Finished basement wall insulation in existing stud wall

[J1mbo01]

From what I can tell, it doesn't look treated.....has some dark areas from previous water.

[J1mbo01]

On most of the walls I am finishing, I can slip the rigid foam board against the foundation. I have decided to do that. There is one wall where the rigid board will not fit behind the studs. Would it be OK if I filled in the stud cavities with the rigid foam board? I would then finish with drywall. Thanks for everyone's help again.

[MrRational]

Originally Posted by J1mbo01

On most of the walls I am finishing, I can slip the rigid foam board against the foundation.

If true then it isn't in against the wall tight enough.

There is one wall where the rigid board will not fit behind the studs.
Would it be OK if I filled in the stud cavities with the rigid foam board?

As previously suggested...
either use spray-in for the WHOLE job or demo the walls and rebuild after insulation.

Rigid XPS on the exterior wall (and properly glued/sealed etc).
Roxul batts in the framing (after wiring and plumbing.
Don't forget to seal/insulate at the band board/sill too.

[K'ledgeBldr]

Originally Posted by J1mbo01

Would it be OK if I filled in the stud cavities with the rigid foam board?

Yes. But, you won't have a continuous vapor barrier. Which in this case is probably MORE important than the insulation itself. Savvy?

[Panu16]

For rigid foam board, how would one wire for an electrical outlet?

[MrRational]

Originally Posted by Panu16

For rigid foam board, how would one wire for an electrical outlet?

The same as with any other wall.. inside the framing.

[InterestedOne]

Originally Posted by J1mbo01

I am planning on finishing my basement. The exterior walls are currently framed and filled with fiberglass insulation that is right up against my poured concrete foundation. I am going to remove the existing insulation, but am wondering how I should insulate the existing stud wall, which is about an inch to 1/2 inch inward of the foundation.

The first option is to remove the studs and framing and insulate the wall with 2" rigid foam board, and then rebuild the wall. I do not want to this is if possible, but will if there are no other options.

Are there any other options that would allow me to keep the existing framing?

The basement is fairly dry and the walls are waterproofed. There is a sump pump that comes on about twice a year when we have really heavy rains or snowmelt.

Any time fiberglass get moist or damp its original R-value is los forever. Period! I recommend removing the fiberglass and install closed sell foam or any varying type. Keep your stud frame. apply and finish.

Hope this helps..

Feel free to research open vs. closed cell foams. Also US Dept Of Energy has done extensive reporting on fiberglass insulation. a few % points of moisture can degrade performance up to 35% of the original R. Original R is estimated at about R 3.1 per inch thickness nominal.