Flat Roofing FAQ

What are the most common causes of roof leaks?

The most common causes of roof leaks are

  1. Old/worn out (time, weathering, mechanical abrasion, foot traffic, air pollution)
  2. Mechanically damaged (wind, falling objects such as tree branches and hail)
  3. Patched (weak areas from previous repairs)
  4. Multiple layers (new membranes added over old membranes)
  5. Blisters (air/water trapped between roof sheathing and membrane or in the asphalt)
  6. Alligatoring (asphalt brittles due to sun damage)
  7. Gravel erosion (wind and water running across a roof)
  8. Ridging and fishmouths (installation problems related to asphalt, moisture, structure, expansion or slipping of felts)
  9. Membrane movement/splitting (membrane shrinkage through cold weather cycles)
  10. Ponding/Vegetation (poor design/no slopes, no drains, blockage of drains or an inadequate number of drains)
  11. Debris or storage on the roof (construction activity and material storage)
  12. Exposed felts (inadequate top pour of asphalt, felts not laid flat, failure to adhere felt at edge.

What is flat roofing?

Flat roofs are horizontal. They have very little slope when compared to roofs on a home or residential building. Flat roofs are  commonly found on commercial and industrial buildings around the world.

What type of roofing services do we offer?

We offer exceptional flat roofing services for commercial & industrial properties in Toronto and the GTA including 24/7 Emergency services.

What is our warranty policy?

Gentech Roofing offers 5 year and 10 year edge to edge warranty services. For more detailed information, please contact us.

What is our health and safety procedures?

The safety of our customers and our employees is of the highest importance. We are fully compliant with the WSIB and are good standing. In addition to that, our employees are up to date with all mandated M.O.L training, which includes the Working at Heights and Worker Health and Safety Awareness in 4 steps as well as our own in house training, which includes; Orientation, PPE, H & S policies, WHIMIS, Propane Safety, Fire Extinguisher, Basic first Aid, CPR for supervisors and lead hands, fall protection, Emergency response, and many other topics. This ensures that every Gentech Roofing employee carries out their duties professionally, respectfully, and most importantly, safely.

What is TPO, PVC, EPDM Roofing?

TPO – (Thermoplastic Olefin) Advanced rubber roofing made by laminating layers of polymer material together. This results in a membrane that is durable, easy to install and usually costs less than PVC roofing materials for flat roofs.

PVC – (Polyvinyl Chloride) Also known as thermoplastic roofing has been used since the early 1960’s. PVC is a flexible plastic sheet that has the same feel as vinyl swimming pool liners and inflatable water toys. It may be secured to the roof deck with contact cement, mechanical fasteners or securement strips.

EPDM – (Ethylene Propylene Diene Monomer) A durable, single-ply roof system often called a rubber roof, is durable, lightweight, cost-effective and best suited for colder climates due to its dark color. EPDM is made from ingredients derived from oil and natural gas, which can be fully adhered, mechanically attached or ballasted with seams sealed using a liquid adhesive or specialty tape.

What is Built-up Roofing (B.U.R)?

The roofing felts are typically four plies composed of layers of reinforcement such as fiberglass or polyester felts, with each ply being embedded in a full bed of hot asphalt/bitumen. The bitumen provides the adhesive and waterproofing membrane while the felts provide the membrane reinforcement and the surfacing. The roofing membrane is fully adhered to the underlayment, which typically consists of a vapour barrier, Poly ISO insulation and/or Fiberboard insulation, and four layers of perforated felt #15 and asphalt laminated together. Finally, the gravel ballast protects the bitumen from deteriorating influences of the ultra-violet light caused by the sun, and erosion due to wind, snow, hail and rain. This roofing system is resistant to moisture, punctures, tears and weathering.


What is 2ply S.B.S Modified Bitumen Roofing?

These systems are composite sheet membranes which have thermoplastic and elastomeric properties which generally consist of bitumen and reinforcing surface materials. These are three common installation methods; torched-on (thermo-fused), mopped-in and peel and stick (self-adhering). The roofing membrane is fully adhered to the underlayment, which typically consists of a vapour barrier, Poly ISO insulation and/or fiberboard insulation, one layer of base sheet and one layer of cap sheet. The cap sheet has a granular surface (similar to asphalt shingles) to protect the bitumen from the deteriorating influences of the ultra-violet light caused by sun, snow, hail, rain and erosion due to wind.