I have approx 25 mtrs to cover.The walls are of brick construction ( 1936 ) and in sound condition. A doorway and window have been blocked up using celcon blocks. I intended to rend-aid the blockwork and when ready, render the lot with OCR. However,the guy at Weber says i should mesh where the block/brick meet and rend-aid everything to make sure. Is this to cover their arses as the brickwork is sound or simply good advice ?