Do roofs need to be cleaned?

damaged roof with black spots

So, is Roof cleaning necessary?

Does it really matter if a commercial building has a dirty roof? If the roof is flat, how would you know I the roof looks dirty, anyway?   Roof cleaning is an important and necessary step for owners and managers of commercial buildings, just as it is for a home. 

If you got a dirty roof, then you have algae, bacterial, lichen, mildew, and moss up there, eating away at the surface coating, which is why dirty roof cleaning is so important. A professional roof cleaning is much cheaper than replacing or repairing a roof, which is what will happen, eventually.

Does cleaning your roof damage it? 

Usually, professional roof cleaning is a good idea at least once every 12 months. A monthly inspection can be done by a facility or building manager, but a professional should do your roof cleaning. Why?  Because if it isn’t done right, then yes, it could damage your roof.   

When a professional roof cleaning contractor does the job, they have the right chemicals, equipment, and knowledge so that the roof is safe.  Neglecting the roof, such as not inspecting it, having maintenance and repairs done when needed, and the annual roof cleaning can be more harmful.

Why is my roof turning black?

Those black streaks and dark spots are gloeocapsa magma, which comprises dirt, grime, lichen, mildew, mold, soot, or otherwise called algae, and up close, it is blue and green. However, it has a protective dark pigment outer coating that doesn’t let the UV rays damage it. Unfortunately, it is damaging your asphalt roofing and the UV rays are baking it on, which is why annual roof cleaning is important.

Why do algae attack asphalt shingles? Algae are airborne spores that get carried away by the wind and animals that get on your roof, like birds, squirrels, etc. Once airborne, they spread quickly from the roof to roof, throughout the neighborhood. It doesn’t know if the roof is on a $20,000 house or a $100,000 house or a $1 million-dollar commercial structure.

clean roof flat and black

What causes roof stains?

Those roof stains, or commonly referred to as black streaks, and never really were a problem until twenty years ago. That is when shingle manufacturers began adding limestone for a coating on their shingles and to add weight to the shingles. There is an additive that can be added to shingles today that impede algae growth, but older asphalt roofing is still experiencing the black streaks.

Typically, those black streaks are formed on the north side of a roof. This is the side that is dark and wet, the perfect environment for algae growth. Algae grow in a blue-green color organism that forms a coating for protection against UV rays. As it decays, it turns black. Having your roof professionally cleaned once a year will minimize, even eliminate this growth from taking place.

How do you clean a stained roof?

It’s hard to justify having your roof professionally cleaned simply to remove those black stains and streaks. When you do go forward with it, you get conflicting information about the best roof cleaning process. Here, we describe three different roof cleaning processes that are used the most by professional roof contractors.

The eco-friendly method

Everyone is about being eco-friendly these days, and roof cleaning companies are all about that too. For years, the chemicals they used were toxic and damaging to the eco-system. Today, they use a low-pressure rinse system with high-grade products that are eco-friendly, with no toxic chemicals like chlorine bleach or phosphates that are known for polluting the water system and vegetation.

  • The Pros: On Average, the results are complete and instant with the algae, lichens, and other factors totally have gone while the contractor is still on site. The equipment and products they use are gentle on the roof, but tough on the black streaks.
  • The Cons: This is an expensive roof cleaning method because of the eco-friendly products.

The chlorine-bleach method

This method of roof cleaning uses chlorine bleach (sodium hypochlorite) mixed with other chemicals like TSP (trisodium phosphate). They spray it on the allowed to dry, reapply again if needed. The black streaks do not come off immediately, it usually takes a good rain to see the clean roof.

  • The Pros: A less expensive roof cleaning methods because the cost of the chemicals isn’t expensive, and the technicians do the work from the ground.
  • The Cons: The chemicals have a strong odor and the results aren’t immediately noticed, especially if there are colonies of moss and lichen present. This roof cleaning method is harmful to humans and animals if they become exposed to fluids or fumes. Landscaping can be damaged permanently because of the chemicals, as can the waterways.

The high-pressure method

A high-pressure roof cleaning method has been used by contractors for years.

  • The Pros: There aren’t any.
  • The Cons: High-pressure roof cleaning method damaged shingles, but it does not remove the organisms that cause the black streaks effectively. The algae return because the high-pressure power roof cleaning method leaves the root system of the algae behind.

A regular routine of roof inspection and roof cleaning is needed to maintain a healthy roof, which protects the largest investment you’ll ever make – your business.  By reviewing the pros and cons we’ve shared with you that the three main roof cleaning methods have, this should help you choose the right roof cleaning contractor. Call 513-342-8544 today for commercial roof washing in Cincinnati, OH.