The specialist in Montreal and the North Shore for the installation of tar and gravel roofing

Tar and gravel, also referred to as built up roof, is an excellent solution for any flat roof. Although several other options are available elastomeric membrane, a built up roof provides an exceptional value. In addition to a 15-20 year life expectancy, a built up roof withstands Quebec weather conditions. Built up roofs have long proven their worthiness in residential, commercial and industrial applications.

The advantages to a built up roof

Excellent value
Great warranty
Quebec weather resistant
Superior waterproofing
Solid and durable
White roofs which reflect sunlight

Tar and gravel roof; Mastering the techniques

Installing a built up roof properly requires skilled tradesmen and specialized equipment as well as the proper tools of the trade to handle hot bitumen and layers of felt paper drenched in searing asphalt.

Roofing Felts

The underlayment membrane consists of several layers of built up asphalt felt paper saturated with hot bitumen between each layer. The felts come in rolls which measure 3 feet wide (90cm). There are essentially two types of felts; #15 asphalt saturated organic felts and fiberglass type IV ply sheets.

Asphalt or Tar

What is commonly known as tar and gravel roofing is referred to as built-up roofing in the trade. Today, coal tar is no longer used in Quebec as it is rather toxic and irritating to the eyes and skin of workers using the product. It has since been replaced by liquid asphalt.

Quantity and Temperature

Workers apply 20lbs of asphalt per 100 square feet of roof surface between layers. The final layer is three times thicker (60lbs/100sq ft.). Asphalt is heated and kept at a minimum temperature of 220 degrees Celsius during installation. It is therefore crucial for the tar kettle to be continuously and increasingly heated.


Embedded gravel is used largely to block sun rays which could temper and eventually deteriorate the asphalt. Gravel also reduces the effects of thermal expansion and contraction, especially during cold spells. The embedded gravel commonly used is made from clean and dry 1/4′ to 5/8′ crushed stone. The required quantity is 4 lbs. per square foot (200kg/square meter).

Bitumen Flashing

The roofing membrane should continue 8 inches above the roof surface where it adjoins the perimeter walls, goose necks and chimneys and should be nailed in place at the top. This particular part of the roofing membrane should be sturdier as it must resist cracking. In order to ensure such a resistance, two layers of cotton fabric are placed between each layer of organic felt, all saturated in hot asphalt. Hardened (cold) asphalt as well as fiberglass ply sheets are a poor substitute for this type of flashing.

Metal Flashing

The main purpose of metal flashing is to protect the underlayment from the sun and strikes. It does not provide a waterproof protection. Metal flashings should be made from 26 gauge galvanized steel (0.56mm) or be at least pre-painted. If aesthetics is not an issue we suggest you choose galvanized steel.

Take a look at our other products available for your flat roof

You may have heard about an elastomeric membrane which provides another viable option for flat roofs. Our experts will gladly guide you along your choices according to your needs and budget. Please click HERE if you have any questions or wish to obtain a free estimate.

R Gauthier Couvreur inc. sets the standard for roofing installation and repairs in Montreal and the North Shore. Our company is RBQ accredited, possesses civil liability coverage of 5 million dollars and a BP certification as well as a qualified and skilled work-force allowing us to earn your trust on any roofing work, be it residential or commercial. 450-654-1944

TIPS : In order to safeguard the lifespan of your tar and gravel roof, follow some of these simple steps : During the summer months remove leaves, twigs, and other debris. In winter, simply remove accumulated snow. If you’re unable to maintain the roof yourself, trust us to carry out the work.

R.Gauthier Couvreur Inc. has acquired over 30 years’ experience working tar and gravel roofs thus making us a leader in your area to execute your roofing installations. Let us perform your next roofing project.
Call 450-654-1944

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