Damp Block Shed- Ventilation Ideas?

[adrach]

Hi,

I’ve recently moved into a house with a block built shed (painted, but not rendered or plastered) which is a real bonus but is extremely damp. I’ve already removed one of the old kitchen units which was next to a wall because it was so rotten and mouldy. I store some tools, paint etc. in there, and would like to store timber in there too but can’t because it gets warped so quickly. The shed has a UPVC door and window (both without vents) near one end, and two air bricks near the roof at the opposite end.

I don’t think there’s anything I can do to stop the moisture getting in, but I’m wondering if there’s anything I can do (cheaply) to solve the damp problem by improving the ventilation? I could leave the window open, allowing air flow to air bricks at the opposite end, but that isn’t really secure. Would installing extra air bricks at the opposite end from the current ones (i.e. by the window) help? If so, is it possible to bodge makeshift air bricks by simply drilling holes in a couple of blocks and putting a mesh grille over them? Does anyone have any other suggestions?

Thanks in advance for any help.

 

[Burnerman]

Minimise the moisture first by making sure the roof is in good order, and then consider waterproofing the outside with masonry paint.
Your idea of admitting air is perfectly sound - make the ventilation at low level, opposite to where the existing vents are. Drill your blocks if you want, but the more air holes you make, the better.
John

 

[adrach]

Thanks for this, John. How far above floor level would you recommend adding the vents? The floor used to be painted, but has mostly peeled now- do you think it's worth repainting?

 

[Burnerman]

Put your vent in the second course of blocks, and if you are drilling try to avoid undue vibration to avoid cracking.
As for the floor, maybe the paint has come off due to the damp that's coming up from there? Look at the Perma Gard range of suitable brushing products, that could be used to keep the dampness down.
John

 

[adrach]

Thanks again!