Cold Applied Flat Roofing
The term “ cold applied roofing system” means a built-up roofing system assembled using a solvent-borne bituminous (liquid) adhesives with multiple plies of reinforcement.
There are many advantages that come with this type of roofing system. Chiefly among these advantages of cold application roof coatings and cement are their economical, proven performance life, and ease of use. Roof coatings and cement are generally one-component products that can be applied directly from the container. Today’s coating and cement are versatile and applicator friendly. Non-flammable products are also available.
There are 3 cold application systems:
1. Cold-Process Built-Up Roofing System
This type of roof can now be constructed a variety of ways. The predominant technique is to use heavyweight asphalt coating fiberglass “base” sheets and adhere them with solvent-borne asphalt adhesives in multiple plies. The first sheet is usually attached to the substrate (for insulation) and subsequent plies are embedded in an application of adhesive. The membrane is then covered with an aggregate surface or roof coating of choice.
Cold application process built-up roofing systems use coated or un-coated polyester reinforcements, or composite (polyester/fiberglass) reinforcements, in conjunction with either solvent-borne or waterborne adhesives. The combination of reinforcement and adhesive is typically proprietary to the system provider and compatibility should be verified with the manufacturer.
2. Modified Bitumen Adhesive Application
Membranes Modified Bitumen roofing is similar to built-up roofing in that it employs reinforcing materials coated with bitumen. The primary difference is the use of “modification” or addition of polymers to the bitumen to achieve improved characteristics. Like built-up roofing, modified bitumen roofs were typically installed using moppings of hot asphalt. An alternate approach for some types of modified bitumen was to use a propane torch to melt the back of the sheet, creating a molten adhesive in which the roll could be embedded.
Perhaps the fastest growing segment of cold-process roofing is the application of modified bitumen roofing in bituminous cold-process adhesives. For obvious safety reasons, use of cold-applied roofing has provided an attractive alternative to the use of hot asphalt or open flame. These roofs typically have a mechanically attached base sheet and one or two plies of modified bitumen membrane installed in bituminous adhesives.
3. Liquid-Applied Monolithic Membrane Systems
The third type of cold-applied roof now exists which blurs the line between roof coating and roof membrane system. That is the liquid-applied monolithic roof system. Typically made of high-tech polymeric resins such as urethanes, or bitumens which have been modified with polymers such as SEBS, these roof are applied as a liquid and may not rely on reinforcing the material, but cure to form a tough, rubber-like membrane. These types of roof are monolithic (no seams) and are typically considered self-flashing.