Roof Cleaning in Farmers Branch and Across Dallas

Most of the time, when somebody calls us about a dirty looking roof in Dallas or Farmers Branch, it is not dirt at all. Those dark streaks running down from the ridge are a cyanobacteria, and the Asphalt Roofing Manufacturers Association names Gloeocapsa magma as the most likely culprit behind roof discoloration that gets mistaken for soot, dirt, or mold.¹

Here is the part most homeowners have never heard. The organism is feeding on the roof. Manufacturers use crushed limestone as filler in asphalt shingles, and research on Gloeocapsa magma identifies that limestone as the nutrient source it needs to survive.² So the staining is not something that landed on the shingle. It is something living off the shingle, which is why a plain rinse never keeps it away for long.

North Texas gives it what it wants, too. The National Weather Service classifies Dallas-Fort Worth as a humid subtropical climate with hot summers,³ and warm humid conditions are where this growth takes hold fastest.

Moss is a different animal. That is usually growing on the north-facing slope, or under a big oak that keeps that section shaded most of the day. Less sun, more moisture, moss moves right in. And moss does more than stain, because it can lift or curl the leading edges of the shingles, which raises the odds of a blow-off the next time the wind picks up.⁴

So we look first and figure out whether we are dealing with algae, moss, or plain dirt, then pick a method that matches. If you look really closely at the streaks, you will usually see they follow the water path off the ridge, and that is the growth spreading with runoff rather than random staining.

So here is the thing nobody tells you before they hop up on your roof with a pressure washer, and it is the reason we get called out to look at jobs other companies started. Asphalt shingles are not concrete. A driveway can take high pressure all day, but ARMA's guidance is to never use a pressure washer on an asphalt shingle roof, because it causes granule loss and very likely premature failure of the roof system.⁴ Those granules are what shield the shingle from UV, so once they are gone, that spot ages faster than the rest of the roof and you can pick it out from the street.

The other option would be soft washing, and that is what we use on shingle roofs. Low pressure, a cleaning solution that breaks the growth down at the root, time to let it work, then a gentle rinse. It has to be low pressure, can't be forced.

We see a lot of homes around Valley View Lane and along the Rawhide Creek corridor with roofs pushing 15 to 20 years, and those older shingles are already brittle from the sun. Hit those with a power washer and you are not cleaning the roof, you are shortening what is left of its life. Soft washing gets you the same clean without stripping anything.

Now, here is what to ask before you hire anybody, and it is a fair question to put to us too. Ask whether they are soft washing or running straight pressure on the shingles. Once those granules come off, they do not come back. That is kinda just one thing that separates a careful crew from one that is spraying and going.

Worth knowing if you are already close to a replacement: some shingles are manufactured with copper-bearing granules that fight algae growth over time. GAF builds this into their StainGuard Plus line and backs it with a 25-year limited warranty against blue-green algae discoloration.⁵ It will not help a roof you already own, but it is worth raising when you are picking shingles for the next one. We can walk you through the options on a roof replacement when the time comes.

Not every roof that looks rough needs a cleaning. Sometimes what you are seeing is algae, and a soft wash handles it fine. Other times what you are seeing is the roof telling you it is near the end, and washing it will not fix that.

Black streaks that sit on top of the shingle, that is usually algae, and that is a cleaning job. Bald spots where the granules are gone and the black mat underneath is showing, that is not dirt, that is the shingle itself wearing out.

• •Shingles curling at the edges, or shedding granules in handfuls when you run a hand across them
• •Soft, spongy spots underfoot, which usually means the decking has taken on water
• •Cracked, lifted, or missing shingles from wind or hail, not just discoloration
• •Daylight visible through the attic boards, which is a repair matter rather than a washing matter

We won't run water on a roof that is already shedding granules. It has to hold up, can't be brittle. Spraying a worn-out roof just knocks loose what little protection is left, and now you have a bigger problem than streaks.

So if you call us out and we get up there and see cracked shingles or soft decking, we are going to tell you that first. Cleaning a roof that needs repair is money spent in the wrong place. We would rather start with a roof inspection and walk you through what we are seeing, then tell you plainly whether this is a wash or whether it is time to talk about roof repair.

Before we ever get on the roof, we walk the property. We are checking pitch, looking at where the growth has built up, and figuring out which slopes need more attention. On a lot of the older ranch homes around Farmers Branch, you have got mature trees hanging over one side of the roof, and that is where the black streaks show up worst. That side gets treated a little heavier.

You do not need to do much to get ready. Move patio furniture or grills away from the drip line, and if you have got a car parked close to the house, pull it out for the morning. That is really it.

• •We inspect the roof and mark problem areas before any water or solution goes down.
• •We apply a low-pressure soft wash treatment made to break down algae and moss without stripping granules.
• •We let it dwell so it actually kills the growth rather than just rinsing the color off, then rinse from the ridge down with low pressure.⁴
• •We cover landscaping and rinse any siding that caught overspray, so nothing dries streaky.
• •We do a final walk of the yard and roofline with you before we pack up.

Now, the whole thing usually runs a few hours depending on the size of the roof and how bad the growth is. And you will notice something right away, because most homeowners are surprised how much lighter the shingles look once the streaking is gone.

We don't leave until the yard is clear of debris and the gutters are running clean.