damp porch

[pamcel]

My parents house has a brick built porch with a flat roof which is showing black marks along the bottom of the wallpaper on the outside wall. They recently had a full length double glazed window installed, replacing a single glazed one with an expelair window vent, and the bottom of the glass is also wet. The porch is two steps up from the garden, and the flat roof seems to be the grey fibre glass stuff rather than felt, and there is no water mark on the ceiling. They have a solid well-fitting front door too, but no heating in the porch, but it's only about 4 x 4'. Is there anything we can do to improve this? They only wallpapered it 3 months ago, and the paper's ruined.

 

[JohnD]

start by ventilating it. You say the glass is wet which is condensation.

If it has a floor without DPM then water will be coming up through it and this will make the enclosed space damp. Any warm moist air coming from the house will also cause condensation..

If there are roof leaks they will tend to show at the top of the walls.

If the walls do not have a DPC they will be damp at the bottom

One way of ventilating it would be to drill holes in the walls on opposite sides to encourage airflow.

I gather from what you say that the old window had a vent, this was probably done because of dampness in the past.

 

[noseall]

if it is a porous, single brick porch, then you may be fighting a losing battle.

 

[pamcel]

I thought the porch may have had it too, but no-one else in the area has removed their porches, or done much other than having the flat roof replaced. The double glazing company told them that the vent was causing the damage! My mum has phoned them to come and inspect it, so we'll see what they say.

Thanks for the advice.

 

[r896neo]

I'd be pretty confident its mould from condensation as mentioned. Try to ventilated it somehow. If its not heated and the inner door is well draught sealed, a vent would probably sort it out. That is assuming that condensation is the only problem.

Good luck.