Damp patch on back of kitchen cabinet in front of air brick

[t1ger]

We just had our cavity wall insulation done. I noticed a new looking damp patch at the back of a kitchen cabinet that seems to line up exactly with the air brick. What is the best thing to do to prevent the damp? Put a vent in the back of the cupboard in line with the air brick?

Thanks

 

[dextrous]

Assuming that the airbrick is above the damp proof course, it no longer serves its purpose of ventilating the cavity. Therefore, you could remove it and replace with bricks, or, as they did in my house, squirt some silicon into the holes!

At present, it's providing a relative cold spot (insulation or not) which is most likely causing internal condensation.