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Forever_Remodeling 08-22-2010 01:59 PM

Insulating Basement Walls
I want to insulate my concrete block basement walls with foam board insulation, and use furring strips to install paneling. My question is

1) Iinstall the furring strips 16" on center and insulate between each strip?

2) Insulate the entire wall first, then place the furring strips on top?

If (2) above, then what do you do with the gap that will end up between the foam board and paneling?

Lastly, using foam board, is it still necessary to use a vapor barrier? I know it is if using fiberglass batting, but not sure if needed with foam board.

GBR 08-23-2010 08:09 PM

I think Formular 250 has the space at the vertical joints for the furring strip to be recessed. If not, fill the space with another layer of unfaced foam board to eliminate any convective loop from the airspace: Insulating with Fiberglass Batts - Oikos Green Building Library
Info-501: Installation of Cavity Insulation — Building Science Information
Use a sill sealer under the p.t. bottom plate for a thermal and capillary break from the concrete slab: Pressure-Treated Sill Plates and the Building Code |

No v.b. below grade, it needs to dry to the inside there.

Be safe, Gary

mudmixer 08-23-2010 08:54 PM

Avoid fiberglass because the ability to hold moisture, which reduces the insulating properties dramatically can feed moisture to the wood and drywall that can cause mold growth.


Forever_Remodeling 08-24-2010 02:03 PM

Thanks for all of the info!

My last question would be how does one drop an electrical line down for outlets and/or switches on the wall? Can I just "carve out" a small section of the foam and run the wire down through it? I shouldn't need to carve out the whole depth of foam, just enough to make the wire flush with it. Is this allowed? My vision was to run the electrical line up around the rim joist and have a junction box where I can drop a line down to an outlet instead of running the line all around the bottom half of the wall. I will have a suspended ceiling to have access to the junction boxes. None of the boxes will be "hidden".

GBR 08-24-2010 05:26 PM

Wiring a basement of insulated concre... | Breaktime

Be safe, Gary

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