Cement / plaster on internal walls coming off

[oliveview01]

What causes the cement / plaster on walls to come off? A big bit has ' blown ' on an internal wall, the room is not damp it is well aired. A nice repair job

[Martin Page]

Damp is my bet .. even if there is no sign of it.
Unless - its a ground level and then it could just be ants. They user there formic acid to dissolve cement and over time ... an ant - ' can move a rubber tree plant' . I had that I'm my garage - you'll only know when you burst the 'bubble'

[Torrox_campo]

Could have been caused by inferior plaster or that part of the wall hadn't been sealed (primed) properly before the plasterer applying the plaster coats. I'd suggest that you get some PVA adhesive then mixed with water, ratio 1 to 4 or 1 to 5 the smaller the ratio the better the seal, then brush it on the patch before applying the repair plaster, you must wait for the PVA dried before commencing the repair. You can also pour a bit of this PVA into the repair plaster for better adhesion but not too much as the plaster will dry out very fast.
You should apply a coat of PVA before decorating ie.painting or wall papering.

[olive]

Have a look outside and see if there is a cause of damp entering. It is no coincidence that a lot of older houses have tiling inside up to waist height on the ground floor. Things to look for- earth piled up against a wall, metal bar going into wall to support grapes, general slope in direction of that area, gutter leak.

[oliveview01]

We looked for the PVA glue, what name does it come under here?

[Torrox_campo]

You can search for Unibond PVA alternative. From this forum you need to ask for "cola blanca para hormigon":

http://www.fincasinspain.co.uk/viewtopic.php?f=2&t=208