Regular roof inspection and maintenance is key to extending roof life. These chores help prevent issues from becoming major problems by catching them before they happen. One component of maintenance for flat or low-sloped roofs is keeping them free of debris, which can create problems with drains clogging, ponding water, or physical damage.
Another way to keep the roof clean (after removing debris and clutter) is actually washing the roof surface. All low sloped roofing membranes accumulate dirt over the life of the roof from pollutants and dust. Flat roofs also tend to have areas where water collects and when the water drains or evaporates, it leaves behind dirt that can promote algae buildup and stains.
There are a few reasons why you might want to wash the roof. First, washing removes the algae and other contaminants that could reduce the lifespan of the roof. Also, if your roof is visible from adjacent buildings or the road, a dirty surface will detract from its aesthetic appearance. Perhaps the most important reason is to preserve the roof’s reflectivity, which is very important when it comes to your building’s energy savings. This is especially true in dry, dusty areas of the country (the southwest in particular), which benefit the most from roof reflectivity and which can collect a lot of airborne dirt. In these locations, the cost of periodic roof washing might be much less than the money building owners would save on energy with a roof whose high reflectivity is maintained.
Most single-ply roofing manufacturers have guidelines for washing the roof, and the recommended tools are soft bristle brooms, mops, squeegees and low-pressure hoses. A non-abrasive cleaning solution may include Spic and Span® or tri-sodium phosphate that’s applied to the membrane after it’s been wetted down. Care must be taken to use equipment that won’t damage the roof surface. Anything with a sharp edge is a problem, as are pressure washers.
Before doing any cleaning, check the roof for missing components, loose membrane seams, cracks and other problems that might indicate a compromise in watertight integrity.
Cleaning the roof is a simple task that could possibly be done by your own building maintenance staff. However, to ensure that it’s done properly so that your roof keeps performing at its best, it might be best to hire a professional.