James Desborough
Hello Dennis, Its so much difficult to repair but keeping the repair is the tricky part. Its the stages of method you need to follow. First of all you must remove all failed render keeping nice neat edges, I use an angle grinder to cut render leaving neat squares or rectangles. These neat edges give you a good basis to feather into. When you talk about metal mesh this could be a metal mesh called EML which is fastened to a previously cracked wall and then re-render adding strength to new render as so not to crack again. Or you maybe talking about metal bell cast/beading, all of which can be bought from your local builders merchant and fixed easily replacing the damged/failed section of render. It is important to add waterproofer to the first scratch coat, remembering that the maximum thickness of each coat of render should not exceed 10mm. You can prime the areas with SBR this creates a good bonding surface and can also be added to render and floor screeds to reduce shrinkage and cracking.
