Today I had a survey for cavity wall insulation and after reading various posts about ensuring the airbricks are maintained - I'm confused.
The 'surveyor' said the installers would check if the airbricks are sleeved and if not, install a brush in the cavity around the air brick to maintain air flow. Surely this means removing the airbrick, in which case it must be easier to replace with a sleeved version.
But in any case this wouldn't work in my house as the external airbrick is one course of bricks lower than the internal air brick (or rather a missing brick).
Any ideas?