why does new plaster on walls always crack?

Question

when someone reskims a wall why does the plaster always crack after a few weeks, they say it shrinks is this correct, how can i prevent this happening, thanks

Answer 1

open the windows and doors to allow natural drying as a warm environment will cause quicker drying which will add to the shrinkage cracks.

Answer 2

Generally this indicates too much water in the mix, or the layer was applied too thickly. Plaster needs to be applied in thin layers and built up rather than being gobbed into the patching area. If the cracks are big, there should be a piece of mesh ( the self- adhesive type works well ) applied before the mud, so it will have something to grab onto. No driers should be added in the mix either- it should be allowed to dry naturally at room temperature, and during the drying process, the temperature should remain constant if this is possible.

Answer 3

Wrong plaster, I suspect. I resurfaced the walls in an entire room with DuraBond joint compound... minimum 4 coats... about 20 years ago and still have no cracks. DuraBond is barely affected by humidity, Check with your local hardware store or any good DIY site on the internet. Search "resurfacing walls."

Kabum

Answer 4

It does shrink, but a decent pasterer will skim it in stages, push much of the air and water out of it as its polished.

They can crack, but its not inevitable.

We've just plastered hall, dining, stairrs, bed 1, bed 2 and front reception, inc all ceilings. combination of solid walls, stone walls, and lined walls.

I can't think of anywhere it cracked.

Answer 5

Usually its because the temperature in the room has been risen too quickly drying out the moisture too fast making the new plaster brittle.

Answer 6

It is better to let the plaster dry slowly but it is quite hard to avoid the odd crack, most new builds end up like polyfilla villas.

Answer 7

It dried to quick
they didnt mix the plaster correctly
the 2nd answer is the one

Answer 8

This is because the water content of the plaster evaporate too quickly due to excess heat. turn down the heating! else you have lots of gaps to fill on your walls!

Answer 9

plaster settles and the pressure will cause cracks at the weakest point...try grooving the crack to relieve the pressure, then fill with perf compound(sheet rock perf).....and I believe moisture under the paint will cause blisters, or there wasnt a good prime coat put on first....hope this helps...good luck....

Answer 10

Too much water in the original mix.