What Happens When You Have Rock Lath?


I have several long cracks in my ceiling and walls.

The House is a 1949 Cape Cod.  The backing is NOT lath but it looks like a cement board or another sheet of plaster.

Will Big Wally’s Plaster Magic work on this?

The plaster substrata that you have is called rock lath. The long cracks that you observe run at the border of the rock lath pieces. The rock laths are boards that are 16″ X 48″. The symptom that you see is typical of rock lath aging. It is not a very sound system. As your building moves the plaster cracks along these lines. There is nothing you can do to prevent this, you can only mask it. The good news is that barring other issues it shouldn’t fall down soon.

In order for Big Wally’s Plaster Magic to work it needs two materials to glue together. In this case the plaster is not delaminating from the lath making it a condition where the adhesive will not be useful. If the plaster is coming away from the rock lath or the layers of plaster are separating then you can use Big Wally’s Plaster Magic.


No Comments, Comment or Ping

Reply to “What Happens When You Have Rock Lath?”

You must be logged in to post a comment.