Damp upstairs

[partin77]

Hi

I have a problem with damp in my 120 y/o stone built terraced house. I have black mould on the walls on both my front and back rooms upstairs. I have painted over this before with a waterproof paint but the problem still persists can anyone offer some advice?

 

[SUPERSLASHER]

Without seeing it i would say that the pointing is open and letting in water. Have a look outside at the pointing and see if there is any voids in it. If you do find voids you will have to cut them back 20 to25mm and repoint them. The mix for pointing stonework is 2 washed sand 2 washed sharp sand 1 cement and half lime with some pva added. Dont make the mix to wet as it will smear the stone. Before you start to repoint wash down the walls as this will get rid of the dust. If the holes in the pointing are deep dont fill out in one go build it up in layers.

 

[davebelushi]

Sounds like a condensation problem to me as opposed to a penetrating dampness issue.

You could look at increasing the ventilation by speaking to -

http://www.timberwise.co.uk/pages/Air-Quality-Solutions.php

or someone similar...

Or increasing the temperature of the internal wall surface to reduce the risk of condensation.

D

 

[^woody^]

Black mould is indicative of condensation issues.

But you need to determine if its a straightforward case of moist air condensing on the cold wall, or if there is some penetrating dampness from the outside which is then lowering the wall temperature.

Either way no amount of waterproof paint on the inside will stop this.

Check the external wall and follow the FAQ for dealing with condensation

 

[JohnD]

//www.diynot.com/wiki/building:condensation_in_houses