Lath and plaster ceilings: repair or replace?
Common in houses built before the 1930s. How to tell what you have, what goes wrong, and your options.
Before plasterboard, ceilings were made by nailing thin timber strips (laths) to the joists and pushing lime plaster through the gaps so it gripped behind them. Many Victorian and Edwardian houses still have them.
How to tell
- The house was built before about 1930
- The ceiling sounds solid and dull when tapped, not hollow like board
- You can see timber strips from the loft, with lumps of plaster pushed between them
- Cracks run in long straight lines along the laths
What goes wrong
Over time the plaster loses its grip on the laths, often after a leak or vibration from building work. The warning signs are a bulge or sag, cracks that are widening, or a ceiling that moves when pressed gently. A sagging lath and plaster ceiling is heavy and can come down without much warning, so keep people out from underneath it and get it looked at.
Your options
- Small cracks: rake out, fill and line with lining paper before painting so they do not reappear.
- Loose areas: screw the plaster back to the joists with plaster washers, then skim. Keeps the original ceiling and any cornice.
- Overboard: fix new plasterboard through the old ceiling into the joists and skim. Quicker and less messy than taking it down.
- Replace: take the old ceiling down and fit new board. The messiest option, but right if the laths are damaged or you are rewiring.
Period features
Original cornice and ceiling roses can usually be kept even if the flat part of the ceiling is replaced. Tell us if you want them saved.