Types of Roofs

Built-up roofing (BUR) has a long history.This "old-school" flat roof treatment involves the application of roofing felt (tar paper) and asphalt-based roofing tar, often in multiple layers. A top layer of gravel or a reflective coating is required to cut down on heat gain and improve durability. Maintenance and repair work usually call for more felt and coating layers to be applied. Over time, this adds weight to the roof and increases the mess and expense of its eventual removal. Though BUR remains an economical option, it can't compete with more modern flat roofing materials in terms of low maintenance, light weight and durability.

Modified bitumen works well on residential & small-scale commercial flat roofs. Because it comes in 3-ft.-wide rolls, modified bitumen roofing is easy to handle and apply. Basically, you roll out the material so that seams overlap. Seams can be fused with a torch or sealed with a special adhesive. The roof surface gets a reflective coating for durability and reduced heat absorption.

EPDM roofing has a good track record. Despite its exotic chemical derivation, ethylene propylene diene monomer (EPDM for short) has the look and feel of an everyday rubber inner tube. EPDM comes in large rolls and is well-suited to application over any large, flat roof surface, providing the substrate is clean and uniform. The flexible rubber material is glued to the roof substrate and to adjacent EPDM sections (Installation with mechanical fasteners is also possible). An EPDM roof can easily last 20 years with minimal maintenance, but its dark tone absorbs a tremendous amount of heat. To prolong the life of this single-ply roof and reduce cooling costs, a reflective top coating is essential. Alternatively, you can pay extra for EPDM membrane with a white top layer.

PVC roofing offers top performance for a premium price. This single-ply roofing material is made from polyvinyl chloride, the same high-performance plastic used in plumbing pipes. Like EPDM, PVC is most frequently used on larger commercial roofing jobs. Seams between PVC sheets are welded together with a specially designed heat gun. The resulting membrane is impermeable to moisture, with excellent durability. Because PVC roofing is naturally white, it has excellent heat-reflective qualities without any coating or extra treatment.

TPO roofing is a light, affordable single-ply option. TPO is short for thermo-plastic olephine, the chemical composition of this fabric-like roofing material. TPO represents a newer roofing technology that's still being refined by different manufacturers. The material comes in rolls of different sizes, making it suitable for a variety of flat roof projects. It can be installed with adhesives, mechanical fasteners or heat welding. Like EPDM and PVC roofing, TPO requires a clean, uniform substrate; it can't be installed directly over existing roofing material. Although TPO usually costs less than EPDM or PVC, it doesn't yet have the same track record of proven performance.

Spray polyurethane foam (SPF) combines roofing, flashing & insulation. Instead of tearing off an old flat roof, SPF technology enables a contractor to spray on a continuous layer of high-density foam that seals leaks, bridges gaps and forms a waterproof barrier - even around roof penetrations like vent stacks. As a bonus, the cured foam layer has good insulation value, helping to reduce heating and cooling costs. Building owners who want to avoid the mess, disruption and expense of tearing off an old flat roof often find SPF roofing their best option. Once cured, the foam is coated with a sealant that protects against ultraviolet degradation.

• Long lasting solution
• Most proven and reliable option
• Superior waterproofing
• Easy to install all temperatures
• Options for surfacing to reduce heat intake
• Reasonably priced

• Very durable and long lasting
• Environmentally friendly
• Extremely waterproof
• Easy to maintain and repair
• Heat reflective to save on energy bills
• Lower cost than many alternative materials