Commercial Flat Roof Types Structural Info Blog

Commercial Flat Roof Types Structural Info Blog

There are many types of roof coverings for commercial flat roofs.  Each roof type has their pros and cons and some are better than others.

Modified Bitumen (MB) – Is an asphalt-type roof consisting of one, two or three ply systems.  This type of roofing material became more popular around the 1970s.  It is considered a built-up roof type.  With 100 square feet of coverage per typical roll, seems are unavoidable.

Thermoplastic PolyOlefin (TPO) – This is a single-ply roof membrane.  Since this type of roof material consists of 600 square feet of coverage per roll, seams are unavoidable though this type of roof material is installed fully-adhered and mechanically-attached or ballasted .

EPDM Rubber (ethylene propylene diene Monomer (M-class) rubber) – This is also a single-ply roof material.  It is made from synthetic rubber using recycled materials.  It has been around since the 1960s and is probably the most common type of flat roofing material.  It can last from 30 to 50 years if properly maintained.  This type of roof material also comes in rolls that consist of 1,000 square feet typically, so again, seems are likely unavoidable.

Dura-Last – This is a PVC type of roofing material.  Unlike the previous roof types, this type of roof material is factory prefabricated into panels of up to 2,500 square feet resulting in fewer seems then the previous three roof materials discussed.

Tar and Gravel – This is one of the oldest types of flat roof types staring as early as the 1840s.  It is a type of built-up roof covering and can consist of many plies.

The life of this type of roof covering depends on the number of plies.  A 3-ply built-up roof covering should last at least fifteen years.   Five years can be added to the life expectancy per added ply.

Polyurethane Foam Roofing – The most energy efficient of flat roofing materials.  Not only it is a good insulator, but also strengthens the roof and is excellent for colder temperatures.  These types of roofs can last 50 years or better if properly maintained.  Maintenance includes the roof being cleaned, primed and recoated at five years and then every ten years thereafter.  Polyurethane foam is also used inside homes as an alternative to common fiberglass insulation.

Green Roofs – Also known as rooftop gardens .  These types of roofs are becoming more utilized in our greener world.   These are also the most costly types of roofs and require the most maintenance as you could imagine.  The length of time this type of roof may last can vary greatly on a number of factors.

Photovoltaic Panels – Also becoming more popular in our greener world are solar panel roofing .  Though these are also costly, since they produce free solar energy they will eventually pay themselves off by saving money in alternative energy costs, such as electricity.  Maintenance is also minimal.  Like the green roofs, the length of time this type of roof may last can vary greatly on a number of factors.

How long your roof will last depends on various factors.  A roof should be well maintained and different roof structures require different types of maintenance and at different intervals in its lifetime.  The life of the roof will also depend on environmental conditions, the amount of foot traffic, slope, drainage and quality of workmanship.  If the roof is not installed properly, then its lifespan will be shortened.

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