Vent bricks and heat loss

[NT]

I'm getting complaints about heat loss from what looks like a poor piece of house design. Its 2 stories above ground, plus basement. I'm fairly sure no dpm or dpc was used anywhere in the construction, and it has cavity walls. Damp ingress through the outer leaf of the basement wall has been dealt with by having vents from the cavity to the outside, leaving the cavities not very effective as insulation. I'm inclined to think it would be ok to block the vents, on the grounds that the inevitable damp ingress would migrate out through the outer leaf of the above ground 2 storeys. Would I be right in thinking this would work acceptably? The walls are brick.

NT

[Stewart]

I block the vents every winter to help prevent heat loss and have had no problems. Must remove them again in spring. Possible risk of radon gas coming up from ground but that depends on rock strata. When we lived in the Buchan area of Aberdeenshire it was a definite risk as rock base was granite.

[Rick]

" leaving the cavities not very effective as insulation"

ahhh ..... Cavities are not there as insulation, the function of cavities is to prevent penetrating damp without having to build 24" stone walls !

At least with standard post war building techniques.

They should be left open, as in winter you are more likely to get damp issues. Also if you have any flame devices they will be used to provide the fresh air. People have died as a result of CO poisoning by blocking cavities.

If you are unhappy with heat loss then get cavities filled with agrement approved materials.