Seeking Advice on Exterior Walls

[catchyname]

Began to tear down walls for a small remodel and discovered quite a few problems and oddities, one of which was the block runs all the way up to the roof, and on the main floor there was simply plaster applied directly over the block. You can see in the picture to the right the exposed block around the small bathroom window.

My question is moving forward with the remodel do I need to remove the plaster and put up framing/insulation or can I simply plaster over the block as was previously done and call it a day?
If so, how major an impact would this have (not framing out and insulating) on energy costs?

Looking for general thoughts/ideas/observations/pros/cons etc., thanks.

 

[Snoonyb]

If the space is comfortable just plaster and go on. If not, and you are comfortable loosing the area a build out will cost you, then do that.

 

[catchyname]

I’m not comfortable losing the space the build out will require it’s a small floor plan. The basement is a different story I believe I will have to build out and insulate due to moisture coming through from being underground, would you agree? Or is there other options not requiring a build out? I would assume the plaster would just take moisture as well, am I right?

 

[Snoonyb]

So you are speaking of two different location within the same dwelling, basement and the area in the photos.

In the basement you'll need a drainage system.

In the room in the photo's, it appears the construction of the exterior walls are CMU, which can be successfully plastered, unless they are below grade, which then would require an exterior waterproofing system.

 

[catchyname]

You are correct.

What kind of drainage system would you recommend?

So if an exterior drainage system was implanted then the CMU below grade can be plastered as well? Or should it need a drainage system as well as the building out?

Thanks.

 

[Snoonyb]

If your basement walls are leaking it's probably caused by the exterior landscaping and/or the water from roofs and gutters not being directed away from the dwelling and that's where the first efforts should be.

Next there are any number of interior corrective measures, from cutting a channel in the slab to overlaying the slab.

If there is no evidence of moistures intrusion, now, does not mean that there won't be in the future, so do all that you can to keep water away from that wall. You could excavate that area, resurface the waterproof membrane and install a French drain.

 

[bud16415]

In the upstairs area I think I would cover the block with a vapor barrier and then do furring strips 1x3 16” OC. Between the strips I would fit ¾ foam insulation cut to fit and then cover the whole wall with ½ drywall and finish. Doing full plaster over block is not a typical DIY job and you will only loose ¾ of an inch furring it out.


If you live in extreme cold then giving up more space for thicker insulation would be logical.