Conestoga Roofing specializes in industrial and commercial flat roofing systems. We believe it's important that our customers are educated on their roofing needs as the investment in commercial flat roofing systems are significant. Our expert estimators, project managers and roofing crews will gladly answer any questions you may have concerning your roofing project. We've included information from the National Roofing Contractors Association on the most common flat roofing systems for industrial & commercial buildings to help you make your decision. If you have more questions, please contact us.
Types of Flat Roofing Systems
- BUR
- Single Ply Membrane
- EPDM
- TPO & PVC
- Modified Bitumen
- Metal Sloped Roofing
Built Up Roofing - BUR
These roof systems are sometimes referred to as "tar and gravel roofs" (although we don't use actually use tar as it's a carcingenic) and asphalt BUR is the most common type of flat roof at this time. Conestoga Roofing is expert at installing and repairing BUR roofing systems.
Built Up Roofing System BUR systems generally are composed of alternating layers of bitumen and reinforcing fabrics that create a finished membrane. The number of plies in a cross section is the number of plies on a roof: The term "four plies" denotes a four ply roof membrane construction. Sometimes, a base sheet, used as the bottom most ply, is mechanically fastened. Built up roofs generally are considered to be fully adhered if applied directly to roof decks or insulation. The reinforcing fabrics also are called roofing felts or ply sheets.Single-Ply Membranes
Single-ply membranes are factory-manufactured sheet membranes. They generally are categorized as either thermoset (EDPM) or thermoplastic (TPO or PVC). Thermoplastic materials can be repeatedly softened when heated and hardened when cooled. Thermoset materials solidify, or "set," irreversibly after heating. Single ply membranes commonly are referred to by their chemical acronyms, such as ethylene propylene diene monomer (EPDM).Single-ply sheet membranes are produced using one of three manufacturing processes: calendering, extruding or spread coating. The membranes may contain reinforcement layers. Common reinforcements for single ply membranes include polyester fabrics or scrims, glass fibre, or a felt or fleece backing.EPDM A Single-Ply Membrane
Ethylene Propylene Diene Monomer (EDPM) roofing is an efficient rubber roof style used on low-slope roofing surfaces. It is a synthetic rubber most commonly used in single-ply roofing because it is readily available and relatively simple to apply. It is also called Single Ply Membrane and it is one of the common types of low-slope roofing. It's been in use on roofs in the Canada since the 1960’s. When properly applied, it has a life cycle of 15 to 25 years. It is great for preventing leaks and is often installed for roofs that have problems with weathering, failing joints, and inflexibility. It is relatively inexpensive as well as simple to install as compared to BUR. Compared to conventional built-up roofs, it is also much cleaner and doesn’t emit the odors and fumes that are often associated with built up roofing systems. (Although Conestoga Roofing uses an "odourless kettle" when it comes to applying BUR.) Vulcanized EPDM is the most common type of EPDM roofing system. Non-vulcanized EPDM is typically used for flashing purposes.
A fully adhered EPDM roofing system. There are three methods of applying EPDM:- Fully adhered EPDM uses water-based or solvent-based adhesives to adhere the EPDM rubber to the substrate.
- Mechanically fastened EPDM is attached to the substrate by manufacturer-approved mechanical methodology.
TPO & PVC
Another example of a Single-Ply Membrane is the thermoplastic TPO or PVC roofing system. These membranes can be repeatedly softened by heating or hardened when cooled. Because of the materials' chemical nature, thermoplastic membranes typically are seamed by heat welding with hot air or solvent welding.
The most common thermoplastic roof membranes are PVC and TPO. The following provides general descriptions of these two systems .Modified Bitumen
Polymer-modified roof membranes are composed of reinforcing fabrics that serve as carriers for the hot polymer-modified bitumen as it is manufactured into a roll material. MB roof system membranes are composed of multiple layers, much like BUR membranes. MB roof systems typically are installed as a two-ply system and almost always are fully adhered.There are two types of MB roofing membranes:- SBS polymer-modified bitumen membranes commonly are installed in hot moppings of asphalt (similar to BUR systems) or cold adhesive. Some SBS modified membranes are self adhering; that is, they contain an adhesive backing.
- APP polymer-modified bitumen membranes typically are heat-welded or torch-applied.