Insulating very irregular wall cavities
Greetings all, we are at the insulation stage of our 1st floor kitchen remodel. This part of the house has been remodeled so many other times that there is nothing resembling regular 16″ OC stud spacing. I am wondering what is the best route for getting this wall insulated. I KNOW there is no way that fiberglass batting will be very efficient. Every single piece would have to be cut on 4 sides to get a good fit (too much chance for error).
The FHB article on damp fill cellulose seems very intriguing. What is the cost comparison between that and sprayed foam?
I attached a picture of the worst wall with arrows pointing to a number of the trouble spots.
The other factor is that nothing in my house is very big. This wall is 10′ tall, and 12′ wide. The other two walls maybe add up to another 300 sq.ft. less 50 or so for doors and windows. Part of me thinks that I could do it with $20 of expanding foam from a can. (Kidding of course).
Replies
See if you can get a spray foam contractor to come out and give an estimate. See attatchments. You might also consider adding a layer of foam board to the studs before you drywall to add an extra measure of insul and to create a thermal break with your wall studs. Just my 2c.
Unconvinced regarding the cost/benefit analysis for commercial spray foam. There are certainly special circumstances when it would pay, but your case does not look so complicated.
Nothing wrong with your can foam idea.
For some of the tricky smaller cavities, you can use pieces of rigid foam blocks to take up some of the volume, then apply can foam around them. Rigid is much cheaper, plus can foam tends to fall out if the void is too big.
Spray cells is good, but it can be difficult to locate an applicator. Also, this appears to be a small job, so a good price is unlikely.
You could blow cells in the larger cavities. Blown cells pack around anything. Plenty of posts here about netting material to hold the cells in, or you can leave a gap in the wallboard to blow into.
Cutting out ridgid foam and filling in around the edges sounds brilliant! Any suggestions on the best way to cut rigid foam? I have found it frustrating in the past.
I use a 'break off' knife to cut foam. (http://www.olfa.com/)
Nice long sharp blade when extended. Foam does not tend to snap off the blade segments, since it is soft. Several passes with the blade at a steep angle produces the best cuts on thicker stock. Leave a 1/4 inch gap all around to can foam it in place. Cuts do not have to be precise with this method.
The 'right' foam cutting tools are heat knives, but they are expensive.
I think Corey has the right idea. I'd suggest using as thick a foam as you can get in there.
You can also cut foam board with skillsaw, just do it outside and wear a mask.
If you use thicker foam (3 or 4") it's tough to cut it without a saw, IMO.
Hate to say it, but HD has by far the best price on regular expanding Great Stuff. Here it's $4.49 for a 16 oz can. Just bought some.Something is what it does.
Haven't tried it on rigid foam, but your DW's electric knife works great on 4-6" soft foam in upholstery.
Most any sharp serrated knife should work well--without all the mess of an electric knife/saw.
Thon
In a bind for a saw to cut 2" foam boards, a carptenter's hand saw did the trick for me with about as little mess as I could have expected. Razor blades dull way too quickly to get clean cuts and I did not have an electric knife (serrated or heated).
With the hand saw you can trim accurately with little mess and everyone has one!
Norm
Table saw works well, hand saw too. just cut 1" under size and then foam 1/2" around all sides.
Been putting in 2" all week end..in odd rafter bays..using a cordless circ saw for the first cut then grab a butcher knife for the last 1/4 inch. works great. a Pull saw to sculpt it to my log rafters..
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