Insulating and Air Sealing an Attic with Spray Foam (Long Version)

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On this episode of Dr. Energy Saver's "On the Job" series, Larry Janesky, founder of Dr. Energy Saver discusses the importance of an energy efficient attic, and shows us why it should be the number one priority in terms of energy-efficient upgrades with this spray foam attic insulation project.
The typical attic is vented and not considered part of the conditioned space of the building. Attics are typically very hostile environments, as temperatures change drastically, year round, according to the seasons. In the winter time, the attic can get very cold, with freezing air getting into the space through open soffit and ridge vents. In the summer, the sun radiates heat through the roof, raising temperatures in the attic to scorching hot levels, much higher than the outside temperatures.
If the attic lacks adequate insulation and proper air sealing -- and according to the U.S. Department of Energy, a significant number of homes in America have this problem -- these dramatic temperature variations will be transferred to the living areas, either conductively through the ceiling, or through air leakages.
In homes that have HVAC ducts running through the attic, energy losses can be even greater. During the winter, heated air will lose temperature as it passes through ducts that are housed in a freezing cold attic. During the summer, the cool air running through a scorching attic will get warm before reaching the rooms that need to be cooled.
Consider that an average of 40% of your home's total energy consumption going toward heating and cooling! With such large percentages of energy consumption going toward heating and cooling you will easily understand how important it is to conserve as much energy as possible in these areas.
The typical attic insulation job involves isolating the attic from the house (conditioned space). To do so, we utilize spray foam, to air seal any gaps that may cause air from the conditioned space to leak into the attic. Spray foam is applied around gaps around light fixtures, plumbing, wires, wall partitions, and chimneys in the attic floor. After air sealing is complete, blown insulation -- fiberglass or cellulose -- is commonly used to bring attic insulation R-Values up to the U.S. D.O.E. recommended values for attic insulation for each specific region of the country.
In this particular home, however, the attic wasn't a typical attic. The multi-level ceilings stood over walls that protruded from the attic floor, making it very hard to seal and insulate. This attic also included over 100 can light fixtures, posing some difficult challenges when it came to insulation and air sealing. To make matters even worse, the HVAC ducts ran through the attic!
For special cases like this, the best approach is to include the attic into the conditioned area of the home, and establish the roof, not the ceiling, as the thermal boundary. While there are a number of different materials that can be used to transform a vented attic into a conditioned space -- including Dr. Energy Saver's Super Attic System, this particular job, spray foam became the insulation material of choice.
Spray foam expands when applied and fills gaps and voids, so the space is air sealed and insulated at the same time. With our job complete, this homeowner now has a more comfortable home and already reports big energy savings from the newly insulated attic.
Would you like to have a more comfortable home and save money on energy bills? Let Dr. Energy Saver help! Call us or visit our website to locate a Dr. Energy Saver energy specialist in your area, and for a free consultation!

[@10tenman10]

Ditch the music.

[@markrogge3098]

How did you address the existing vents? You didn't mention that on the video

[@qazwas2001]

what did the follow up door blower test show? I was looking forward to seeing that in the video.

[@ericviele4379]

Same here!

[@notransfat1]

Great video. The background music very distracting and annoying. Can you edit the video to remove the head-banging noise and repost?

[@callahancovington4278]

What kind of quality control measures do you use to make sure your dealers are delivering consistent, high quality work as seen in your videos?

[@PanamaSticks]

What did you do with the ridge and soffit vents on that home?

[@enkrypt3d]

this is what I'm trying to figure out... it looks like they sprayed right over it?

[@travism9197]

I'm assuming they went with a hot roof. Otherwise they would of needed to vent chute the whole roof up to the ridge

[@robertdyfoon3976]

Couldn't watch anymore annoying music

[@belews]

John what did you do about venting? Is this even needed now??

[@carolinawren3594]

A couple of key elements Larry forgot to mention. 1. The difference between closed and open cell foam insulation, both in performance and cost. {Open cell insulation is in the same category as other insulation products, fiberglass, mineral wool batt etc) Closed cell foam is also a vapor barrier, contributes to the structural rigidity of the building, can be applied directly to the underside of roof sheathing, and costs twice or more what open cell foam does. R806 of the residential code requires continuous ventilation between the underside of roof sheathing and insulation. Many products are available to provide that but with anything but closed cell foam insulation that plus soffit and ridge vents are required. 2. The amount of confusion about this subject in the 'stick built' industry is ridiculous. Another place where the building code is 50-100 years behind the times. 'Authorities' abound who argue that insulating an attic floor and making the attic space an 'outdoor' space is an ideal solution. And then there's the crawl space.

[@appleguy6708]

I would like to see those proofs of energy savings

[@yoyoma99]

Without venting the roof, I believe ice damming is still a risk. The decking insulation will reduce the heat transfer to the shingle in the winter, but shingles will still be warmer than the outside. Therefore it can still melt the water when it's 30°F outside, and then refreeze in the gutter. Thus an ice dam will form. I believe this method of insulation is okay in the south where ice dams are not a big problem.m

[@HarmonsHarbor]

Correct, ice dams will occur, but they won’t be nearly as severe as when you have heat escaping through the sheathing 24/7. Even though ice dams may occur, that’s why it’s critical to use ice and water shield on the sheathing. Some say to put it from the overhang edge and 3 feet past the living space and in any valleys. I say put it on the whole roof for added protection.

[@larryjanesky8185]

Soffit vents are sealed obviously. Blower door numbers were reduced by 3000 cfm and fuel bills reduced by 50% - and this is after many other improvements were made the year before - we still got 50% reduction in fuel from that lower level of usage.

[@jollyjoshhalo]

If you sealed the attic, won't the humidity just stay in the attic? Also, I saw you sealed the ridge vent, do you also close the soffits?

[@renegarcia1798]

You put your exhaust fans out of the roof that's how you eliminate humidity

[@lovera3878]

Hello Sealing the attic sealing seems fine. But having had two recent leaks in my roof I am concerned about the water staying trapped in the plywood and rotting it rather than going through to the drywall and thus warn me about the leak. Is that fear justified. My attic is blistering hot in the Summer and I am looking for a solution. Radiant barrier being one of the options.

[@babartahir9004]

carlos lovera Good point, was thing the same👍

[@DK-wl4ne]

Very good point. If you use open-cell foam it will allow water to get through as it isn't a moisture barrier. I recommend this because if you have a leak, you'll get your normal, "why do I have stains on my drywall" signal, and will be able to address as needed. Using closed cell, or a moisture / vapor barrier could lead to moisture being trapped under the shingles and cause a lot of rot - eventually compromising the framing. Also note - once you do this, your roof will be a real pain in the butt to replace in the future, as that spray foam will adhere to the ply. If you ever need to replace the ply, pulling it up will leave pockets that will sweat and cause damage, even with an intact roof above. You will need to fully remove all foam under any plywood that needs to be replaced, and reseal it afterward. But, when you're talking about cost saving, over the course of 20 years, you'll probably save 5x more on energy costs compared to the extra labor you'll have to pay for a roof replacement, and you'll also have a much more comfortable home.

[@robertayesho8909]

Great information, but ditch the music.

[@jnagle351]

Did you eliminate the ridge and soffit vents?

[@piercecushenbery5876]

gas refill men hate dr energy saver for this one simple trick

[@rasheemsanford9348]

Overall efficiency aside, with converting the attic from vented to conditioned space, does CC affect the shingles’ ability to breathe?

[@mattd6891]

Question re: less costly way to help determine locations and extent of air leakage into attic. Couldn't you just maximize the difference between the unconditioned attic and the conditioned house (eg-max heat in Winter or max A/C in Summer) and do some thermal imaging around the attic to see how many hot spots you had and then deal with those??

[@ericvanzeyl4483]

My question for you Dr Energy. Now that they have the spray foam, did they put in something like an EVR to bring in fresh air and take out the moisture? if not, they will have a lot of mold growth? I am building right now, and plan on doing an EVR after I get my whole house like a closed envelope.

[@RugbyNick6]

ERV

[@ericvanzeyl4483]

@@RugbyNick6 Thanks, I Guess I had a typo 🙂

[@enkrypt3d]

one thing you should mention is if you have a gas furnace in these attics, you have to deal with the combustion intake! otherwise it will cause problems..

[@johnbonds5084]

What did you do about the vents from the soffit to the ridge vent? Is it not necessary to add baffles to vent the roof surface so the heat from summer sun doesn't build up and cause the shingle life to be shortened?

[@MrTonyFox]

I have a situation where they applied about 3" of closed cell foam across the bottom of the rafters. I have no way of knowing if I have a roof leak. If I do it could run down into the exterior walls. Is this application against code???

[@danielanderson4709]

Tony Fox wouldn’t you be able to tell if you have broken shingles on the roof?

[@MrTonyFox]

​@@danielanderson4709 Hi Daniel, I've been a General Contractor since 1985. Any roof leaks I've run in to were found from the bottom, thus trying to locate it from the top. The only way I would know that there is a rook leak on top is if I saw some lose flashing or an obvious hole. I've had two of my Roofers also look at it and they said they have never looked for roof looks from above and neither could ever issue a roof inspection report unless they could see the underside. Having said that, if they would have sprayed the foam between the rafters, at least we could see water damage and/or stains on the rafters indicating a problem. Not being able to get a written roof inspection is a Major problem, ie;, re-sell. I also had another Foam contractor tell me he has never seen it done that way and I couldn't get a termite inspection since they couldn't see the rafters and sheathing. This is a major problem in my opinion!!!

[@hickorydragon8114]

But you don't have as much thermal bridging from the rafters.

[@billygraham5589]

I just have one concern about foaming the rafters and spaces in-between the rafters -- what if the roof gets a leak? How would you find out about it??? You would not until the roofing plywood was completely rotted. Not to be a party pooper here, but, in fact, there is no "ideal solution" to insulating a house.

[@AndrewMiguelez]

Correct. It is common for the roof to be covered in snow and ice shield instead of just tar paper when using this solution. Added security against sheathing rot.

[@michaelgelewski4877]

You didnt give the results of the blower door after foam install. Why?

[@CharlieWayneAdventures]

Disappointed u didn't show how u sealed between the top plates and roof deck around the outside walls. Also as others said, what was your CFM After your work?

[@jimfranks]

With this video being 9 years old, is the "solution" provided still the recommended one? Was the ridge vent/soffit ventilation existing in the house closed off, and if not how does that work post spray foam? Thanks.

[@PamSantos-rb5re]

The music behind your talking is quite annoying. I can’t listen anymore!

[@CraigBushon]

I didn't see you mention what you did with the soffit vents while sealing the attic.

[@Sunset1997]

What happens to moisture that enters the attick if there's no venting?

[@DavidSanchez-zq8fp]

If the attic is conditioned space the moisture is being controlled the same way it is in the rest of the house by the HVAC system. It wasn't mentioned in the video but in order to do this you'll have to put HVAC vents in the attic.

[@jssj2851]

I appreciate the video, but there is is one aspect that was not addressed, and that is how the soffit and ridge vents were delt with. If you could please.

[@ratandmonkey2982]

yeah, I heard of winter, spring, fall and summer, ...

[@joestallings6993]

I wanted to say the same thing about the background music. Very annoying.

[@jackjones3657]

So he used closed cell foam followed by a spray vapor/thermal barrier. I'm wondering what they did about the ridge vent(s)?

[@mrfixit7047]

if your attic is like a cooling fin to the shingle, then why would you plug up the cooling fin. How is the air going to go up the back side of the shingle to keep it cool and not shorten its life. They will just have to replace the shingle more often. The 50 year shingle will fail in 10 years just because it was cooked daily. Also some the air flow stops you from hitting the dew point with any 20 plus degree changes in temp to stop condensation

[@MulloyDIY]

Hi Dr. Energy Saver - Do I need to have insulated ducts for the bathroom fans if my attic is a conditioned space?

[@analyst8258]

What happens when the roof leaks withis insulation. So, will this insulation affect attic ventilation anyway?

[@sagex93]

it seen good but what was the price ? 15,000? 20,000? more ?

[@enkrypt3d]

if only he answered the 3500 questions on his youtube channel! Hellooooooo?

[@kcjcwarner]

When using spray foam to insulate an attic that has storage trusses should the gable walls also be insulated?

[@easttxtycoon]

This was Larry's house, too bad it burnt down.

[@rockslide4802]

Incredibly informative and well done video. But please lose the music! It adds nothing and detracts from what you are teaching us.

[@mepipeline]

Do ou have a branch office in Sacrameno, Norhern California..?

[@travisdunn8276]

Would you want to spend the time to air seal all the air leaks into the attic so that the warm home air stays in the house?

[@billygraham5589]

And do wear your dust mask going into an attic with insulation -- check out this vid at about 12:45 to 12:50. (Watch the fiberglass particles/fibers floating all about in the air.)

[@korona3103]

Ah he does, check the pics of him doing the regular work, these guys are good for PPE. Can't really talk through a mask though!

[@GlueFactoryBJJ]

Great video! Ditto to @qazwas2001 comment below! Larry mentioned "before" the blower door test was moving 11,500 CFM, but didn't mention "after" value. Do you have those numbers? Also, what % did the homeowner reduce his utilities (gas/electric) by? Even a worst case (low estimate) scenario would be helpful. Finally, what was the approximate $/SF cost of this job? Was there anything else done that might affect the cost other than what was mentioned in the video? Thanks for your help!

[@ldtenenoff]

should you air duct ur attic as well as blowin insulation or is it better to insulate rafters

[@bolu3846]

shingle life will be greatly shorten because they will be really hot in summer

[@DavidSanchez-zq8fp]

Not true. Although it may seem logical that the decking temperature would be increased the evidence doesn't support it. You can find a number of tests on youtube showing no significant increase in decking temperature after the attic was sealed.

[@corygerling1876]

If I wanted to spray foam my attic and seal it up would the existing cellulose insulation on the celings need to be removed?

[@doctordev97]

Nope, keep it. even if you seal your attic, you still want the energy you use to heat your home to stay in the living space of your home. having insulation between the attic and the ceiling will assist in that.

[@joestallings6993]

You give compelling reasons to insulate the roof. I can imagine things stored in a more room temperature attic would fare better as well. But, what happens when a roof develops a leak? The open-cell foam would act like a huge sponge potentially spreading damage over a large area. And since you're sealing the back side, the water would run down the wall below?..

[@TripSmith]

Wow, good point...

[@rachelvirienna]

Joe Stallings My Dr Energy guy said that open cell was better for this reason. With open cell it leaks through the insulation and you can see it leaking, vs closed cell where it would be hidden in the attic

[@kansasgardener5844]

I wouldn't use spray foam in my home. For one if your roof starts leaking you won't know it. Second, all the air leaking into the attic from that room is still going to leak into the attic and out the ridge vents. So, I'm not sure what this guy is talking about. Your still loosing the warm air from inside the house. A better option is blown in insulation in the attic.

[@alejandrogazu6705]

That's why you SEAL the attic.

[@christopherathomas]

Hey John, Is there any problem with using spray foam under an old tin roof (metal partially exposed? I was thinking that condensation would be a concern. I'm waffling between baffles + foiled board foam or spray foam. Additionally, I only have two gable vents, without soffit or ridge vents. I have a really old home that definitely needs some work. Thanks!

[@roywells5790]

Christopher Thomas foam the exterior of the roof you get the insulation and a seamless leak proof system in one also adds structural integrity 50lbs compression per sq. In.

[@Bajaheat]

Wouldn't the attic be a lot warmer in the winter and make the bottom floor cold in the winter from all the heat rising?