Power Washing and Roof Cleaning Forum

Michael Wedge · Approved Exterior Cleaner

Road Grime

Diamond Roof Cleaning · Approved Exterior Cleaner

Its more than likely just algae. If the mix doesn't work as it should then mix some sodium hydroxide in there. Only use 16 ounces per 50 gallons. I don't think your going to need it though.

-- Edited by Diamond roof Cleaning on Monday 2nd of March 2015 01:24:13 AM

Maverick Contracting · Approved Exterior Cleaner

mikes right, sodium hydroxide is a degreaser but will also break down the asphalt shingle (obvliosly perto based) so try basic mix first.

Ed Thompson · Approved Exterior Cleaner

Hello Mr Wedge. A picture would help. Most here could pin it down by looking.

Jeff Thompson · Approved Exterior Cleaner

Yep, sodium hydroxide does break down the shingle. One of my very first jobs I used to much, thick black goo running down the drive was the result. Was bracing myself for the phone call from the home owner but it never came. Also never used sodium hydroxide again. I'm sure with what I know now it would be a welcome addition to the arsenal, but just be aware it could cause some issues if not used properly.