Cleaning the Roof Productively

Written by Tim Simpson, Quality Assurance and Quality Control Manager, Maintenance Coatings Inspector


Proper initial cleaning of your roof includes removing dirt, contaminants, and debris from existing roof surfaces. In the process of cleaning, you may also identify loose, failed areas of the roof that need additional cutting back, trimming and pre-system patchwork.

While cleaning the roof, your staff should also determine the best method of working around existing curbs, air handlers, chillers, and miscellaneous rooftop-mounted equipment. It is not unusual to see rooftop-mounted antennas, cell repeaters, DEQ air monitoring equipment, and wireless equipment telemetry now used for Building Systems Automated Management. All of these can be in your way.

With smaller heat pumps and air handlers, the equipment is frequently cribbed up on pieces of 4”x4” wood which then sits on top of existing roof systems. These may require temporarily installation of bridging cribbage beneath the equipment to allow for removal of the loose 4”x4” wood in order to properly install the new Ames Monolithic Seamless Reinforced Membrane Roof Coating System under the free-standing heat pumps. In some cases, the wood supports are embedded deeply into aged hot tar and cannot be temporarily removed to facilitate new system installation. When this happens the roofing membrane details should be carried around and completely over the embedded wood supports to monolithically seal the system under the free-standing equipment.

Other air handlers, rooftop mechanical equipment, and chillers may be sitting on permanently raised curbs that are then counter-flashed into equipment bases. These details are also flashed when Ames specified detail embedded flashing is recommended.

Regardless, after an initial cleaning of the roof exposing and temporarily removing mechanical supports will result in additional areas to wash along with further debris removal. 

It is important to promptly clean up additional dirt and debris to avoid dragging it back all over the recently cleaned roof with safety ropes, cords, spray lines, windy conditions, and foot traffic. It’s less efficient to send someone for a broom to do additional cleanup when you have a full crew standing by with Spray equipment, fabric, back rollers and other items in hand being delayed by little messes all over the roof. Do not wait until the morning of your first “Spray Day” to re-clean your roof. It slows down crew efforts, pushes you into warmer portions of the day, and is generally unnecessary. 


Click here for Chapter 6: Safety