hi, we have been asked to clean algae, black marks off a 40,000 square foot factory unit, we have done test patches with a wfp system (hot) and cleans up ok, on the front of the building there seems up top blackish rust marks where the fabrication joins together which has dripped down the front of the building, these are proving slightly more difficult to remove, would g101 be any good on this..? one operative applying a mixture with a brush., another operative following on with hot wfp, on the roof there are around 80 skylights that have gone dark brown in colour, they want these cleaned and tell me they are some kind of fibre glass construction, any help or guidance must appreciated as well as any hints on pricing this correctly, thanks in advance
Graham