DIY Home Insulation Kits
November 8, 2010 12:07 PM   Subscribe

Hi All, I need some help and recommendations on the best method to insulate one's house envelope + attic. I'm somewhat handy, but I don't want to get in over my head with skill-level or cost. I'm thinking of the DIY spray foam insulation, any recommendations? Please see detailed explanation. Thanks

I just had an energy audit, the 1st thing they recommended (and I agree) is to insulate the envelope of my house, as well as the attic.

They recommend getting a pro to spray foam insulation, which can cost $5k to $10k - I just can't afford it.

I've read about some DIY spray foam insulation kits like, but I'm hesitant since I don't know anyone who has used them, I don't know how difficult it is, or if theres a better way?

A little info on my house:
I have a 1945 colonial with plaster walls; what little insulation there is, isn't that good, outside of the house is clapboard.

I'm fairly handy, but also a new home-owner. Any help is really appreciated.
posted by absolutshrk to Home & Garden (5 answers total) 7 users marked this as a favorite
My co-worker used a spray foam system that I think he rented from the hardware store to insulate his attic. It sounded tiring, but not difficult, and certainly within the realm of doable for the reasonably handy. That said, because it was an attic he didn't have to deal with punching holes in plaster.

That was a couple of years ago, and he did see a huge improvement in heating costs, too.
posted by ldthomps at 12:26 PM on November 8, 2010

We did blow-in cellulose insulation (the fluffy cottony fuzz) in the upstairs of our 1915 2-story right after we bought it. The situation was that we were laying drywall over the dilapidated plaster walls in all the upstairs bedrooms, so cutting holes and blowing in insulation before we covered the plaster was no big deal.

If we weren't already doing repairs, patching the holes would have been a pain. One thing we had to do was to be sure that there was something in the attic blocking the fuzz from coming up like Vesuvius. (this was 2nd floor, and in our type of 1915 construction, the subfloor goes all the way to the walls, so nothing fell from 2nd to 1st floor) In general, there were wads of paper shoved in there (from when a previous owner was blowing cellulose in the attic?) but we could only get to the stud cavities along the ends of the house, I didn't army-crawl down the joists to where the roof slope meets the attic floor, to investigate those cavities, but they didn't overflow, so they must've been stopped up. In theory, depending on the attic, you could blow the insulation in from above, but part of the reason the blower works is because there's an entrance hole and an exit hole, not just a pit to throw fuzz down - I'm not sure how to get the air flow and pressure right.

Cost for 5 bales of insulation (2 walls each of 3 12x12 rooms, plus scattering the remains around the attic) $20/bale, rental for the blower $100 or so (Lowe's had a $250 deposit that we got back). 2-person job, in one day (5hrs?) - one with the blower and the bales in the driveway and one with the hose (through the window) shoving the tip into the wall holes. 3rd person ran interference, carried messages when shouting didn't work, and called a halt when paper came loose and Vesuvius did indeed erupt in the attic. In general it was pretty easy work - could tell by the sound of the blower when a cavity filled up, and although my husband was comically covered in fuzz, we just ran the shop vac over the whole rooms and it all cleaned right up. Might have been a different story if the room had been finished and furnished and lived-in, though.

The advantage of the contractors is the reduced disruption to your life - you can spend all your energy on protecting your furniture, repainting the walls, etc. If you do it yourself, you'll need to set aside a whole week: furniture moving, stud-finding, hole-cutting, tarping your stuff - rent the thing for a day and insulate - then cleanup, hole-patching, more cleanup, painting, furniture moving, etc.

In any case, good luck, and remember - for insulation, anything is better than nothing!
posted by aimedwander at 2:50 PM on November 8, 2010 [1 favorite]

Best answer: DIY spray foam is not really cheaper, unless you are doing only a small area. We recently paid $14.40 (Canadian dollars) per installed cubic foot of BASF eco spray foam. offers $13.69 per cubic foot.

There are two issues to consider: 1) insulation and 2) air sealing. Spray foam is good for both because it has a high R-value (it insulates better per inch) and it is an air/vapour barrier at sufficient thickness (it stops your warm air from leaking out of the house). If you don't have good air-tightness already, then you'll need to improve that either with spray foam, taped foam boards, or plastic vapour barrier. Once you start comparing the costs of installing a vapour barrier otherwise, you may find that spray foam is fairly affordable. Your other option is blown in cellulose or other material, but this may not be great for you if you need air sealing or you don't have very thick walls (blown in cellulose is only about 60% as good insulation).
posted by ssg at 5:11 PM on November 8, 2010 [1 favorite]


When you blew in the insulation, what size holes did you need in your walls (interior, right), and where were they located?
posted by thefool at 6:42 PM on November 8, 2010

We found and marked the studs, then for each cavity, drilled a hole using a 2" hole-saw drill bit, about 8" from the ceiling and about 8" from the floor. This included 2 holes per cavity both above and below the windows. (that adds to a lot of holes: 12' wall has ~9 cavities, 2 or 3 of which are cut by the window, so that's about 24 holes?)
The blower came with a super-long corrugated black hose (basically identical to a shop-vac hose) and a blower tip, basically a long cone tapering from the 3-4" hose diameter down to a ~1.5" hole at the tip. The holes were cut basically just big enough to insert the blower tip a bit into the wall.
posted by aimedwander at 10:34 AM on November 10, 2010

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