How do I clean render?

Question

I have a cream rendered home. My trouble is that I had a black oxide concrete driveway done and they splashed black oxide onto the render. Can anyone suggest how I can remove the black oxide.

Answer 1

Buy HCL  ( hydrochloric ) acid from builders supplies or pool shop, dilute to about  10%   in a plastic bucket (water first)  using a nylon  scrubbing brush,  acid gloves, eye protection, raincoat and respirator ... apply the diluted acid to the oxide areas, scrubbing vigorously until off,   making sure to saturate with fresh water when complete and / or in between scrubs.   Be careful not to splash too much  especially onto oneself and any vegetation should be washed thoroughly with water...   If  this still leaves oxide then repeat method....

later,  Jim    ( Builder 34yrs)