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Single Ply Rubber
Roof
Martin Roofing Services, Inc has more
than 30 years of experience installing
and repairing Single Ply Rubber Roofing
as well as numerous additional roofing
products. We've provided a simple guide
as to what some of those most common
single-ply solutions offer. Most people
trust their roofing contractor to
provide them with guidance such that
you'll make the best decision for your
home or office roofing need.
Call us at 1-800-421-4170
for a FREE ROOFING ESTIMATE or
email us. You can also use our
convenient
online request form to inquire about our
metal roofing services or to request a contact.
Single ply roofing products were born
out of the oil crisis of the 1970s,
which led to lightweight, flexible roof
membranes. Today, a variety of single
ply roofing products exist.
Among the common single ply roofing
products are PVC, EPDM, TPO and KEE. All
these changes mean that selecting
single-ply roofing needs to be done with
care and forethought. Here is a brief
overview of the leading single ply
roofing products on the market today.
Single-ply membranes are usually broken
down into two subgroups — thermoplastics
and synthetic rubber. (Modified bitumen
membranes are virtually never installed
as single-ply membranes.) Thermoplastics
have a common characteristic not found
in synthetic rubbers — they can be
heated and reshaped or melted multiple
times. Because of this, the most common
method of seaming a thermoplastic is by
heat-welding the membrane. Properly
melting the edges together fuses the
membrane into a strongly bonded seam.
There are two major thermoplastic
membranes currently on the market. These
are polyvinyl chloride (PVC) and
thermoplastic polyolefin (TPO).
PVC roof membranes have the longest
track record of any thermoplastic
membrane, with the first PVC-based
systems installed in Europe in the early
1960s. Vinyl membranes are inherently
self-extinguishing, which enables them
to earn fire ratings from Underwriters
Laboratories and Factory Mutual and to
perform reliably in real-world flame
exposure.
The finished vinyl roof membrane
contains polyester or fiberglass
reinforcement, vinyl resins,
ultra-violet light inhibitors,
heat-stabilizers, biocides, pigments and
plasticizers. Polyester reinforcement
imparts high tearing and breaking
strengths needed for mechanically
fastened roofing systems. Because PVC is
not naturally flexible, plasticizers are
added to the formulation. In past years,
the loss of the plasticizers in
un-reinforced membranes caused
catastrophic failures as the membrane
reverted to its inflexible state and
shattered during cold weather. Now, all
PVC membranes are reinforced, and new
formulations minimize the loss of
plasticizers from the membrane.
TPO membranes have become widely used as
roof membranes in the past ten years. A
TPO roofing membrane is typically made
from polypropylene and
ethylene-propylene (EP) rubber
polymerized together using
state-of-the-art polymer manufacturing
technology. This technology enables the
production of TPO membranes that are
flexible at low temperatures without the
use of polymeric or liquid plasticizers.
Unlike some other popular thermoplastic
roofing membranes, the TPO polymer does
not contain chlorine and no
chlorine-containing ingredients are
added during sheet production.
The TPO resin is compounded with other
components, including a weathering
package, fire retardants and pigments,
to create a product that can withstand
the elements associated with rooftop
exposure. TPO itself is not fire
resistant and requires the addition of
fire retardants to obtain a fire rating.
The ratios of weathering material and
fire retardants are still inconsistent
from manufacturer to manufacturer.
Because TPO membranes are inherently
flexible, unlike PVC membranes,
additional plasticizers are not required
in the formulation so there is little
danger of plasticizer migration.
Synthetic Rubber: EPDM
Virtually all synthetic rubber roof
membranes are EPDM. Synthetic rubber is
a thermoset, which means once it has
cured, it cannot be melted and reshaped.
Consequently, the rubber membrane is
seamed by an adhesive — generally either
a field-applied contact cement or an
adhesive tape that is applied in the
field or factory and activated by
removing a release paper. Tapes have
become the de facto standard as they are
generally easier to apply, reducing the
chances they will be installed
incorrectly.
EPDM membrane rolls can come as wide as
10 feet. Wider rolls require fewer
seams. Fewer seams means less chance of
seam failure. Because of the roll sizes,
EPDM is often used on buildings with
very large roofs. EPDM can stretch and
relax, so it can easily accommodate
thermal expansion and contraction on
large expanses of roof.
Like PVC, EPDM roof membranes have been
in production for more than 30 years.
The systems have gone through several
enhancements over time — reinforcing has
been added, new seaming and flashing
methods and materials have been
developed, and white membranes and clean
sheets that minimize on-site dust
contamination have been introduced — but
the basic product is still the same and
performs well.
The majority of thermoplastics come in
white with other pastel colors
available. These white membranes give an
initial high reflectance value that can
help keep the temperature of the roof
and consequently the inside of the
building cooler. As the roof becomes
older and collects dirt, however, this
initial value will decrease unless the
roof is periodically washed. Synthetic
rubber is available with a white
surface, but the more durable membrane
is a dark grey color. There are white
acrylic coatings for EPDM membranes that
can give the same reflectance as the
thermoplastics and are advertised as
increasing the longevity of the roof by
as much as 5 to 10 years.
Call us at 1-800-421-4170
for a FREE ROOFING ESTIMATE or
email us. You can also use our
convenient
online request form to inquire about our
metal roofing services or to request a contact.
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