Damp help

[sihackett29]

I have bought (1 year ago) an old house in NW England - it’s 300 years old and sandstone.
It’s been empty for a year but in the past 6 months has developed damp in two main locations:
1. The internal walls the back onto one of the blocked up chimneys are damp in all three floors (ground first and second). Chimney is bricked up internally and the pots mortared shut. There are air bricks externally on all three floors.

2. There is a significant amount of damp on the active chimney walls (not blocked up but not been used for a year).

Is anyone able to provide any guidance on how to be to bottom of things? I presume in the blocked off chimney that although it’s mortared over, the air bricks would be enough to ventilate it?

 

[^woody^]

Penetrating damp, or condensation damp from being unoccupied?

Determine the reasons, then the cause before thinking about solutions.

 

[JohnD]

Chimneys need to be ventilated top and bottom. There may be several flues in a stack. Start with that.

the top of the chimney may also have rain penetration.

Unused chimneys can be demolished below roof level and the roof reinstated over them, which reduces the risk of future damp, and the cost of future maintenance

Have a look at the bricked up fireplaces. They may be choked with damp builders rubble, which needs to be shovelled out.

 

[tell80]

OP,
Ignore the nonsense suggestion that you demolish a chimney stack in a 300 yr old house.

Why not post pics of all the damp locations - all active or blocked fireplaces - the stack(s) & mortared up pots - the air bricks on all three levels?

 

[jeds]

I presume in the blocked off chimney that although it’s mortared over, the air bricks would be enough to ventilate it?

As above, redundant chimney flus must be ventilated from each fireplace to the top of the stack. Doing so may or may not actually solve all of your dampness but this needs to be done anyway so is a good place to start. Whilst you have access to the flus it is also worth checking that they were thoroughly cleaned before they were blocked up.

 

[Nige F]

OP,
Ignore the nonsense suggestion

Why not post pics

Usual cut and paste from tell