Naturally you'll compare shed quotes between the various shed companies. Looking up shed prices in
the local newspaper can be misleading. Often these are for sheds designed for the
least severe conditions in Australia.
You need a competitively
priced shed, without sacrificing strength, that's suited to your conditions. Below are some points
of comparison (and technical stuff) you need to know in order to make an
informed decision...
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check the wind region and terrain category
Your shed must be designed to suit your conditions. Your quote should
clearly state what wind region and terrain category your shed has been
designed for. (Caution: If you knowingly build a shed unsuited to your region
and you incur damage in the future, insurance companies could reject
your claim for damages to the shed and its contents.)
Some shed companies may use terms other than wind region and terrain
category as a measure of the shed's strength which may confuse you.
At the end of the day, to compare shed strength between quotes, look at
the frame sizes. (See Understanding frame sizes below.)
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sheeting base metal thickness (bmt) and total coated thickness (tct)
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The thickness of steel is usually specified as BMT (base metal thickness). This gives
a measurement of the steel thickness BEFORE PAINTING, and is a true indicator of the strength of
the steel sheeting.
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TCT (total coated thickness) measures the steel AFTER PAINTING.
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Colorbond® paint coating is .05mm.
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On your quotes from the various companies, you should be told the thickness of the
sheeting on the roof, walls and rollerdoors (if applicable). Therefore, make
sure you are comparing either BMT or TCT. The table below gives an
understanding of the different Colorbond® steel thicknesses that
should be provided in the various shed quotes from each company.
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.35mm BMT = .40 TCT
.42mm BMT = .47 TCT
.48mm BMT = .53 TCT |
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roof sheeting (cladding) minimum thickness
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All shed roof sheeting (cladding) must be 0.42mm bmt (i.e. 0.47mm tct) or above. Manufacturers
stipulate this.
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wall sheeting (cladding) minimum thickness
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Shed wall sheeting (cladding) may be 0.35mm bmt (i.e. 0.40mm tct) or above in non-cyclonic
areas (Wind region A or B). In cyclonic areas (Wind region C or D), shed wall sheeting must be
0.42mm bmt (i.e. 0.47mm tct) or above. If you are not sure of your wind region,
click on your state for more information.
Queensland,
NSW,
Victoria,
South Australia,
Tasmania,
Western Australia,
Northern Territory
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understanding shed frame sizes
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To make a judgement about the strength of your shed, you should know
the size of the frames and what contributes to strength.
You will be pleased to know that this technical stuff is basic common sense. Generally, the wider
and thicker the steel is in the frame, the stronger it is.
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| shed portal frames (columns and rafters)
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End wall portal frames are generally lighter than internal portal frames (unless you
you have an open end wall).
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The wider apart the shed portal frames, the stronger they need to be. Wider bays
need stronger portal frames, (but there will be fewer portal frames in the shed).
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Using an "embedded column footing" increases the performance of the column allowing
the use of lighter frames in some circumstances.
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| purlins and girts
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The wider apart the shed portal frames, the stronger your purlins and girts need to be. Wider bays
need stronger purlins and girts.
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A greater distance between purlins or girts (i.e fewer purlins or girts) requires stronger
purlins and girts.
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Overlapping purlins and girts increases their strength. Up to a point, more overlap means
greater strength. shedsales.com.au uses at least 18% overlaps on purlins and girts.
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Your choice of roof sheeting and wall sheeting will affect the minimum number of purlins
and girts you need. Click on the following links for more info...
roof sheeting (non-cyclonic)
wall sheeting (non-cyclonic)
roof sheeting (cyclonic)
wall sheeting (cyclonic)
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fixing of pa doors and windows
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To make a judgement on the quality of pa doors and windows you will need to
know how they are fixed in place.
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If pa doors and windows are not firmly attached to the shed frame, they
may not endure the severe conditions your shed may be subject to
over the coming years.
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Do the windows and pa doors attach to C-section or Z-section
frames that firmly fix to the girts, or are they screwed or
riveted to the sheeting?
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For a weather-proof quality finish, you will need flashing around
all sides of windows and 3 sides of pa doors.
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flashing, gutters and downpipes
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We provide gutters and downpipes as 'standard' in our quotes.
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Also as 'standard', we include corner flashings and
flashings around every door and window. This is essential for
weather-proofing and a neat appearance.
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