Hi, am new to the forum and hope someone out there may be able to give some advice please. Have just removed a rotten wooden door and small window from the back of my detached garage and bricked up cavity using blocks. Rest of the wall around this is rendered in rough finish and painted so we want to try and match in as best as possible but not expecting a 'craftsmans finish'!. Can anyone advise me the correct way to render please and if its OK to render over these types of blocks? Am a bit concerned about moisture entering thru these blocks as I've read something about that elsewhere this evening. Should I use a waterproofer - it is not a very large area (average sized door and only a small window). Should I use two coats of render, allowing first to dry? Any advice will be greatly appreciated and thanks in advance for your time!