# Does drywall mud stick to paint?



## Black Jaque Janaviac (Sep 18, 2012)

Last year I set up my NC-30 in the basement and used leftover mortar to make a Venetian plaster look behind the stove.  However, the prep work was extremely tedious as I had to remove paint from cinder block.  It was OK for that area directly behind the stove, but I really should continue the job around the rest of the room.

Mortar won't stick to the painted cinder block.  I don't want to spend the jing on covering the wall with metal lath.

I'm wondering if I can just rough up the paint with coarse sandpaper then cover it with drywall mud.  Would that work?


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## Jags (Sep 18, 2012)

Drywall mud WILL stick to paint (stick to the green lid stuff, more glue) BUT - you will have to keep in mind that the compound sticking to the wall is ONLY AS GOOD as the paint it is sticking to.


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## ironpony (Sep 18, 2012)

I think we already beat this to death if I remember correctly but why not insulate the walls and fir out drywall which you can then plaster. the walls are a giant heat sink. and to answer your question I agree with Jags's answer


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## Black Jaque Janaviac (Sep 18, 2012)

Because foam insulation ain't cheap.  My plan is to insulate, from the outside, just that portion of the wall that is exposed to the air and maybe a foot below ground.  By doing that I should eliminate the worst of the heat sink with only a few panels of foam.  I will wait and see if just that amount of insulation is sufficient to keep the house toasty warm before finishing the basement wall.  If insulating the exposed part of the foundation doesn't do the trick I may have to insulate and drywall as you suggest. 

Right now I'm just checking my options. 

Oh, and the paint is stuck to the block very well indeed - if it wasn't I'd have no problem removing it to expose the block and just continuing with the mortar parge.  I don't have moisture problems - except condensation in the early summer.  Very sandy soil with over 10 feet to the water table.


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## begreen (Sep 22, 2012)

Partial insulation is going to be a partial solution. The uninsulated portion is still going to suck out a lot of heat.


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## save$ (Sep 22, 2012)

The r factor on foam exterior wall insulation I don't think will offer you what you are hoping to acheive.  Foam on the outside has to be coated or it will deteriorate from light.  Also if your home was not disigned to have the foam, it may be an issue were it meets the house siding.  There is the issue of moisture. You are going to need to have a vapor barrier from the ceiling to the floor, and insulation, either interior or exterior.My wall are well protected in my lower level, but my floors are not.    I put exterior drains at the footing and have interior drains around the inside of the footing. My wall all coated, then an air space, then studs and insulation.  So I spend a lot of energy in the summer keeping dampness out of my finished living space, never wet, just too humid.   Anyway, you can find you answer easily on the DYI networks such as HGTV.   Since you live where the winters are cold, your heat loss factor is significant without proper insulation and moisture protection.   To your original post,  use a good wall cleaner and rinse off. Then use a good primer.  Your plaster shoud set without problem.  If you have any hint of black mold, you have a moisture problem that will need to be fixed first.  I think you will find that drywall plaster will suck up moisture from the cement walls and will flake off in a few years.    Insulation is the investment that keeps paying back year after year.


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