Single skin brick shed has damp/mould on internal walls - options?

[Arjay12345]

Hi - I had a new brick shed built in my garden two winters ago, and my mistake was keeping it as a single skin brick wall for the sides and rear. All internal walls have been skimed and painted but I'm now getting damp especially where I have shelving against the walls where air can't circulate.

What options do I have to stop the mould? If I line the walls with batten frame and fill voids with insulation, will that cure the problem? The shed is fairly small, so I cannot afford to go deep with the insulation. I don't mind the top layer being 12/18mm ply (instead of plaster board) as I can also screw things directly into that too.

Thanks very much

 

[Bonni]

A brick is 215mm in length and half a brick is 102.5mm. The correct terminology for your shed wall is it's Half Brick.

That aside, a brick wall doesn't keep the water out, even on a house; hence a cavity, cavity trays, wall ties with drip areas, weep vents etc..

Anything touching the inside of the brick will be subject to the damp coming through. So you would have to put a plastic DPM sheet on the wall, screw battens to the wall (say roof lathes) and then screw your ply to the battens.

 

[^woody^]

The correct terminology for your shed wall is it's Half Brick

The correct terminology is single skin, as per the title.

 

[^woody^]

Your problem seems to be condensation related, not penetrating damp - although there could be both.

Insulation and ventilation would be required. There are lots of shed threads on this, it just depends how far you want to go with the work, but unless you heat the place, you wont ever stop condensation.

 

[Arjay12345]

Thanks all. So I'm about to ask a probable dumb questions...

In building a stud cavity layer per my original post, would the mould be reduced because...

a) the internal wall (plasterboard or ply) is no longer physically touching the brick surface if a DPM sheet is used? (so there would always be mould on the inside brick surface but I just wouldn't see it because it can't travel to the inside surface)

OR

b) the void itself create a warm(er) barrier and so mould is reduced on the internal side of the brick wall itself too?


If it's a case of a bit of both, does one help more than the other?


Thanks

 

[^woody^]

Theoretically, the insulation plus the warmer surface that you line the internal face with, will raise the dew point (the surface temperature at which condensation forms) and reduce condensation forming. But in practice, the air will still be moist and that may well find a surface to condense on - or in, in terms of timber board or plaster board.

It may well be an improvement, but results will be unknown. You may well reduce condensation and mould to a minor level, so it's probably worth having a go, but ventilation will almost certainly be needed too.

 

[StephenStephen]

Have you thought of insulating the outside?