Drying plaster with a heater?

Jan 08, 2004 5 Replies

On TV makeover shows you often see them leaving a few convector heaters on overnight to dry out fresh plaster quickly. Is this bad for the plaster like it would be for cement?



Would it make a difference if you were doing this to a skim of top coat over an old wall or a new partition wall (fresh plasterboard, bonding and finish)?



As long as you're only drying the air in the room, then putting heaters on is OK, but don't point the heaters directly at the walls or you'll cause the new plaster to shrink to quickly and crack it. De-humidifiers are the best thing to use, because they remove the moisture into a bucket ready for emptying.

It's import in the case of both cement and plaster that they remain wet until they've set, otherwise they'll stop setting. Plaster sets quite quickly -- I suspect it's reached full hardness within 24 hours. Cement on the other hand takes weeks to reach full strength.

I think you'd be OK as long as you let the plaster go off fully before you start heating, or at least go off enough that you're happy with the hardness as far as it's got before you start heating. Just a skim on plasterboard wouldn't take long to dry by itself anyway. I would avoid speeding up the drying unless you have some very good reason to do so though.

You need ventilation too of course -- the water in all those bucket loads of plaster has to evaporate and get out. (Actually, I assume some is consumed by the chemical reaction, but I don't know what the chemical reaction sequence is for gypsom plaster.)

What happened to recycling? use that water to make new plaster... ad infinitum

Here we go - is it better to use electricity to extract that water from the air, or to throw that water away and use fresh from the tap? Answers on the back of self addressed postage stamp please... (in order not to waste paper...)

They admitted on one program that they use a special quick drying plaster.

My tapwater is largely chlorine. Water from the workshed dehumidifier goes for the houseplants.

-- Smert' spamionam

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