I have a house with walls which are in pretty good shape. There a few areas with small cracks and dents.
Background – The house (in central NJ) was built in 1923 and the walls have what seems to be a 1/4″ thick cement type board nailed to the studs. On this is a coating of 3/8″ thick hard grey cement looking substance. On top of this is plaster or joint compound about 1/16″ thick. There appears to be no lath underneath any of this.
First question – What is this stuff and how do I repair it?
Second Question – Can I skim coat over it to fill in any of the small (1/16″ wide) cracks. Will the famous D-mix work to do this. What kind of prep work do I have to do to skim over the existing painted walls?
Thanks,
Rich
Replies
Get a crack tool at your local paint store....it's a triangular bent over head on a handle (not a paint scraper), and some Durabond 90 (or easysand 90)
Dig out all the loose plaster in the cracks (if you can scrape so that the groove is wider at the bottom, that's good, but not essential)
Mix the Durabond per directions (don't mix much at once, mixing the powder into water works better for me)
Fill the cracks, let harden, use a second coat of regular premixed joint compound...
Other posters will notice that I've left out using any tape (either mesh or paper)...and will say you must use it..
Who knows-my experience has been that sometimes no matter what you use the cracks can come back (sometimes the next change in seasons, sometimes after years...and sometimes they never come back..
that's it in a nutshell....everything else is technique + experience
I imagine the board is some form of "rock lath".
BTW, a can opener (church key) works well for scraping out cracks.
thanks for the replies. I'll have to practice in the closets.
Rich Knab
People of mediocre ability sometimes achieve outstanding success because they don't know when to quit.