Poly Tarps are one of the most popular tarps available to consumers due to the
wide range of
colors, sizes, weights/strength and price. This document will provide the information you need to
select the right tarp for your application whether you are covering a canopy,
carport, construction job, tent frame, outdoor event, yard project or wedding.
Poly
Tarp Construction:
Poly Tarps are typically made of multiple layers with a woven mesh fabric
sandwiched between two or more polyethylene sheets. (TARPMAX can make maximum 5
layers) Polyethylene is the same material used in cables, pipes and molded
containers. It accounts for the largest portion of recycled plastics (recycle
codes 1, 2 and 3). There are many other features that should be considered as
well when evaluating your purchase. Consider the following list of tarp
features before deciding on the right tarp for your application.
Ø – This is the actual
thickness of the tarp measured in mils (1/1000 of an inch). The larger the
number, the thicker the tarp. Typical light weight blue tarps found in most
retail or hardware stores are about 6 mils. If
you are planning a heavy duty use, such as covering a carport, consider
a heavy duty tarp at 11 to 12 mils or a super heavy duty tarp at 23 mils.
Ø – The specified sizes of poly tarps will not be
the actual measured size. The sizes will vary from one manufacturer to another.
Be sure to check the descriptions for the tarps. Tarps will typically be 4 to 6
inches smaller in each direction than the specified size. If a tarp is specified to be 10 feet the
actual size will be 9 ft 6 in to 9 ft 8 in. This is due to the fact that tarps
are cut to size and then hemmed at the edges. The hem uses up some of the
original width leaving the tarp slightly smaller than specified.
Ø – Most poly tarps are
constructed with a mesh fabric laminated between at least two layers of
polyethylene film. Some heavy duty and super heavy duty tarps will have an
additional layer of black polyethylene laminated in the center to prevent sun
rays from penetrating the tarp. For some
specially used, Tarpmax provide 5 layers lamination, it have strong water resistance
ability.
Ø – The mesh fabric
specification is the number of threads per square inch. An 8X8 mesh count would
mean there are an average of 8 threads per inch in both the horizontal and
vertical direction. Heavier duty tarps will have from 12 to 16 threads per
inch. The thread weight may also be specified in denier. Denier is the weight
in grams of 9000 ft of thread. The larger the denier the heavier the thread.
Denier is not always specified but generally the heavier duty the tarp the
larger the thread.
Ø – Grommets are metal rings
lining a small hole at the edge of a tarp to accommodate the attachment of
cords or bungees to the tarp. Spacing of grommets will vary from 18 inches to
36 inches depending on the grade of the tarp. Higher grade tarps will have the
grommets spaced approximately 18 inches apart. Grommets may be made of aluminum
(rust proof but not the strongest),brass (rust proof and strong), or plated steel (rust resistant and
strong), and also plastic(Polycarbonate). The most durable and rustproof
grommets for outdoor use are brass.
Ø – Tarps may have additional
reinforcement around the perimeter of the tarp to help prevent ripping and
tearing. There are four main types of reinforcement.
o
Corner
reinforcement – The higher the grade of tarp the more likely you will
find heavy reinforcement in the corners. Corner reinforcement helps prevent
tearing out of the corner grommets and will extend the life of your tarp.
o
Perimeter
rope – This is a rope which has been sewn inside the hem at the edge of the tarp to add
reinforcement strength to the tarp.
o
Hem
– The hem is formed by folding the edge of the tarp back onto
the tarp and then stitching the entire hemmed area. Most poly tarps have a hem.
o
Grommet
reinforcement – In addition to the corners some tarps have additional
reinforcement at each grommet sometimes called a patch. This reinforcement is
added to the hem area of the tarp and is typically only available in the
heaviest duty tarps. Note that some heavy duty tarps may use additional
reinforcement in the hem to improve grommet strength and will not have the perimeter rope.
Ø – This is a chemical
treatment done when manufacturing the tarp to help protect degradation of the
poly tarp from UV rays.
Ø – Most poly tarps are
waterproof. The laminated film layers of polyethylene are naturally waterproof.
However, some screen poly tarps designed
for truck bed covers and sun screens are not
waterproof.
Ø – Since
polyethylene is water proof it also is resistant to rot and mildew.
Ø – No poly tarp is
flame-proof and should not be used near open flames or other heat sources. Some
flame retardant tarps are available. If you are purchasing a flame retardant
tarp, be sure you know and understand the specifications.
Ø – Sun blocking tarps have an
additional layer of black polyethylene and black mesh threads to form a light
blocking tarp.
Ø – Tarps come in a wide range of colors all of
which will not be covered here. Some tarps have special features that may be
required for your application.
o
Silver
Sun Blocker – These specialty tarps are designed with black
polyethylene and black mesh laminated between silver poly on one side and
either a light or dark poly on the other depending on the manufacturer. The key feature of these
tarps is that they block the sun light, and are cooler underneath in the
summer. These tarps are great for canopies and carports.
o
White
– These tarps are great in that they provide some shade but allow some natural light to come through.
Applications include wedding receptions, dining canopies and vendor booths.
o
Clear
– Clear poly tarps are great anywhere you need to have a lot of
light but still need to have protection from the weather such as green houses.
o
Blue,
Green, Brown – These tarps have no special color features but are great utility tarps for use in general
construction or landscape maintenance.
o These brightly colored tarps
are used where high visibility is
preferred.