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-   -   expanding foam vs cutting sheets of rigid foam for rim joists (http://www.diychatroom.com/f19/expanding-foam-vs-cutting-sheets-rigid-foam-rim-joists-86999/)

Red Squirrel 11-17-2010 07:03 PM

expanding foam vs cutting sheets of rigid foam for rim joists
 
I want to insulate my rim joists, I'm debating on doing it myself (lot of work, but cheaper) using rigid foam, or hireing it out to an expanding foam company.

Money/labor aside which one is more effective?

DangerMouse 11-17-2010 07:20 PM

Why not DIY with spray foam?

DM

concretemasonry 11-17-2010 07:56 PM

I cut my 2" extruded polystyrene to roughly fit between the joists. Then I used the expanding foam to seal any cracks and then quickly pushed in the the pre-cut foam and used the foam as an adhesive.You have to be careful not to get too much foam as a sealer/adhesive because of the expansion.

This was just a short wall and I did not have place to use the majority of the second can. A good way to use up scraps of foam if you have them.

Dick

Red Squirrel 11-17-2010 08:07 PM

Quote:

Originally Posted by DangerMouse (Post 536052)
Why not DIY with spray foam?

DM

I've thought of it, but the equipment is not cheap. If I was a business wanting to do this for others I could see value, but for a one time thing, not really worth the investment. I suppose I could buy a bunch of cans of "Great stuff" but I'd probably go through quite a few of em and not sure how good of a job it would really do.

wherm5150 11-17-2010 11:02 PM

If I could go back and do my basement differently I'd have someone come in and sprayfoam it. So that option gets my vote. I think it's the most effective way to insulate that area, however, not knowing what it costs to have it done makes it hard to say for sure whether or not it's worth it or how long any energy savings would take to pay for itself. Something to consider...

High Gear 11-18-2010 12:08 AM

I had all mine cut on my table saw in a couple of hours and that was for I-joists ( so notches ).

I doubled up 2 inch foam so 4 inches total thickness ...R20

I cut them just a bit small so to allow for any joist spacing variance.

I used great stuff window low expansion for my glue/sealer.

This can be messy and I would just use PL300 if I did it gain .

Great stuff isn't so great when you get it on your clothes or skin .. I use it at times but reluctantly.

With most basement walls at R-18 and R-20 sills basement temps are between 8 - 10 f of the main level so it all helps ( without turning on the basement registers ).

jklingel 11-18-2010 12:53 AM

I vote w/ concretemasonry and highgear. Keep some acetone around (nail polish remover) to wipe off the Great Stuff if it gets where you don't want it. Hit it right away; acet will dissolve the GS. I use it to wash out the nozzle on the GS when I'm done and have half a can. j

gma2rjc 11-18-2010 01:18 AM

I got some Great Stuff foam on my wrist a few days ago and Skin So Soft from Avon took it off with just a little bit of scrubbing. FWIW.

Red Squirrel, I ordered a 2-part spray foam from the Foam It Green website and I'm happy with the results. Once you have everything prepped and ready to go, it's very quick and easy.

They have several sizes to choose from.

I ordered the 602 since I didn't know how many square feet I needed to spray. I was spraying the soffit areas on my house. I had enough left over to spray the rim joists in my mom's basement and ran out while I was sealing her attic. It lasted a long time.

This was the first time I'd used anything but Great Stuff, and I found it to be a simple product to work with. You do have to have everything ready to go before you spray though because once you stop spraying for 30 seconds, the foam inside the tip of the gun cures and you have to change tips. But that's not a big deal as they send extra tips in the kit. I ordered extras too because I knew it would take me more than 30 seconds to move my ladder and scaffolding.

You do need to cover everything under the area you're going to spray. The stuff is a little bit messy. Just like Great Stuff. In the kit that is included with some of the tanks, they send a Tyvek suit to cover all of your clothes, goggles, shoe covers and extra tips.

And it's made in the USA.

I'm pretty sure there are other companies you can order the same type of product from that are just as good as Foam It Green.

I still have to ask the lady who does my taxes if this will be eligible for the energy tax credit.

Hope this helps.

jklingel 11-18-2010 01:44 AM

gma: good info. I will have to research it. j

AndrewF 11-18-2010 01:45 PM

I too ordered the 602 and will be spraying it this weekend.

I am spraying my rim joists and overlapping the 2" rigid insulation on the basement walls.

I will then use the rest on other areas of the house and out in my workshop.

I'll post pictures later (before/after).

gma2rjc 11-18-2010 10:01 PM

AndrewF, if you wear glasses and the goggles cause them to fog up, keep the goggles on or wear an old pair of glasses. I have a lot of very fine specs of foam on mine now and it doesn't come off the lenses. Although, I haven't tried the acetone or Skin So Soft on them.

Red Squirrel, good luck, whichever way you decide to do it. You'll be glad when it's done and you see the difference in your heat and/or cooling bills.

Since I started weather proofing my house in November of 2008, my gas bill has dropped from $131 per month on the budget plan, to $54 a month. They adjust it about every 6 months.

That's not just because of the rim joists being insulated as I've done a lot of other things to the house, but I'm pretty sure it had a lot to do with it.

Let us know what method you decide on for the rim joists.

burnt03 11-18-2010 10:03 PM

Quote:

Originally Posted by gma2rjc (Post 536693)
AndrewF, if you wear glasses and the goggles cause them to fog up, keep the goggles on or wear an old pair of glasses. I have a lot of very fine specs of foam on mine now and it doesn't come off the lenses. Although, I haven't tried the acetone or Skin So Soft on them.

Red Squirrel, good luck, whichever way you decide to do it. You'll be glad when it's done and you see the difference in your heat and/or cooling bills.

Since I started weather proofing my house in November of 2008, my gas bill has dropped from $131 per month on the budget plan, to $54 a month. They adjust it about every 6 months.

That's not just because of the rim joists being insulated as I've done a lot of other things to the house, but I'm pretty sure it had a lot to do with it.

Let us know what method you decide on for the rim joists.

What other things have to done to weatherproof your place?

AndrewF 11-21-2010 09:35 PM

We completed the spray foam project lastnight. I guess I put it on extra "thick". We have 162' linear feet of rim joist.

I put 98% of my 602 DIY spray foam kit on it. :) Which is fine with me, I wanted to make sure I had it sealed up really good.

http://lh3.ggpht.com/_nzxZK41lpCA/TO...-50-09_768.jpg

http://lh6.ggpht.com/_nzxZK41lpCA/TO...-48-06_671.jpg

bob22 11-22-2010 01:20 PM

ANdrew, what was the finished thickness of the foam over the 162'?
Presumed r value per inch?
cost for the kit?
TIA,
Bob

AndrewF 11-22-2010 03:33 PM

It is reportedly R7 per inch.

I went thick in some of the pockets, because they were missing the cross board, its probably 4-5" thick.

On average I probably went 3" thick. I also sprayed inside an old fireplace that the chimney was cut to below the roof line and then capped off. It was not airtight and a draft could be felt in the winter. So far, there is no air movement coming from it anymore.

I spent around $700 last year on the kit and just now got around to using it.


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