Insulation Man

So you know how I said we were going to spray foam our attic? Ignore everything I said cause we did a total 180. πŸ˜‰ So here is the scoop. Last Wednesday, we were supposed to have spray foam installed (notice, past tense). On Tuesday, I made the mistake of doing some extra research on the stuff that scared the be-jesus out of me. Namely spray foam can kill you. Ok, I kid, I kid.

The biggest red flags for me were that this stuff has tons of off-gassing that is super dangerous if you’re exposed to levels that are too high (this thread, in particular fa-reaked me out). Some people have reported neurological issues and anyone exposed to too high a level can develop a sensitivity where any type of foam product can set them into an asthma attack. Foam that might be in say, your pillow. Yeah, no good. The installer tried to calm all our fears, but at the end of the day, I just couldn’t wrap my head around the potential issues down the line that might result from unsafe levels of the gas. Since this room will be our bedroom, it seemed important that we were not gassing our selves to sleep each night.

So we decided to develop our own strategy for sealing off the space. After lots (and lots!) of discussion, we decided on the following tactic.

How to Insulate Conditioned Attic

First, a quick disclaimer. Jay and I did TONS of research on the best way to insulate our conditioned attic, and one tried and true theme that we found was that there is really no consensus on how to best insulate. Well, I mean everyone agrees that higher r-value = more comfort and lower energy bills, but your method to getting there is the debatable point. It was super frustrating and eventually we just started beating to our own drum and came up with our own solution (above).

Since we were not proceeding with spray foam, which would have created a hot roof where no venting is required, we decided to use a 1″ piece of foam to create our baffle to allow air flow. That foam did two things, first it created air tight conditions for the fiberglass, and second it had r-value, vs. the plastic sheathing that is typically used. Rock.

How to use foam board to insulate attic

To create the 1″ of air flow required, we simply cut some small pieces of foam, and glued them directly onto the roof deck, like the photo above. Then, we came through with the foam and attached it to the spacers. Now getting the foam into the cavity, that was one hairy beast. We wanted the fit to be tight, so we had to really work at getting each piece in. By we, I mean Jay, since the sound of styrofoam is a painful torture device for me – like nails on a chalk board, man – I would fly out of that room screaming every time he popped one of these babies in. I cringe just thinking about it.

After we got each piece of foam in, we came back through and used HVAC tape (sticky, sticky stuff) to seal each seam between the roof deck and the foam board. Time consuming, tiring, but effective.

Using Foam Board to Insulate Attic

Just installing the foam took us 2 days. 2 FULL days, and that didn’t include a few sections over the stair well that we were unable to reach and will have to come back to later. Now we felt good about installing this initial barrier since it effectively made the space pretty stinking air tight, and with insulation air leakage is enemy #1. But in all honesty, this was extremely tiring. Totally worth it, but every night we would practically crawl into bed.

Another fun detail – since we were venting the roof, we had to install holes for air circulation on the outer edge of the roof. Our roof had previously been unvented (that’s bad), so we had to come through and pre-cut holes for a soffit vent to be added post insulation install. I think this was Jay’s favorite part (not). Super dirty and time consuming to cut each hole. We had to go outside for each one to test with a light to make sure all systems were go, and verify that a sufficient hole was cut.

How to install soffit vents

After we had all the foam up, we came back through with our fiber-glass to fill the rest of the cavity. This combination let us achieve R-18 in all the walls as our base layer. Spray foam would have gotten us R-21, so we were pretty close to the same effective R-value with just these two layers.

How to Insulate Attic Walls

Since I had read all the perils on fiber-glass where many industry experts essentially noted that many people don’t install the product right, thus vastly reducing the R-value on the product, we were super diligent to make sure this part of the install went as close to perfect as possible. The things we were trying to avoid with the fiber-glass, were.

  1. Bunching, scrunching etc.
  2. Leaving any gaps
  3. Not using canned foam around light fixture, holes, etc.

Basically, it’s really easy to be sloppy with fiber-glass, but taking the extra time to do it right will ensure a much better long-run effectiveness of the product. We tried to be super persnickety on this step, and hopefully it pays off in the long term. How to Insulate Attic

When I was sleuthing into the pros and cons of fiber-glass, I also stumbled across this product, which essentially creates a thermal radiation barrier. Even though it’s super thin, this layer has an R-value of 5-16, depending on the installation technique. Since neither of the home improvement stores had this product in stock, we had to order it online, so we are still waiting on this in order to put in our final layer. When we do get it, we will essentially wrap the entire room in this stuff. Space age. Robot room. Glass castle. It’s going d-o-w-n.

Now, before we got the wrap installed in the room, we took this as an opportunity to spec out the joint and check for any air leaks. Let me introduce you to my little friend. Mr. Flir.

FLIR Camera

This little guy tells you everything you need to know. All the secrets of your room. The spots where old man winter comes to sneak in. Now, if you don’t have a husband that happens to have a flir camera at work to give you infared images of where all your heat is sneaking out of yo house, the best way to get all of this information is to get an energy audit. Around our place, that sets you back around $100, but it also gives you lots of important deets on your house, like where all your air is leaking out. When you’re paying to heat your house, you generally want to avoid having vast quantities of it sneak out of cracks and crevices.

Since we’ve already had an energy audit done on our house, we skipped it the second time around and just used the camera as a way to fine tune the install and avoid any air leaks. It’s always best to do this along with a blower door test, since that essentially exaggerates any holes you might have by literally blowing all your air out of your house, but we had a pretty good baseline understanding of our problem areas from the first time around, so we nixed it.

FLIR Camera

Now, one majorΒ advantage of skipping the spray foam and going the DIY route, was that it saved us many, many dollars. Like $2,000. That is a whole lot of cash-ola. Our final quote, for 3″ of spray foam in the roof (R-21) and 2″ in the walls (R-14) was $3,400. With our more conventional route, we will get R-23 in the roof (R-53 in the top section, above the ceiling) and R-18 in the walls. The spray foam would have, most likely, been a bit more air tight then our DIY route, but I think we did a pretty darn good job of sealing this guy off. After scanning over the room with the camera, we used a can of great stuff spray foam to seal off any leaky areas. Like this.

How to seal air leaks in insulation

At $7 a can, we were able to just buy a few of these, and use them where needed, vs. spray foaming the entire roof cavity. Money well spent.

Great Stuff Spray Foam Insulation

After we bought the 1″ foam board, the fiberglass insulation and the foil radiant barrier, we were at under $1,200 for all our supplies. Here is the break down for you:

  1. 800 sq. feet of foam board: $375
  2. 1,000 sq. feet of fiberglass bats: $400
  3. 3 cans of spray foam: $15
  4. 3 rolls of HVAC Tape: $30
  5. Thermal foil barrier: $340

Now that doesn’t include all the blood (Jay got the worst splinter of his life, I think he thought he was going to die), sweat (it gets hot up there) and tears (I may have shed 1, or 2.) that went into this beast. I’d add an extra $100 for a nice dinner, kinda help to ease the pain a bit. πŸ˜‰ But even including the nice dinner, we are a cool $2,000 below what we were quoted for spray foam. And that was the cheapest quote. As George Bailey would say – hot dog. Hot diggety dog.

As for Jay, I think he is exceedingly happy to not be sporting this guy anymore. Cheers, dear husband. May you always be warm and toasty in your new, insulated attic.

How to Safely Install FIberglass

If you’re looking to do a similar project, here are the items you’ll need:

19 thoughts on “Insulation Man

    1. It’s pretty rare – but we didn’t want to take the off chance of being one of the family’s effected by a bad install job. I’m a total sucker for attic spaces, too! πŸ™‚ Thanks for swinging by, Naomi!

  1. Hi Mary! Have you guys thought about air exchange in your home? Having everything air tight is what you want for energy savings, etc., but at the same time, if the air in your home isn’t moving, it can lead to increased levels of pollutants. Here’s some info on that from the EPA:

    You know, the mom in me just can’t help throwing this advice at you two, who I love dearly!!

    1. Hey Deb! Yes!! That came up a lot when we were meeting with different installers. Jay has been doing lots of research on some attic fans that can be installed to exchange the air efficiently. So many things to think about – it’s been a learning experience for sure! πŸ™‚

  2. Looks like you guys put a lot of thought into this installation. Looks like a ton of work! I’m enjoying reading your blog. πŸ™‚

  3. Radiant Barrier is a great idea, we have been putting it in residential homes for over 10 years. There a lot of factual articles on it, and it will reduce your energy bills significantly. You can go to our website and research for your self, I love your idea though.

  4. Hi,
    Thanks for posting this. I too, was planning on spray foam and then found some scary stories. I wanted to ask about the peak of the roof. It looks like you did not add roof vents at the peak. Are you relying on the air flow from the soffit, up the roof and then down to the opposite soffit vent? If so, do you have the information detailing this aspect of the job. I have the same situation regarding the venting. This would make the job affordable and diy. Pretty fantastic!
    Thanks for any info you can provide.

    1. We actually had roof vents already installed but had to add our own soffit vents πŸ™‚ It was much less expensive than spray foam! I think in hindsight I worry a lot less about it (seems statistically very rare to have adverse impacts), but this route was definitely cheaper πŸ™‚

  5. Hi,
    Good article, thanks for sharing your information on insulating your attic. I like the idea of the one inch foam spacers for venting before installing the rigid foam.

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