Novice question - am having professional building work done, and noticed that cavity tends to be larger at top of wall than bottom (i.e. the blockwork leans in slightly).
Is this a building technique, and if so, what for ?
Or, er is it wrong, and the brick and block walls should be perfectly parallel?
How much variation in gap would you expect to find in different parts of same wall - 1cm, 2cm, 3cm, more ?
thanks for any assistance