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nick13 09-09-2010 09:17 PM

Renovating basement, not sure if I should change insulation....
I'm going to renovate my basement, currently there is paneling on the walls, with wood studs and fiberglass insulation. It's pretty old and according to the previous homeowner and inspector, there is no moisture down there which is good. I haven't started taking down the paneling yet, but should the insulation be ok if there's no moisture? What should I look for, how do I know if I should change the insulation, and if I do, should I put some sort of moisture barrier to prevent mold? Could I add a moisture barrier and keep the same insulation? Also, is it a good idea to change to metal studs? Thanks, and sorry for so many questions.

Hube 09-21-2010 01:24 PM

Nick13; Hard to give proper advice without knowing what area you are in . If you are in a mean average winter area of, say zero degrees, then you may require additional insulation.Usually a thickness of 6" will give you an R19 rating. But no less than 4" thick in any case. How thick is what you have now?
Also you should install a 6 mil vapor barrier to all the exterior walls. This vb goes onto the face of the studs and the drywall/panelling is installed over this vb. Since you claim the basement is dry then no moisture barrier is needed, as long as it stays that way.The existing studs should be ok as long as there has been no leakage/moisture.
Post back with some more questions and myself or others will help.

nick13 09-21-2010 07:49 PM

basement insulation...
Thanks for replying, Hube, I live on Long Island. Right now there is Owens Corning R-11 fiberglass insulation, 3.5". The wood studs were put up about 1 or 2 inches away from the wall. I did say there was no moisture down there but I did notice a white powder in one corner of the basement when I ripped up the carpet, which might be salt deposit? I'm thinking I should rip everything down and start from scratch.

In reading about it online, it seems like the pink foam board might be the way to go. Foamular 250 from Owens Corning seems to be the most popular, just not sure what thickness to get. And there seems to be a couple of different ways to install it, glue the boards to the wall, screw ferring strips in the channel where the seams are and sheetrock over it. Or glue the boards to the wall and just frame in front of the boards. And they say a vapor barrier is not needed. Not sure what to do.

Also, there is about 2 or 3 feet of my basement walls that are above grade (I guess that means above ground) and the rest is below grade. I would obviously insulate all the way up, but do I have to worry about moisture in the areas of the wall that are above grade?

Any advice would be helpful.

handyguys 09-23-2010 10:59 AM

If the wall studs are straight and if your comfortable (temp wise) in the basement then I would leave well enough alone. Don't add additional vapor barriers, don't remove any that exist. Just replace paneling with drywall.

A vapor barrier can actually trap moisture and contribute to or cause issues. I'm not saying one is never warranted, it just needs to be right.

Since you are dry now why tempt fate?

If you do rip it all out then do the rigid foam glued to the wall, taped seams and then build a new 2x4 wall in front of it. Don't use furring strips. If you need additional insulation beyond what the rigid foam gives you then add UNFACED fiberglass to the 2x4 wall.

See Info-511: Basement Insulation — Building Science Information for some good recommendations.

nick13 09-23-2010 08:50 PM

Thanks for the info. I will probably rip everything out and install the foam boards with the studs in front. Metal or wood studs? What R-value for the insulation should I get or what thickness? Do the foam boards have to go all the way up to the floor joists even though it's above grade? And what type of adhesive to glue the boards and what kind of tape for the seams? Thanks again for the help.

handyguys 09-24-2010 02:40 PM

I like working with wood. Your bottom plate is Pressure Treated. The link I gave you has details on where to stop the foam board, how to insulate the rim, how to glue the boards and what tape to use. The tape is sold in the insulation section. If you get the pink boards they will sell you a red tape, if you get the blue boards I think those places sell blue tape for the task.

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