insulating a block wall

[87GN]

I'm in the process of replacing the drywall in one of my rooms. The bottom three feet is cinder block. The top is at ground level. Should I insulate it before screwing on the drywall? 1/2" foam block glued to it then R15 batts? Or, use 4 inch foam? Do I add a vapor barrier before the drywall? House was built in 1960 and only drywall nailed to the 2x4 framing. Thanks.
Mark

 

[billconner]

The 4" of foam is nearly moisture proof. Block and foam is about as durable as it gets.

But I feel I may be missing the alignment of the drywall over the block versus over studs? Only to suggest you could insulate on exterior with foam, albeit requiring to digging it seems.

 

[PopcornSutton]

If the top of the block is open and accessible, you can fill them with perlight.

 

[rebelranger]

Cmu[block] let's air and moisture through it like a straw. You really should go with closed cell foam on the inside and moisture barrier paint, bare minimum, on the exterior.

 

[billconner]

It might be worthwhile to tape a piece of clear plastic to a section of the wall - maybe 2' square - and see if moisture collects.

 

[75gmck25]

My basement CMU walls have moisture barrier paint, then 2" Foamular sheets glued on, with all the seams taped. That was to prevent ground moisture from coming through the CMU into the room. Then we framed a 2x4 wall and filled it with rock wool insulation (maybe overkill). YMMV.

 

[87GN]

Thanks for everyone's input. Removed the drywall from the lower half this morning. The vertical pieces of wood are nailed only at the top. I think I'm going to replace them. How do I secure the bottoms to the cinder block? The wall is dry. Should I fill some of the voids with some spay foam then glue on the foam board then new frame then the drywall? A vapor barrier before the wood? Here are some pictures of what I'm working with. And a vintage photo when the house was built. I was 3 at the time.

 

[acer66]

Wow, the wood etc looks great with little to no water damage.

Around here that is almost unheard of with that age.

I still would dryloc the blocks to be sure since they are exposed.

 

[billconner]

I would glue just rigid foam to blocks and build out framing above flush with foam, and install drywall with foam adhesive to rigid foam, and usual screws to wood. I'd stop drywall an inch or more above floor and cover with pt or plastic or vinyl base.

 

[freebirdwelds]

You can get the blue rigid foam with grooves for 1x4's already in them. The foam comes in various thicknesses. We would mount them with a 27 cal. Hilti gun through the wood but you can use tapcons etc..

 

[acer66]

You can get the blue rigid foam with grooves for 1x4's already in them. The foam comes in various thicknesses. We would mount them with a 27 cal. Hilti gun through the wood but you can use tapcons etc..

Nice, first time I hear about foam boards like that.

 

[Firebrick43]

InSoFast panels are the best solution for block and concrete walls

https://www.insofast.com/insofast-p...plications/insofast-products-for-interior-use

The way @freebirdwelds posted above is the second best. Don't put wood against the concrete and make sure the foam has grooves on the back.