Hollow-sounding, crumbling or bulging plaster on your walls in Walthamstow? What blown plaster is, why it happens, and how it is repaired properly.
01The knuckle test | Tap along the wall with your knuckles. Sound plaster gives a solid knock. Blown plaster sounds hollow or drummy. |
|---|---|
02Look low down and near chimneys | Blown plaster often starts at skirting level or around chimney breasts, where damp gets in. |
03Crumbling or powdery? | Plaster that crumbles or turns to powder, especially with white salty marks, usually points to damp in the wall. |
04Do not just fill and paint | Filling cracks in blown plaster hides it for a while, but the loose plaster behind keeps moving and the cracks come back. |
05Send us photos | Photos of the wall, and a note of where it sounds hollow, help us judge how much needs redoing. |
Blown plaster is plaster that has come away from the brick or block behind it. You often cannot see it at first. The wall looks normal, but tap it with your knuckles and part of it sounds hollow instead of solid. As it gets worse it can crack, bulge, crumble when you hang a picture, or come off in pieces when old wallpaper is stripped.
It is very common in Walthamstow, because so much of E17 is Victorian and Edwardian terraced housing, including the Warner flats, with original lime plaster on solid brick walls. Over a century, damp, vibration and old repairs with the wrong materials loosen that plaster. Leyton and Leytonstone have the same housing stock and the same problem. Damp is the usual trigger, especially low down on walls and around old chimney breasts.
The fix is to hack off the loose plaster back to sound material and replaster that area, using a plaster that suits the wall. On old solid brick walls that often means a breathable lime based plaster, because modern gypsum can trap moisture and blow again. If damp is causing it, that needs sorting first or the new plaster will fail.
Mostly age, damp, vibration and earlier repairs done with the wrong materials. Old lime plaster on solid brick walls is the most likely to blow.
Not always. Often only the hollow areas are hacked off and patched. If most of the wall is blown, replastering the whole wall is usually neater and lasts longer.
Old solid walls need to breathe. Lime plaster lets moisture out, while modern gypsum can trap it against the brick, which can make the new plaster blow again.
Usually not, though loose plaster on a ceiling or high up can fall. If a ceiling sounds hollow or sags, keep people out from under it and get it looked at.
Send a photo or a quick video of the room on WhatsApp. Or ask for a free fixed quote with no obligation. We will tell you straight what it needs.
