finished basement reinsulating


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Old 12-30-09, 08:17 PM
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finished basement reinsulating

first winter in a philadelphia row home. Looking to warm the basement. I noticed when the electric box was replaced the current fibergalss insulation was very thin (dont know the exact R value. Possibly 11 or less). The basement is above ground and the finished section to be reinsulated is protected from the rain and snow by a covered patio. there is a poured concrete wall and and 1 window (maybe 84"x42", brand new installed 4 months ago) The basement is finished with paneling, I just want to take the paneling down install thicker fiberglass insulation and put the paneling back up. the wall is only framed out with 2x3's and the current insulation does not touch the concrete. My question is can I install a greater R value insulation, since I only have 3", or will the insulation touching the concrete be a problem (dont think moisture is a big concern because it is an above ground basement)? looking to do a complete basement remodel in a few years framing out the exterior facing wall with 2x4s and finishing with drywall. but looking for a little extra insulation in the mean time.
 
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Old 12-31-09, 05:23 AM
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If you have room, pull the fiberglass, add a 1" layer of rigid, seal in place, then add back the fiberglass and paneling. Pink or blue will breathe a bit but provide a good extra layer of insulation. If you want to go without the fiberglass, just add more rigid.

The third option would be to remove the paneling and cover the studs with a layer of rigid and replace the paneling. Leaving the fiberglass as is.

Some reading for you, BSD-103: Understanding Basements —

And since yours is mostly above grade, here is a link on issues with brick walls, somewhat related: BSD-106: Understanding Vapor Barriers —

Bud
 
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Old 12-31-09, 05:52 AM
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helpful options bud. Can the rigid be installed against the concrete without a gap? If so I am leaning somewhat toward the option of layering out the rigid to achieve the highest R value without using strictly fiberglass. I assume that fiberglass insulation directly against the concrete poses a problem if moisture gets though the wall correct? thanks for the options and feedback. its been helpful!
 
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Old 12-31-09, 06:08 AM
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In fact, rigid against the concrete is becoming the preferred option as unfaced (no plastic or foil) rigid foam boards still have some ability to pass small amounts of moisture. Enough so they will allow drying. Don't use a vapor barrier anywhere and if you can get a layer over the studs themselves you will reduce the cold that those thermal bridges create. Energy Savers: Vapor Barriers or Vapor Diffusion Retarders

Bud
 
 

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