Membrane roofs are attached in a variety of ways.
These roofs can be installed using techniques determined by the project’s specific requirements and material specified.
The most commonly used polymers are atactic polypropylene (APP) and styrene butadiene styrene (SBS).
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SBS imparts a rubber-like characteristic to the bitumen.
SBS cap sheets are usually installed using cold adhesives or hot asphalt tar.
On the other hand, Thermoplastic APP sheets are installed utilizing the torch-applied method.
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Built-Up Roofing
The grandfather of flat roofs is the built-up roof or BUR.
Built-up roofs have solved the low-pitch roof problem for ages, a challenge thatasphalt shinglescould never handle.
Thehot-applied asphaltor coal tar pitch blends with the bitumen-soaked roof felt, creating a monolithic roof membrane.
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The roof felt/asphalt tar layering is repeated in overlapping layers until the assembly is two to four thick plies.
They can last from 30 to 50 years.
Standing seam metal roofs have long metal panels joined at the seams with concealed fasteners.
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These panels are not bolted onto the roof.
Instead, they can contract and expand with climate conditions.
The most common metals used are steel, stainless steel, copper, and aluminum.
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Metal roofs are not the best option for roofs that have zero pitch.
If any pooling occurs, they can form leaks between the seams.
But due to their durability and recyclability, they are one of the more sustainable choices.
For instance, modified bitumen is your best bet to save money.
It has surpassed built-up roofs in popularity because they’re easier and quicker to install.
However, it only lasts about 15 to 20 years, half as long as single-membrane and metal roofs.
Built-up roofs are made of asphalt, boards, roofing felt, and gravel and are sealed with asphalt.
This method is considered the old way of doing roofs.
Black EPDM absorbs light and heats rooms underneath.
Black EPDM is favored in snowy regions since black rubber tends to melt snow faster.
Rubber makes more sense for commercial properties and has excellent longevity, lasting up to 30 to 50 years.
Consider a PVC or TPO single-membrane roofing material if you prefer white roofing.
It reflects light, keeping the space underneath cooler.
Single membrane roofs are easy to install by rolling out large rolls of the lightweight membrane.
However, they can show dirt quicker than other options.
The benefit of TPO over PVC is it has a higher puncture resistanceand is not as slippery when wet.
The least expensive material is modified bitumen.
TPO and PVC can last 30 to 40 years, while metal roofs can last 30 to 50 years.
Single-layer membrane and standing seam metal are the best roofs for their longevity and water-tightness.
Rubber (EPDM) or metal roofs are preferred for longevity, with lifespans between 30 to 50 years.
Determining which is better between EPDM and TPO depends on your climate.
Modified bitumen is the least expensive method for installing a flat roof.
Modified bitumen tends to last less, about 15 years.
EPDM: A Roof System for Every Climate.EPDM Roofing Association.
NYC CoolRoofs.NYC Department of Buildings.
TPOSCommodity or specialty?National Roofing Contractors Association.
National Roofers Contracting Association.
How much does flat roof replacement cost?Angi.
How much does a flat roof cost?HomeAdvisor.
