Foam on Rim Joists


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Old 11-01-17, 09:00 AM
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Foam on Rim Joists

What do I use to properly foam my rim joists? I have some hard to reach spots.

I have seen the big cans in the store, which thread into a big trigger applicator. Is this what I need? If so which type of foam can should I use? --Because I see they are marked for different applications.
Thanks!
 
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Old 11-01-17, 03:37 PM
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Hi Gen,
The foam guns are nice for doing a lot of work day after day, but they are a pain to clean up and keep from getting clogged. Mine has a special cleaning fluid that is as expensive and a can of foam. IMO, use the cans where you can toss them when done. As for reaching tough spots I picked up some plastic tubing that fits over their straws. Just a few extra inches helps a lot but don't go to extremes and use a good tape to secure the extra tube.

As for which foam, they have regular expansion, large gap, and low expansion for doors and windows.

I have one of the guns, but prefer just cans unless I need to reach a difficult place as I have longer tips and extra tubes for it.

Another option if the can just can't get in there is rope caulking, it is like putty and you push it into place with those universal tools, fingers.

Best,
Bud
 
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Old 11-05-17, 07:51 AM
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Thanks...can I use any can foam type? The rim space is like 14 x 8 inch.
 
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Old 11-05-17, 01:34 PM
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Great Stuff is probably the most popular and comes in three different expansion rates, normal, large gaps, and minimal expansion for doors and windows. In the normal (maybe the others as well) I saw some slightly smaller cans which for me would be useful when I want to just foam a small spot and the can will go bad before I need it again (retired).

If you are doing a long section of rim, not just one space, then find some rigid insulation and cut it smaller than needed using the can foam to seal the perimeter with some behind the rigid as adhesive. Can foam (and the gun) deliver the foam in a smallish bead, not a spray that covers a larger area. They do make kits that will spray but takes a higher skill level and I have never tried. Also expensive. The cut and cobble approach with rigid foam and can foam is the most affordable and does a good job.

Bud
 
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Old 11-05-17, 06:16 PM
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Thanks very much. Most rim spots were done by the foam guys a few years ago. However recently I tore out the remaining walls to expose the rest of the rims, and I noticed 2 or 3 were partly foamed over the patches of paper faced insulation that were in there. See pic.

Is this a problem? Should I dig this stuff out?

http://1105172049 (1).jpg
 
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Old 11-05-17, 06:52 PM
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I think I need help posting pics.....
 
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Old 11-05-17, 07:12 PM
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Old 11-05-17, 09:03 PM
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Hey Furd Can't click on this...
 
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Old 11-06-17, 07:05 AM
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Are any of the Great Stuff-like disposable types a closed-cell foam? I just found out the original version is open-cell and absorbs water like a sponge.
 
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Old 11-06-17, 06:14 PM
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How to insert pictures.

I guess I can't add a cllickable link. Go to this posting for a clickable link. Post #6) T Joint Above Check Valve Drains Back Into Sump Well
 
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Old 11-06-17, 07:52 PM
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OK trying again

 
 

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