Up on the roof

I took a pressure washer to my rubber roof and did some damage to several areas of the roof. Indeed, you need to be very careful of letting the nozzle get to close to the rubber fabric because it'll peel. A learning experience and spent another day on the roof patching and caulking.

Dumoldles

While I do like a clean roof, a clean roof makes for clean sides, there is no way for using harsh cleaners never mind a pressure washer.

What cleans the roof is the same stuff that cleans the sides, the Meguires auto cleaner, or similar, in the pink bottle & a soft brush. It then gets a wiping down with 303.

I have pressure washed my roofs every spring for years with a gas powered pressure washer using the yellow nozzle. No problems with it, it's enough to clean the dirt off and make is sparkly again but doesn't hurt the caulk. The only way you are going to hurt the roof/caulk is if you are irresponsible and let the tip get to close. If you hold it 18-25" away you have nothing to worry about. I sprinkle powdered laundry detergent on, wet it, scrub it with a long handled brush, and pressure wash any stubborn spots. If you are lazy skip the detergent and just use the water. The key is to not use the fine red tip, that will tear wood up and wreck everything. The yellow and white tips are much less psi and do a great job.

You can use a gas powered pressure washer, just make sure and use the black tip which has a larger opening and lower pressure, drop the pick-up wand on the pump outlet into your cleaner,when the cleaner runs out, now you are rinsing with plain water.