HELP: drying out wet plasterboard

MassiveJim

MassiveJim

MassiveJim

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22 Feb 2014
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I caused a leak in an ensuite bathroom a few days ago that had mains pressure hot water spraying into the room for 30 - 60 seconds roughly.
I turned off the water and then mopped the floor and left a fan running overnight.

next morning the ceiling in the room below had some staining on it over a fairly large area maybe 1.5 -2 m2
the issue I have is that the room below after a few days smells of damp plaster still.

I have had fans blowing in both the bathroom and pointed at the celling in the room below.

I have a portable aircon with dehumidifier function that I can try, would this be better in the room below or the bathroom itself ?
anything else I can do short of ripping up the bathroom floor (its kardean over 3mm ply, which would also need removal of a toilet so not keen on this idea)
 
It will dry out, just might take a while, this hot weather will help.

When you have water damage professionals will provide these large fan heaters, sometimes they have them in pubs, and you leave those running for like a week sometimes longer.

If you keep it well ventilated given this weather it will dry out. Give it a few weeks then you should be ok to paint over the water stains.
 
MassiveJim said:
our eldest daughter is currently sleeping in the room and the missus is worried about the damp making her ill, is she over reacting ?
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The health issues come from damp and mould, not really 2 days after exposure to clean water. If you've got the de humidifier going your daughter is probably breathing drier air than normal.

60 seconds of mains pressure water is quite a lot and the staining probably wont go away on its own so once the room is dry which could take weeks or months you can remedy it. Get a cheapo moisture reader.
 
The decorating side of things I'm not worried about, pretty much every ceiling downstairs needs filling and painting anyway. Had a radiator leak in another room last year and there is still staining on the ceiling from that as well.

had floorboards up in various rooms and walking about on the joists has caused plaster to come off the nail heads in various places.
I'll get round to all of that eventually.
 
Open the windows in the room below during the day, and ventilate with fans in that room, to push the moist air out.

At night, put the dehumidifier on in the downstairs room once it is cold enough to have the window closed. You need the window closed for the dehumidifier to be pulling moisture out of the ceiling.

There's no health risk until it's left damp for a while and black mould starts to grow, but this shouldn't happen if you do the above.
 
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radderfire said:
Open the windows in the room below during the day, and ventilate with fans in that room, to push the moist air out.

At night, put the dehumidifier on in the downstairs room once it is cold enough to have the window closed. You need the window closed for the dehumidifier to be pulling moisture out of the ceiling.

There's no health risk until it's left damp for a while and black mould starts to grow, but this shouldn't happen if you do the above.
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annoyingly there is no window in the room, just a double sliding patio door. and the dehumidifier will need to vent outside I assume. I'll have to check the manual
 
I would cut out the ceiling from below, and reboard it. Assuming it's not that massive an area, it won't be that bad. Tape and fill the joints, repaint. Or pay a plasterer to do it, it should be a 1 day job (although you'll have to paint it, rarely will you get a plasterer paint).
 
MassiveJim said:
annoyingly there is no window in the room, just a double sliding patio door. and the dehumidifier will need to vent outside I assume. I'll have to check the manual
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Dehumifiers just circulate the air inside the room, and deposit the moisture in a tank.

If it vented outside it will pull air into the room from somewhere and defeat the object.
 
I've set the dehumidifier running in there. It doesn't have a tank though so it's draining in to a bucket, since about 6pm it's put about 2 inches of water in the bucket, so should be safe to leave it running all day tomorrow whilst I'm at work
 
From my personal experience, fan to push air out of the room is the most effective. Even better than running dehumidifier, we even take out all the light fittings.



 
When I worked in the tools game some years ago on a flood there was always a massive rush for two things,
Fans and dehums

Fans to move the air around and the dehums to collect the water.
The air movement is necessary to get the moisture wicked away from the wet area, the dehum obviously then catches it.

If it was cold then a third item would go out as a "pack", a heater.
The heater was needed to warm up the air to increase the ability of the air to hold the moisture.

This time of year you don't need the heater just the other two.
 
Pop a few small holes in the plasterboard below will also help you get air movement in the void between the two surfaces.

They can be easily filled once it’s dry.
 
I've left the dehumidifier overnight and the room is incredibly warm so it's obviously got a built in heater. I'll see how it goes, trying to avoid holes in the ceiling if possible, but I haven't ruled it out completely yet
 
MassiveJim said:
I've left the dehumidifier overnight and the room is incredibly warm so it's obviously got a built in heater. I'll see how it goes, trying to avoid holes in the ceiling if possible, but I haven't ruled it out completely yet
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Probably not a heater, but they were iirc hardly low energy, (like 300w or something from memory)
 
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