The quality of the roof you have installed, including both the quality of materials used and the skill and experience of the crew doing the work, will have a big impact on both performance and length of roof service.
As read in the Roofing System Comparison section of this website, built-up roofs (BUR) of tar or tar and gravel, although sometimes less expensive in the beginning, must be torn off and replaced when they reach the end of their life. Additionally, because they absorb the sun's energy, they can add considerably to a building's cooling costs.
Single-ply systems offer some improvements, because they are usually white or light colored to reflect the sun. The problem is that the material is typically mechanically attached, thousands of additional screw holes are introduced in the roof.
Spray-applied foam systems or spray foam offer energy efficiency, versatility over a variety of surfaces, and unparalleled integrity to protect the building from future water leaks. They can also be "renewed" to original specifications much less expensively than re-roofing using other materials.
Three basic coating chemistries are available, acrylic, silicone and polyurethane. While acrylic and silicone are somewhat less expensive, the difference is in the percentage of solids by volume, resistance to puncture (tensile strength), resistance to degradation and resistance to abrasion.
In general, acrylic coatings are more resistant to puncture and less resistant to UV degradation; silicone coatings tend to last longer, but have a lower tensile strength. Polyurethane coatings are more expensive but offer the best protection and longest life span. In a consultation, we will pick the best coating to suit your roofing and financial needs.
Installation standards
Tillotson Enterprises utilizes the following installation standards for spray foam roofs. Compare these standards with competitive bids.
Foam compressive strength of 2.7-3.0 lbs. per cubic foot
Closed-cell not open-celled foam
Minimum pass thickness of ½ inch
Minimum total thickness over smooth surface of one inch
Minimum total thickness over irregular surface of 1-½ inches
Wood decking to be exterior grade and not less than 15/32”
Flat structural metal decks not less the 22 gauge
Pitched metal building roof panel not less than 29 gauge
Acceptable surface texture to be as smooth as possible
Tents and windscreens should be used to minimize overspray in windy conditions.
