Dampness in brick shed

[Padraig Clarke]

I have a brick shed attached to my house via a lean-to. Bought the house in June last year, no problems until the colder weather kicked in. I noticed a condensation problem on the back wall. Now I've seen mold growing on stored furniture. I have posted some pictures. I wonder if anyone can give some advice?

 

[r896neo]

I assume its a single skin shed?

Realistically it will never be totally dry without spending a decent but on it. You could try increasing ventilation, especially a vent in the damp corner to encourage some cross flow ventilation.

 

[Padraig Clarke]

Yes it is, with simple render. Was considering adding a layer of insulation boards, and re-skimming. Want to eventually use it as an office. But very cold in there right now and it's builds up condensation. Which I think is the picture of water on the floor. Floor tiles are freezing. Would the dampness/mold be caused by the coldness and lack of airflow, rather than a systemic water ingress?

 

[r896neo]

Probably mainly condensation. In an unheated space you need very good ventilation and even then it will always be damp cold air.
Its good at least that it is rendered. You need to go a fair way to make it habitable. Think battening walls with dpm behind battens, insulation board across battens, vapour barrier and plasterboard. Or build a stud wall in front of the walls. As for the floor, dpm with celotex on top and a floating chipboard floor is probably the easiest and cheapest method. Be sure to ventilate any voids you create.

 

[Padraig Clarke]

 

[Padraig Clarke]

Posted 2 more pics. This is the corner from the outside. You can see it has drainage along the side and a down pipe. The second pic is the rear of the shed. As far as I can see now only the top 1/4 is rendered on that side. The wall runs practically up against the garden boundary fence. Any other advice based on this?