Mould behind plasterboard in shower?

obriener2054

Any tips on how to deal with this?

The normal plasterboard was used and not the green one that would be used

There was plastic a backing on the back of the old plasterboard too which I reckon was a key to it,

The bathroom hasn’t been used in a year now at this stage...

Anyone any thoughts

Calahonda52

Thats a bit more than mould my friend: looks like wet rot.
whats is the styrofoam doing?

jmBuildExt

was an episode on room to improve series before last where they had to tackle that.
In that case it was an old stone coach house type thing that basically had a insulated structure framed within the walls.
When they pulled the insulation off this stuff was behind it - everywhere in the house. Cant remember where it was - athy rings a bell though.
IIRC it was basically to do with ignoring dew points when putting in the insulation. Yours might only be to do with the fact it was a shower area.

Think there were posts from someone on here too who had it on their concrete floors. He was doing a diy rennovation job and basically found it crawled to more places than he would have imagined. It started from a pipe leaking in the concrete, again if i remember correctly.

diggerdigger

Does look like wet rot alright. Cellar fungus.

Kind of looks like it historic and wasn't treated fully when the plasterboard was put over it. I say that because the wet rot strands are broken, start mid wall where old plaster is cracked. Unless you did that removing plasterboard?

To treat, maybe some boron based treatment after its been thoroughly dried out. I'd rent a drying machine.

You'll probably have to check behind other plasterboard, lift floorboards check woods. Treat all good wood with preservative. Remove all traces of rot.

Double check that you know the source of the moisture. Could be condensation from the plastic backing you mentioned. Whats on the other side of the wall? Is the wall damp?

obriener2054

Pulled more plasterboard from the wall there and I’ve another spot about half the size

Yes I remember that episode of room to improve ....

This seems confined and is in the plaster that was skimmed on concrete wall, which in turn then was battoned and then slabbed with plastic lined plasterboard, all in the shower corner

I’ve been up in the attic plenty of times and have no damp issues from the roof

I’m 99% sure it’s because of the shower, it’s nowhere else in the room

obriener2054

No wall is bone dry, bathroom was just stripped out and then was left near a year ago

All walls in this room are concrete, floor also, the spot where the styrofoam is was on old window blocked up, other side is a bedroom, no issues in there

The Mulk

jmBuildExt wrote: »

was an episode on room to improve series before last where they had to tackle that.
In that case it was an old stone coach house type thing that basically had a insulated structure framed within the walls.
When they pulled the insulation off this stuff was behind it - everywhere in the house. Cant remember where it was - athy rings a bell though.
IIRC it was basically to do with ignoring dew points when putting in the insulation. Yours might only be to do with the fact it was a shower area.

Think there were posts from someone on here too who had it on their concrete floors. He was doing a diy rennovation job and basically found it crawled to more places than he would have imagined. It started from a pipe leaking in the concrete, again if i remember correctly.

I remember that episode, it was the house at the junction of the Dunboyne Road in Maynooth.
As far as i remember they had to replace the roof and floor joists????

TomOnBoard

I didn't know wet rot looked like that. It looks like ivy roots had grown in through the old window in the past and had been pulled off the wall leaving the tracks of where they grew.

diggerdigger

I would chisel off the affected plaster and treat the wood and concrete wall with a biocide/preservative. To be sure, get every last bit, wire-brushing any infected bits you aren't chiseling off.

Did the plasterboard come off a year ago with the strip out and it grew since then, or was the bathroom stripped out a year ago and the plasterboard just came off?

obriener2054

I removed the bathroom suite and tiles etc, last year

Just today I’ve removed the plasterboard and uncovered the mould, it looks as if it was there the last time when the previous owners put the new board up as 2/3 batton’s in from the right you can see the outline of a previous baton

As said the whole area is bone dry now, I’ll be using the water resistant plasterboard and most likely tank the shower area, I think it was a bad decision to use plasterboard with plastic lined inside it also but the mould could have been the reason for using it