Modified bitumen is a rolled rubber roofing system, created and originated in Europe in the early 1970s. It is made of fiberglass or a fiberglass/polyester combination base sheet saturated with bitumen asphalt. Coloured granular is coated on the top side of the base sheet to shield t it from powerful UV rays. The benefits to modified bitumen in comparison to the tar and gravel (built up) roofing system are that it is very compact and also requires minimal equipment to install. Keating Roofing & Exterior Contractors have attended many modified bitumen application courses and carry the highest level of industry certification.
Keating Roofing & Exterior Contractors and other Toronto roofing professionals began to use modified bitumen when it was introduced in North America in the early 1980s. At that time the Ontario building code stated that flat roofs must have a positive roof slope of 1/4″ for every 4′ run towards drains or draining edges. However many Toronto area homes were constructed with completely flat roofs using built up roofing systems which forgives ponding water on the surface. In the past some roof drains were actually raised deliberately to keep the roof cool by creating ponding. Manufacturer expectations with the modified bitumen roofing system is that there is to be no ponding or residual water 72 hours after any rainfall or all warranties will be invalid.
Leading the way in the Toronto roofing industry, our goal at Keating Roofing & Exteriors is to correct the historic flat roof architecture by designing a roof system within your budget that exceeds the requirements of the manufacturer and achieves your desired needs specific to your home.
Tar and Gravel
The other reliable flat roofing alternative installed by Keating Roofing and Exterior Contractors is the Tar and gravel (built-up) roofing system. Built-up roof membranes, made up of layers of polyester, fiberglass or organic felt reinforcements, are laminated together with bitumen (asphalt or coal tar). Each material plays an important role in achieving a superior, long lasting roofing system. It is not uncommon for a properly done built up roof to last 50 to 70 years with some now performing for over a century.
Bitumen, made from natural and petroleum asphalts as well as coal tar pitch, is the adhesive and waterproofing component of the built-up roofing system.
Felts, organic (paper, rag, cotton) or inorganic (fiberglass, polyester) provide strength and stability. Built-in roofing felts such as saturated, coated and mineral surfaced, are available in sheet form.
Surfacing protects bitumen from drastic changes in elements such as sun radiation, wind and rain. Mineral aggregate like pea gravel or crushed gravel is the most common type of roof surfacing.
Call Keating Roofing & Exterior Contractors at 905-270-4100 to find out if a modified bitumen flat roof or tar and gravel (built-up) roofing system is the best choice for your home.