Roof Soft Wash in Colleyville
The tell in Colleyville is that one side of the roof is streaked and the other side looks fine. That is not the roof wearing unevenly. That is canopy, and it is the shaded planes that stay damp long enough for algae to live.
Black streaking on a composition roof is a living organism feeding on the limestone filler in the shingle. It needs moisture to hold, which is why it colonises the elevations that don't get sun and leaves the ones that do. Under Colleyville's tree cover that line can be sharp enough to see from the street.
It comes off with chemistry at low pressure, not with pressure. Pressure on a composition roof takes granules with it, and the granules are the part doing the work. A soft wash kills the organism and it rinses and weathers off, which means the roof keeps improving for a few weeks after we leave rather than looking finished the day of.
The same canopy that streaks the roof fills the valleys and the gutters, so on most Colleyville houses these are one job rather than two. Twigs, acorns and small limbs pack a valley and hold water against the shingle, and that wet line is where the next streak starts.
Nobody walks the roof unless there's no other way to reach it. Most of what we do here is from a ladder and the ground.
What we do differently in Colleyville
- ✦Chemistry at low pressure, because pressure takes the granules off a composition roof and the granules are the protection
- ✦Shaded north and northeast planes treated as the priority, since that's where the growth actually lives
- ✦Valleys cleared of twigs, acorns and limbs in the same visit, because packed valleys hold the water that starts the next streak
- ✦Expect it to keep improving for a few weeks after, as the killed growth weathers off
Questions
Why is only one side of my roof streaked?
Because that's the side that stays damp. Algae needs moisture to hold, so it takes the elevations under canopy and skips the ones the sun dries out. Under Colleyville's tree cover the difference can be sharp enough to see from the kerb. It's not the roof ageing unevenly.
Should the gutters be done at the same time?
On most houses here, yes, and not just for the discount. The canopy that streaks the roof is the canopy packing the valleys and the gutters, and a valley holding water against the shingle is where the next streak starts. Doing one and not the other is half a job.