by codsallian »
Sun Jan 13, 2008 10:10 pm
I have a similar situaton with our kitchen extension although the flat roof is covering the top of the cavity. I believe the normal way to fill cavities is by pumping in foam or strands of mineral wool, so your best bet may be to contact one of the companies who do that. I think the risk of dampness across the cavity depends on the exposure of the wall to wet weather. i.e. is it facing southwesterly or high up a hill for example