Aethos advice
Painting old plaster in a period home
Old plaster can carry cracks, repairs and incompatible coatings from many decades. A refined finish starts by deciding what is stable, what is significant and what should not simply be filled.
By Aethos Studio · Published
Map the wall before making it uniform
Look across the surface in raking light and record cracks, hollow areas, staining, friable patches and different repairs. Fine settled cracks, active movement and detached plaster are not the same problem. Significant movement or widespread loss of key needs appropriate building or plaster advice.
Check the existing decoration
Old walls may carry modern emulsion, wallpaper residues, material resembling distemper or earlier mineral finishes. Powdering, poor adhesion and moisture sensitivity should be tested in a small area. A new coating is only as reliable as the layers beneath it.
Do not seal unexplained moisture
Staining, salt deposits or repeated blistering can indicate water entry, plumbing defects or moisture movement through the wall. Painting should pause until the source is understood and the substrate has reached a suitable condition. A suitable stain block can isolate a dry, stable mark from an old leak. It does not fix an active leak.
Repair to the wall, not a generic recipe
The repair material should be compatible with the plaster and the scale of the defect. Repairs that are too hard can behave differently from the softer plaster around them, while excessive fine filler can create a fragile skim. The written scope should distinguish local decorating repairs from plaster conservation or replacement.
Understand the existing layers before choosing the finish
Some sound old plaster performs well with a suitable modern system; other traditional walls benefit from mineral paint or limewash. “Period property” is not itself a specification. Existing layers, wall construction and moisture behaviour decide the sensible option.
Compare modern and breathable finishesAgree what an honest finish looks like
Historic plaster may retain gentle movement and surface character even after disciplined preparation. The quotation should set expectations for crack repair, local undulation and any areas requiring specialist work rather than promising that paint will make every substrate new.
Explore period home decorating