REGULARS: QUALITY INSIGHT
Be roof cover clever
Covering a roof can be achieved using various materials; we look
at roof tiles and roof sheets and what to select for commercial,
industrial and residential sectors.
By GWR Roofing | Photos by GWR Roofing
Sheeted roofing at Camp Orchards wedding venue.
W
hen it comes to choosing a
roofing material, generally the
homeowner or client needs to
answer several questions before making a
final selection: what is the function of the
roof? Will the selected covering
complement the style of the building? What
are the cost implications?
However, the choice of roofing material
is mostly dependant on the homeowner or
client’s personal preference. In some
housing estates, the choice of roofing
material is dictated by the estate itself to
maintain the aesthetic of the estate. The
function of the roof also determines the
materials – for instance, a warehouse or
factory must use sheets due to the long
span and low pitch usually associated with
these types of buildings.
In terms of application, when it comes
to market sectors such as commercial,
industrial or residential, sheets may work
well in all three applications although they
really come into their own in the industrial
market. Tiles are well suited for commercial
and residential markets.
Tiles or sheets?
Why would you choose a roof tile over a
roof sheet? The life span of tiles is longer
than that of sheets. Roof tiles are very
diverse, boasting a plethora of different
profiles, colours and colour blends. The
design range is wider than that of sheeting,
giving architects and homeowners more of
a creative choice with regards to the look
and feel of the roof and building in general.
When it comes to pricing, tiles are more
cost effective than sheets, however, it costs
less to kee p a sheeted roof maintained.
Tiles are more resistant to corrosion than
sheets, especially in coastal areas.
Aluminium sheets are more resistant than
zinc alum sheets – in fact, zinc alum sheets
should not be used within 5km of the coast.
Tiled roofs with a pitch below 17.5⁰ will leak
due to the low pitch. Sheets are a better
choice on low pitch roofs and profiles such
as IBR or saflock are well suited for low
pitch roofs.
From a security point of view, sheets
offer better security than roof tiles, which
can be removed to gain access to the ceiling
void of a house, whereas sheets are
physically screwed to the purlins. High wind
areas could be better suited for sheets which
have been positively fixed to the purlins.
Metal roofs are considered green as they
can be recycled and produced from
recycled materials. Sheeted roofs also use
less timber in the roof structure than tiled
roofs. For a sheeted roof the maximum
centres of the roof trusses are 1.2m as are
the 50x76 purlin distances. The trusses for a
tiled roof are spaced at a maximum
distance of 760mm and 38x38 battens are
spaced between 320 and 340mm.
Tiles are suited for residential and
commercial projects where the roofs don’t
CLADDING // CONCRETE // INSULATION // STEEL // THATCH // TIMBER // TRANSLUCENT // WATERPROOFING // COMPONENTS
AUGUST 2018
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