Flat Roofing

If flat roofing systems are properly installed, they can last between 10 and 30 years – but if they are poorly constructed or simply neglected, problems will start almost immediately.

Needless to say, leaks are among the most common of those problems. The flashings around roof penetrations like chimneys are particularly vulnerable to leaking, as are vents, pipes, antennae and skylights.

Did you know?

It may sound strange, but even a flat roof needs to be properly sloped. Even a gentle 2% slope is enough to keep water from pooling on the roof. If water stands on your roof for more than 48 hours after a rainfall, it could damage your roof.

If your flat roof needs repairs, consider that a good time to insulate that area at the same time. Because flat roofed buildings don’t have attics, the need for insulation is often overlooked. Juffs can help you with your flat roof repairs and your insulation needs at the same time.

Keeping roof drains free of leaves and other debris is especially important, because clogged drains cause water to “pond” on the roof. This extra “dead load” on your roof can lead to disaster.

The product you choose must provide positive drainage. At Juffs Roofing, we recommend the sloped or tapered insulation manufactured by POSI-SLOPE:

The Concept

POSI-SLOPE is a factory pre-designed tapered roof insulation and drainage system. It is designed to add thermal insulation to the roof system while eliminating water ponding on new and existing roofs. (Minimizing standing water adds substantially to the longevity of a roof.)

The System

POSI-SLOPE is a modular system manufactured from various insulation materials; the rectangular shaped modules are tapered smooth and true to permit full adhesion to roof insulation or other roof substrates. In addition, the POSI-SLOPE Enterprises system provides full value with factory mitred pieces and is packaged for ease of installation.


Numerous sources of insulation materials enable POSI-SLOPE ENTERPRISES to provide impartial advice and multiple solutions for any building design or roof assembly. POSI-SLOPE is compatible with virtually all types of roofing membranes including Single-Ply, Modified Bitumen and Built-Up Roofing.


It is available in common slopes of 1%, 1.5%, 2%, 4% plus an infinite range of slopes customized to satisfy most drainage or thermal requirements. POSI-SLOPE is a very cost-effective way to drain and insulate an existing roof, as well as complementing structural roof slope in new construction.

POSI-SLOPE Enterprises adapts to all roof conditions and budgets including full taper systems, correction in deck deflections, and complementary components such as backslope, crickets, and sumps.

With computerized drafting and estimation, POSI-SLOPE Enterprises can solve roof drainage and insulation problems via the Internet. R-value reports and budget prices are also included.

For ease of installation, POSI-SLOPE Enterprises provides a clear CAD shop drawing, colour-coded packaging by roof area and delineation of all full or mitered panels. All material is packaged by roof area, and pallets are poly-bagged and labeled with corresponding colour coded packing information.

There are four major types of flat roofing:

  • DecTec Flat Roofing

DecTec is a “walkable” PVC roof membrane. As its name implies, it is used on outdoor decks to help them withstand heavy pedestrian traffic.

Now, you may not be planning to spend a lot of time entertaining or relaxing on your roof — but DecTec’s superior strength, along with its ability to resist UV, snow, rain and mildew damage, make it a great choice for almost any roof converting into an exterior living space where you can enjoy the view.

DecTec’s 100% expansion factor lets it expand and shrink in our ever-changing climate.

DecTec is also attractive and low maintenance, and comes with a full 10-year limited warranty.

  • EPDM Flat Roofing

Synthetic rubber EPDM (Ethylene Propylene Diene Monomer) single-ply flat roofing is low cost, low maintenance and easy to apply.

When properly installed, EPDM can have a lifespan of between 15 to 25 years.

The latest versions of EPDM have a polyester fleece backing that keeps it from shrinking, letting it move with your roof through seasonal weather changes.

It also offers high fire and heat resistance.

  • Modified Bitumen Roofing

This type of asphalt-based roofing has been around for the last hundred years. It is considered superior to other materials like tar and gravel, and is easy to repair (without the fumes you get from tar!)

Modified bitumen roofing is extremely waterproof. It can last 30 years if installed and maintained properly.

A modified bitumen roof needs repair if you notice deboned seams, blisters, wrinkles or an “alligator skin” surface.

  • PVC and TPO

The most common thermoplastic roof membranes are made from either PVC (polyvinyl chloride) or TPO (thermoplastic olefin).

PVC system installations are quick, clean and cost effective. PVC is designed to withstand various temperatures and weather conditions, and provide a watertight seal thanks to their welded seams.

TPO is the newer of the two types. TPO is considered reliable and affordable, as well as ecologically friendly and waterproof.

Choosing the right insulation for a flat roof is especially important. Along with adding positive drainage to your roof system, tapered insulation is designed to create a gentle slope on a flat roof. This slope minimizes the formation of pools of standing water that can cause damage to your roof. Tapered insulation is available in a variety of different slopes to satisfy most drainage and thermal requirements.

Completed Flat Roof With Sloped Insulation. Picture taken 20 minutes after a heavy rain.

Sloped Insulation

Juffs Roofing is here to help you! Ask us about what kind of flat roofing system is right for you, and how we can fix any problems you are having with your modified bitumen, DecTec, PVC, TPO or EPDM roof.