We often get asked “Should I pressure wash my roof?”especially from homeowners looking for ways to remove roof moss or debris. It’s also a topic that sees an abundance of differing opinions among roofing contractors and pressure washing companies.
While we applaud your efforts in trying to keep your roof clean, here at the Roofing Annex, we do not recommend pressure washer to clean your roof. We have seen many a roof damaged from this type of cleaning, plus you could void your roof warranty.
Roof Power Washing Variables
A lot of variables are involved when cleaning a roof with a power washer. For starters, if the output pressure of the machine is not regulated properly, the high water pressure can significantly damage roofing materials. Then there’s nozzle size. If the proper nozzle is not used, the output spray could be too harsh for the roofing.
Another consideration is roof penetrations, such as skylights, vents, flashing etc., where high pressured water could compromise the sealants and enter the home. Water temperature is also a concern. If the temperature of the water is too hot, it could damage roofing components. Lastly, if the angle of both the spray directed at the roof and the deflection spray are not correct, serious roof damage can occur.
Problems Created By Pressure Washing a Roof
A high water pressure system can create all sorts of roofing problems. Because roofing materials are not designed to withstand such a high level of water pressure and its abrasive action, using a pressure washer on a roof can:
- Hasten the degradation of roofing materials at least three times faster than their life expectancy.
- Damage shingles by uplifting them.
- Break the adhesive bond between shingles.
- Damage the fabric of the roofing material.
- Completely strip and wash away the protective granules on a shingle.
- Cause cracks in slate, tiles and cedar shake roofing.
- Actually spread moss and other fungus on a small area of your roof across your entire roofing system.
All these types of roofing damage can compromise the structure of your roof and lead to water leaks in the interior of your home.
Other Roof Cleaning Options
There are numerous other ways to clean a roof, several of which effectively remove moss and other debris. Some options include:
- Cleaning a roof using a high volume, low pressure system. This is also known as soft washing your roof.
- Using a soft broom or brush.
- Using a garden blower to remove debris.
- Applying a roof treatment that fights moss, mildew, algae, or other fungus.
At the Roofing Annex, we just don’t install roofs, we service them, too, providing routine roof maintenance and care. Contact us anytime you need advice or assistance with caring for your roof. We can advise you on the best method for your roof type, offer you various options and prices for comparison, and apply a roof treatment that addresses your roofing problem. Think of us as your all-access roofing contractor, with expertise in roofing and roof treatments!