Types of Roof Construction
There are a variety of roof membranes and methods available for new construction or roof
replacement. Maritime Group Corp. is fully qualified to meet all your roofing requirements no matter
what the existing conditions, or preferred roofing system. The most common roof systems and
their respective advantages & disadvantages are described below.
| Roof Type
|
Description
|
Advantages
|
Disadvantages
|
| Built-Up-Roofing (BUR)
|
Traditional ‘tar & gravel’ roof, consisting of multiple plies of roofing felts mopped in hot bitumen, with bitumen coated surface imbedded with gravel.
|
Durable, low cost. Multiple plies provide redundant layers of protection Ease of application, maintenance and repair.
~ 15 to 20 years lifespan, up to 30 years with enhancements/maintenance
|
Can be messy and smelly during application of asphalt
Pricing can fluctuate due to the costs of petroleum products and disposal costs (for re-roofing)
|
| Single-ply membrane (EPDM, PVC, TPO)
|
Single-ply roof membrane that can be loose-laid & ballasted, mechanically attached, or fully adhered. Seams can be glued, taped, or hot-air welded. The most common (and cheapest) single-ply is EPDM (or ‘rubber’), although PVC and TPO membranes are also used.
|
EPDM is generally the lowest cost for shorter-term roofing or large-scale installations
~10 to 15 year lifespan up to 20+ years with enhancements/maintenance.
Can be used in specialty roofs (green or garden roofs), or no-odour, no-VOC situations
|
Less durable, more susceptible to damage and punctures than multiple ply roof.
Source of leaks can be hard to pinpoint.
Specialty roof systems (green roofs) can be expensive to design, install and maintain
|
| Modified Bitumen (MB)
|
Two-ply, reinforced membrane that can be mopped-on with hot bitumen, cold-adhered or torch-applied
|
Very durable and long lasting.
Easy to maintain & repair.
~ 18 to 25 years lifespan, up to 30 years with enhancements/maintenance
|
Can be more costly than BUR and EPDM.
Torch-applied membranes are very limited in use due to potential fire hazards and insurance implications
|
| Sloped roof
|
Layers of reinforced asphalt shingles, wood shakes, clay or composite tile; nailed or fastened to sloped roof
|
Varying durability
Common sloped roof application
Wide range of pricing and products
|
Sloped roofs only
Wide range of material quality and installation
|
| Metal
|
Single layer of metal over sloped roof.
|
Very durable and long lasting.
~ 30 to 50 years lifespan, up to 70+ years with enhancements/maintenance.
|
Costly to install compared to shingles
Sloped roofs only
|
The choice of roof system is crucial, and can be based on a number of factors including: type of
structure, existing or proposed conditions, accessibility, slope, roof traffic, tenants, interior
conditions and activities, cost and required lifespan.
Always hire a qualified, reputable and experienced roofing contractor. Remember that unqualified
installers, poor workmanship, inferior and/or incompatible materials will significantly reduce the
lifespan of your roof, leading to costly liabilities for your investment.
Please contact our office to discuss your unique roofing requirements with our team of roofing
professionals, who can assess the available options and determine what is best suited for your
situation.
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