oops!

[dug]

I have known of my mistake for some time but now I have to deal with it before I move on.

When building my walls I framed the corners like this-



and painted myself in a corner, so to speak, as far as insulating them.

I was thinking about drilling small holes every foot or so and filling them with canned foam sealant. Seems like it would require quite a few cans but would probably do the job. Thought also of getting loose fill insulation and somehow filling it from a hole near the top but I have no experience with the stuff. Would I have to rent a machine? How big of hole would I need to drill?

Any better options?

[suburbancowboy]

I would go with your can idea.  Give the foam time to expand as you work your way up.  To much and it will come out the holes.

[JRR]

If you did nothing, I would suspect the heat loss/gain would be less than a door jamb of the same dimensions.

[rwanders]

The foam will work----just takes a little patience.  Seems to me the critical spot is the vertical seams on an outside corner since that  is where you may get some air leaks so be sure and catch them good. Those spray cans will fill a pretty good space. It may only require 1 or 2 cans per 8' corner. I would drill small holes along both faces so ensure good coverage of both sides and the seams. a very small squirt will seal a hole up after you are through with it.

ps; Might be a picture angle thing but looks like you may have kind of a small area for nailing along one face---if so, putting SR against that short side first will help with the other wall

[dug]

If you did nothing, I would suspect the heat loss/gain would be less than a door jamb of the same dimensions.

Ha ha!    I didn't think of it that way but of course you are right. I keep getting a picture in my mind of an infra red shot of the house in winter with the corners glowing red and can't deal with it though. I'll try to fix it using foam.

Thanks rwanders for the tips. You are right about the corners, not the best design in many ways. 

[Bill Houghton]

Dug, are you wiring this structure?  You may want to install your wiring before you fill the outside corners with foam. 

[Squirl]

In some of the books I read, people would cut a notch in the top and fill it with cellulose.  It looks like you framed it in 2x6 and they are closer than 2ft O/C at the corner.  A 2" notch in each should not affect it structurally and you will have a 4" hole to fill in the corner.  You can always put a block back in the notch you cut out, and it should be find.

[Alan Gage]

No experience here but I'd go with cellulose. I'd think you'd need a lot of holes to do it with foam. Otherwise I'd worry about it expanding before it dropped all the way to the bottom, causing lots of gaps. With cellulose you could could probably just do a 2" hole in the top and blow it in.

Our building center lets you use a blower if you buy the cellulose from them. Otherwise rentals are pretty cheap. Easy to use.

Cellulose is cheap, effective, and about as environmentally friendly as insulation can get. Foam will never biodegrade in a landfill.

Alan

[dug]

dug, are you wiring this structure?  You may want to install your wiring before you fill the outside corners with foam.

Wiring is in already.

Thanks squirl and Jeff. I had some of the cans of foam already so I tried it in one of the corners. I don't recommend it. I emptied 6 cans and got maybe 7 of the 10 ft. filled, still voids here and there as well. Its really difficult to know if you are putting too much, not enough, or where it is actually going.

I am going to try the cellulose on the rest of them but I wonder if I could just pour it in and help it settle using a palm sander or something to vibrate it?  I'd hate to rent a machine for such a small job.

[MountainDon]

I somehow missed this thread till now....


I'm surprised at the amount of foam you used and that the cavity was not filled. I had a similar situation and used great stuff to fill the corner. I did use the version that is made for big gaps. I don't remember how many cans I used but I know it was more like two or three. Wetting the wood before spraying in the foam helps the expansion; especially helpful in dry climates. (FWIW, when using polyurethane glues in a dry climate it also helps to wet the wood first or to spray a fine mist of water on one side after the glue has been applied. These products can usually absorb sufficient moisture from the air, but when the humidity is 20% or less, extra moisture helps)  I drilled holes, maybe 2 inch dia., using a rotary hole saw, through the inside corner about every 16 inches of height and inserted the application nozzle through those. Then knocked off the over exapnsion before it was completely solid.


Don't bother with a machine. The ones the blue and orange box stores have are only suitable for attic installations; not made for blowing into wall cavities. Drilling large holes with a hole saw would give room enough to hand insert fiberglass or cellulose.

[dug]

The cans were just the 12 oz. ones (on sale) triple expanding foam.

Don I believe you are right about the dry air here. I was sealing around some windows today and watched as the foam went on and then it shrank and started to liquify. It was 50% expanding foam and some of it actually ended up about 50% less volume than when it started!

[rwanders]

    Think that is why it was "on sale"?  I had similar experience as Mtn Don. Controlling overly enthusiastic expansion was the problem I had (used "Great Stuff" brand)