# turning heat on after plastering



## johnnyg (13 Oct 2008)

how long do you have to leave the plaster to dryout before you can turn on the het in the house, this is a new build and we will have geothermal, the builder is putting 12 weeks before turning on the power and finish plastering, surely it would make more sense to turn on the heat once the second electric fix is complete, pre xmas?


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## NOAH (13 Oct 2008)

an age old question,  you need to let the palster dry natyrally ie open windows if weather permits, dry it too quick and it will shrink and crack. depending on outside temperatures 6 to 8 weeks should be sufficient but dont rush it.  so 12 weeks is a good guide

using a humidifier will draw out moisture as well.

noah


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## angela59 (13 Oct 2008)

Hi,

After having two ceilings replastered in an existing build and I didn't use any heat for them to dry out left windows open where possible and I still got a big settling crack - so my advice to you is let it dry naturally or use a humidifer - you will be kicking yourself otherwise - took 2 to 3weeks for a reskim on ceiling to dry out properly.

Angela59


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## mad m (13 Oct 2008)

Some would suggest 6weeks to fully let plaster dry out. Others would say as soon as it goes white or 7days. Put it this way, after 7 days it looks fully dried out and you paint away. You wack on heating and small cracks appear in plaster (It does happen). After a good few weeks you have settlement cracks and drying out cracks.

So you might have to refill some cracks and repaint (up to you how fussy you are).

If you let it fully dry out and some cracks appear before painting then you can fill them and be sure that no more cracks will appear. Now you will get the usual cracks, like over a door frame from door shutting etc.....


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## sabre (15 Oct 2008)

Using a dehumidifier makes the environment drier, so allowing moisture to pass from the plaster to the inner environment. If the windows are open during this process, the dehumidifier will be continually drying the external moisture laden air as it enters the house. Also take care that a dehumidifier is extremely effective , so you should use it carefully.

sabre


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## johnnyg (16 Oct 2008)

i don't intend to paint straight away, but what i want to do is turn on the geo for the UFH to dry out the house and was wondering how many weeks post plastering can you do this without doing damage, i know that you will get some cracks but one person said that if i turn it on too soon that it will cause cracks all over the plaster and its this "too soon" time i am looking for..cheers for info to date


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## sfag (16 Oct 2008)

the plaster is dry once it goes white - 1 week. The plaster will crack regardless. Give it the 1st two coats of paint whenever and the last coat a year after you move in.


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