roof boards if there is any leaks your roof is shot and it's hard to tell with foam sprayed on your Attic ceiling. Another thing is the cost in residence your homes 1800 to 2,000 square feet the cost increases so much that people cannot afford to buy the home. In most cases houses that small do not have much storage in the Attic anyway. Pros and cons to everything.

Aww bless, the Americans are finally getting close to learning how to roof a house properly. I love it. 👍🏻

I’ve done the same thing with batts and I only use spray foam if it’s the only way to insulate the particular job or if the client insists. The jury is still out on what happens to the plywood that’s above the insulation if it has no air flow or if it’s sealed on the cool side as with spray foam. That’s why I prefer batts up against the roof deck but with fluted baffles connected on the down side by a vented soffit and on the upside by a ridge vent. This allows some air movement between the insulation and roof deck thereby reducing a little bit of the heat build up. Great video but I might add too that the depth of the trusses will determine the depth of your insulation in turn the R value of the insulation. The video shows R30 therefore you’d need a minimum depth of 10” to allow for R30. This would be a special order truss if you’re building new or you’d have to fur down the trusses. Great video Matt. Keep em coming!

Learning never stops with your channel

Awesome info. Thanks so much.

Why aren't you using "saddles" on the flex duct strapping? You know that over time the web strapping will crush in on the flex ducting and restrict the air flow.

Matt, a cost comparison would be very helpful for you to include in this video, the cost to do the older type of vented attic vs this new type of conditioned attic you showed us in these 2 houses.

Thank you for sharing!

wow...jjust looking to convert to conditioned with foam...GREAT INFO...Thank YOU

So there is a vent up there with cold air coming out? And heat in the winter?

I just got a new roof and changed to a conditioned attic since I have a lot of AC ducts in the attic. Night and day difference, so glad I did it. Now it's 78 degrees in the attic (same as house temp) instead of 120F on hot summer days. I went with 3" polyiso insulation and lightweight concrete tile mounted on battens. The air gap between the tile and battens allows hot air to rise and cool the underside of the tiles -- that serves the same function as a vented attic. I was originally going to put mineral wool between the rafters in the attic as well, but because of the good performance I will probably skip that step. With modern insulating materials (polyiso) I think it's crazy to design attics the old fashioned vented way. Another benefit I didn't think about originally - closing off all the vents will prevent termites and insects from flying into the attic.

I didn't even come to KZfaq for this. But this was one of the most amazing videos I've ever watched!

I build in the suburban Chicago market. We are doing foam insulation exclusively and of course the foam is blown onto the underside of the roof sheathing and in between the rafters. It’s expensive though.

You are forgetting the reason for vented roofs is air flow to eliminate condensation. While you may get away with this in warm temperatures you still risk shingle life and rotted sheeting. This would work fine if you incorporated a dry deck roof system. I have personally repaired several roofs from the rot of an incomplete system as you are showing. It is a fantastic system if you take care of the condensation.

Every time our AC comes on we get a blast of super hot air… we are in Central Florida.

Awesome and informative video Matt. It sure gives a lot to ponder on for repairs and renovations. I've had the attic on the project back log for a while since its construction is identical to the first one in your video and a real pain the in butt to crawl around in. For both mobility being 6'1" and worries of causing damage to the truss's while going from 2x4 to 2x4. It would be nice to open up the attic but not sure on what type of re-framing techniques would be best. I did not see a video similar to my situation on your list (unless I missed it) and was wondering if you could point me in the right direction. Keep up the great work and thank you for the content!

I've seen good designs where the HVAC is in a closet in the conditioned space, ducts in lowered ceilings in hallways, and fake beams, or between floors. All of the benefits of a conditioned attic without the concerns of needing power to dehumidify that space.

I'm amazed at the condition of the way the stretch duct has been done, those are some beautiful bends, instead of the atrocious corners I see when people hang it down.

The rockwool just looks nicer.

I do HVAC for a living in Texas, I wish attics looked like that, they are the bane of my job.

Great information on this video!!

Hello Matt! Thank you for the videos! My house was built in 1997 -- I live in Dallas -- and would like to use Rockwool in-between the attic ceiling rafters like you did in the above video. My question is, did you do a vapor barrier between the Rockwool and the inside attic roof?

This is great if you have a tile or steel roof, but if you have asphalt shingles you better check your warranty because many shingle companies won’t cover damage or reduced lifespan caused by excessive heat the shingles experience if the under side is insulated instead of open to air where the heat can dissipate.

I built my house back in 2012. It's spray foam ("flash and batt") and has an unvented attic. It's great.

Well Matt conventional roof rafters have been the standard method in many parts of the country since the founding of the country. Difference is however it takes more skill to layout and cut rafters on site than it does to order engineered trusses from a factory. As for the insulation, contractors can only use what is available, and that has changed over time.

That’s great if you’re building a house with a high budget. But what about everyone else?

Hey Matt, It would be nice if you could cover a framing, insulation, and barrier package for a vaulted ceiling build with no attic. In CA, many homes are pier and beam, so ducts are under the floor instead of in the attic. Vaulting a ceiling is a common home renovation request.

Hello Matt, The name of the property that coating is exploiting to reduce heat transmission to the foam is "ablation" . An interesting fact is this same technology is used on spacecraft to protect the craft and passengers on re-entry.

Nice work guys; damn!

Would be nice to explain approximate costs of this attic construction (with that very complex air handling with vast numbers of flexible venting pipes) versus the typical loosely insulated attic. I suspect it is prohibitively expensive for most people. I also suspect that in many areas it would be difficult to find a contractor capable of this more advanced type of attic insulation.

I knew someone that did a commercial install of closed cell. I asked how do you know when there is a leak? They said they had one, it built up water until it busted like a balloon onto the floor space.

Love learning from you thank you

Which would you rather have for a roof, engineered trusses or rafters ? Engineered trusses allow you to open the area below. Rafters allow you to open the attic which you can convert to a living space or "condition" it which is what they are doing here. As for the foam I wouldn't bother, no way it's less expensive than dry wall and you can't tell if there's enough or if it's covered properly etc. You can see drywall and you can vary the thickness and you can add metal fairing channel for a little more sound proofing etc. If you have trusses and your attic is hot in summer consider adding insulation between each truss at the roof line. I think I might try that.