Plaster - Fire Cracking?

[IED]

Hi, I had a bathroom wall skimmed today (to be tiled over) by a professional and crazy paving hairline cracks have appeared over the entire wall as the plaster has been drying out. Having spoken with him, he says it is nothing to worry about and that it is called fire cracking; where the plaster dries out too quickly. (The room is very warm). He states his reputation that it is well bonded and that I will have no problems tiling over it. If it is a cosmetic effect then it doesn't bother me but if it is a bonding issue then the last thing I want to do is to tile now to watch it fall off later!!! He has over 40 years plastering experience so I should just believe him. However I would like to see if there is a concensus of opinion. Hence my question Should I be worried about the cracking or am I being foolish doubting an experienced tradesman?

TIA

Ian

[The3rd Earl Of Derby]

Plaster will crack if the room is too warm when its drying out. This effect is common on chimney breast if the chimney has been used with a gas fire. If you're tiling on it no problems,but if the cracks are above the tiling you should by all means be annoyed as the plasterer should know the room has to be cool when plastering. 40 years,hmmm!

[The3rd Earl Of Derby]

oops! forgot to ask did he plaster over old plaster which was painted? Also if a thin layer of plaster has been applied this will cause the cracking as well.

[IED]

Many thanks for the answer.

He plastered over the old base coat. I removed the top coat as it was badly damaged when removing previous tiles, so no paint. Yes it was a thin top coat just to make good the wall. There are a couple of areas that haven't cracked where he had to apply base coat as well.

Glad it doesn't affect my tiling. I was worried that it wasn't bonded.

Ian

[sim]

Happens to me sometimes with old dry high suction backgrounds that take all the moisture out of the plaster too quick. I only have 5 years plastering experience but I find that the background is more a cause than room temperature and I can usually anticipate and avoid it now. After 40 years he should know better!

Will be ok behind tiles but I have seen it show through paint before.

sim.