Coating tar and gravel roofs has long posed significant challenges for roofing contractors. So much so, that many opt simply to pass on this type of substrate.
Almost every system available calls for spudding and pressure washing, which can create very messy leaks. Many municipalities now require collection and cleaning of the asphalt exposed water.
Spudding can also expose fiberglass in the membrane which can become sponge like and trap moisture during pressure washing.
Once past the initial hurdles of spudding and washing, most application instructions are highly material and labor intensive. Let’s take a look at 3 popular systems.
Once the roof is prepared, System A begins with 2-3 coats of base coat at 2 gallons per square, followed by 2 layers of top coat for a total of 4 – 5 coating and curing cycles and 8 – 10 gallons per square.
System B is a lower cost system consisting of 2 layers of asphalt emulsion and 2 coats of a top coat. However, 1-3 weeks is required for the emulsion layers to fully cure before returning to top coat.
System C is probably the most common and the most labor-intensive system available today. It starts with a primer at 1.5 gallons per square, followed by a base coat at 3 gallons per square, into which a fabric scrim is embedded before being topped by 2 more gallons per square of base coat. Once all of that has fully cured, the system receives a white coat at 3 gallons per square.
The Ecodur system is simple, green, and extremely effective.
To begin with, spudding is optional and the choice only comes down to product coverage. Of course, a smoother substrate will yield greater coverage rates. Either way, Ecodur adheres better without pressure washing than other systems do after intense washing.
Because Ecodur has no maximum mil thickness and will cure at the same rate regardless of thickness, you can 3 course in the process of coating or do it ahead of time. Ecodur also makes an excellent filler and can even be foamed to 50% it’s normal thickness to allow for more efficient filling.
For this project in San Diego, the first step was shovel removal of about 22 tons of loose gravel.
Next, a power broom was used to further collect any remaining loose debris. At approximately 200 RPM, the power broom is far more effective compared to hand sweeping.
Because the client was getting all new ducting, the roofing contractor worked closely with the HVAC company to ensure minimal down time. In this case, only two days were required between removal and beginning reinstallation.
With the ducting removed a final sweep with power brooms was performed and the entire surface was blown with high powered leaf blowers.
Now, the substrate is ready for the Ecodur base coat applied at approximately 30-50 mils depending on the section and amount needed to completely cover. This was achieved using a squeegee and rollers.
The silicone detail and tie in for ducting were applied next to allow for the new ducting to be installed.
Finally, silicone is applied to the remaining field.
Coating a tar and gravel roof with any product is a lot of work. However, by using the Ecodur system, you can achieve better results in fewer steps reducing labor costs and liability.