I use the spic and span in a bottle, I use it full strength, I put it in a spray bottle and spray it all over the roof , then I take a brush to it, then I hose it off.
I called Jayo and they said it was best to use it full strength. So that's what I do.
2015 Jay Flight 23 RB
2014 Silverado LT 1500 with a 5.3 V8 Ecotec3