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Black and gray mould on floor joists after leak (1st floor)

Postby dgorissen » Wed Nov 24, 2010 11:07 am


I would appreciate some advice on some mould I have noticed on a couple of floor joists on the 1st floor.

Photos are here:


* over a period of 2 weeks we had 2 leaks relating to a poorly capped pipe after removing a radiator
* the water sprayed onto the carpet and seeped under the floorboards, over the plaster lath beneath (this is on the first floor) and down the electrical light socket into the room below.
* Its hard to guess how much water leaked into the floor, a very rough guess is 20-30 liters
* we shut everything off properly, removed all the carpet and let the room dry with (after a few days) a dehumidifier for about 1 week

Now the situation is:

* I lifted a floorboard under the radiator and inspected the joists beneath
* I noticed a gray fluffy ridge of mould, running along the bottom 2-3 cm of two joists. The plaster lath between both joists also shows some grey mould
* the other joists seem ok and dry (though I have not yet lifted more floorboards to be completely sure). It seems that the two joists and the area in between that got the most water are most affected by mould.
* I also noticed, further down the room in a different part some patches of black mould near the top of a different joist (strange since I dont think water reached here)

On the whole the mould seems mostly on the surface as the joists themselves still look quite solid and dont feel soggy (perhaps slightly soggy in the area closest to where the leak was). But I do not trust the situation and want to be sure the mould will not spread before I put down carpet.

The dehumidifier is still running but as its a small domestic unit it may take a while to really dry things out (or maybe its simply not good enough?).

My best guess: continue drying with dehumidifier, pull up a few more floorboards & paint mould with wickes fungicidal wash, and wait until everything seems dry.

Any thoughts as to how I could speed this up or how to know for sure its ok? Ideally we would like to move into the room (finish decorating, put carpet) in the next 2 weeks.

Many thanks,

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