The walls in my 35 yr old condo are plaster over concrete.
From time to time plaster bubbles occur - usually following a
summer of high humidity.
What is the best method/solution for repairing these.
We do a lot of Plaster repairs, and this is a common and often incorrectly repaired problem Plaster is Not Drywall and many times we go into a home after some contractor has tried to fix this by simply patching the bubbles with drywall mud or sheetrock product and this later creates a new problem.
When we are this situation we remove the damaged plaster and any paint around the area if this opens up to a hole or large area a scratch coat is applied , once dry the area of scratch coat or concrete is treated with conditioner so new plaster will bond, and is coated with a topcoat or gauging plaster then sealed and painted.
Don't let anyone trick you into putting drywall compound on Plaster walls it is NOT the same at all and will flake and fall out, the same for Plaster of Paris, the plaster you have is a Portland cement, Lime Putty and sand mix. That any qualified contractor can get it is readily available but not sold to just anyone, because there are specific install steps that must be followed.
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