g'day all, just got a call from a client who has approx 350m2 of retaining wall (old as the hills) that he needs cleaned. There are some new sections that have been re-laid(which are no problems) and the remainder is covered in a white hard residue. To me it looks like a calcium build up, with some sections of efflorecence, but the client is adament that it's clay staining! The wall is old, and has very little drainage, so there really is no where for the excess to go except through the mortar joints. It's this reason that I feel its efflo, but it's also for this reason the client claims it's clay. A test patch with soap and hot water proved nothing as it didn't budge, and I am thinking a solution called 'noskum' which has an amount of HF in it may be the answer. Any ideas? Bare in mind I'm in Australia and dont have access to the solutions you guys have, so any base products would be much appreciated.
Brett
p.s cheers chirobob for the mitcham lead, went well
Brett
p.s cheers chirobob for the mitcham lead, went well