band joist and block webs

winchester_2008December 9, 2008

I am going to have closed cell durafoam sprayed on already framed walls 2 x 4. Should the foam cover the open webs on my block that are exposed? also if some of the studs are only 1/4 inch off block will that create a problem

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The webs on concrete blocks are the solid part of the block.

If you're asking should the polyurethane spray cover part of the block as well as the sill plate and joist ends, "yes." The foam will also fill up the space between the existing framing and the concrete wall.

Filling the voids in concrete blocks doesn't do much for energy efficiency. (See link.)

Here is a link that might be useful: Insulated blocks

    Bookmark   December 10, 2008 at 10:41AM
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If you're spraying the entire wall with cc foam, that's the absolute best, though usually not the most economic, insulation method in my opinion.

    Bookmark   December 10, 2008 at 1:07PM
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I already had fg insulation up and drywall and found condensation. Tore it all out down to the framing and having it sprayed. my concern is some of my studs are only 1/4 inch off of cinder block wall. will they be able to get enough spray behind them to do the trick?

    Bookmark   December 10, 2008 at 4:02PM
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Yes. It goes on as a liquid and immediately starts expanding. Be sure to mention your concern to the installer or his supervisor. Below is a pic of the foam I use.

Spraying BASF closed cell insulating foam
pic: Residential, Design Build Magazine

    Bookmark   December 10, 2008 at 9:06PM
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I plan on cutting blocks of foam board to put in the tops of the exposed block that the sill plate sits on,that way the guy can spray a continuous coverage from the top of the band joist down over the sill over top of the block and down the wall between the framing.any way i can talk to you worthy

    Bookmark   December 11, 2008 at 1:15PM
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The top row of blocks were most likely filled on site with mortar or were semi-solid or solid, so that there's no need to put anything into the blocks.

You can pm if you wish. Click on "worthy", go to e mail option.

    Bookmark   December 12, 2008 at 9:37PM
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