DIY Doctor UK DIY Forums

Afternoon all,

I have what I believe to be penetrating damp. Our property is a two bed terrace. Edwardian build, circa 1902. The only location of the damp is the top of the walls either side of the from window, ground floor only. There are some small rendering cracks outside of the house but these aren’t major. Could this be from the render cracks?

Hi anthony1333,
The most likely cause is the hairline cracks in the rendering. They will wick moisture into the wall and the only way out is towards the inside.
Damp the cracks, fill with flexible filler and paint over, you will probably have to repeat this process regularly as your wall moves.
In about 6 months time you will know whether this was the problem, if not look for an issue with your upvc windows, assuming that is what they are.
Regards S

Thanks for your advice! What would be the best filler to use for this?

Hi anthony1333,
Use a flexible decorators filler for internal or external use. Not silicone sealant.
Regards S

Thanks mate much appreciated