REGULARS: QUALITY INSIGHT
Tiled roofing at Abrey Road Office Park.
cover too wide a span due to the required
pitch of 17.5⁰. In addition, tiles are better
suited for developments where cost is a
consideration – for the cost-conscious
developer or contractor, there could be
substantial savings.
Some themed housing estates specify
various tile profiles and colours to achieve
a certain look, for example the flat slate
concrete tile for an English feel or double
Roman Tuscan blend for the
Mediterranean look.
Best practice
Andrew Gove, director at GWR Roofing,
shares installation challenges and best
practice advice with us.
“Be sure that you are buying from a
reputable supplier – all the main suppliers
in South Africa are SABS approved and their
mark should be on the product. Don’t buy
cheap imports! Product and supplier
information is freely available online and it
would be a wise decision to read up on the
product you will be installing on the roof.”
Installing roof tiles or sheets has its
challenges. In terms of tiles, lifting the
trusses from their stacks to the roof can
take time and is hard work. Tiles that have
not been cured properly can result in high
breakages on site – normally a reputable
supplier will replace breakages, but time
and money is wasted in the process.
Gove further mentions that tiles that
have not been laid correctly will break or
chip when walked on. Poor batten
installation will affect the performance and
aesthetics of the roof. If the trusses are not
straight and the battens not lined, the roof
tiles will show obvious ripples and waves.
Battens that have been incorrectly spaced
will also cause a problem; if the battens are
WHAT TO CONSIDER WHEN CHOOSING ROOFING MATERIAL
• What is the function of the roof? Is it commercial, residential or industrial?
• Will the look complement the style of the building?
• What are the cost implications?
• How long is the roof expected to last?
• What is the prevalent weather in the area?
• In the case of a re-roof, what covering is most suited for existing roof trusses?
• What is the specified pitch of the roof?
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AUGUST 2018
CLADDING // CONCRETE // INSULATION // STEEL // THATCH // TIMBER // TRANSLUCENT // WATERPROOFING // COMPONENTS
spaced too close extra tiles will be used and
shortages will result. If the tiles are spaced
too far apart, the tiles could leak.
Generally, some roofing installers do
not lay ridges very well. They might
neglect to lay down a line of DPC before
laying the ridges, get the cement mixture
incorrect or not cut and clean the mortar
after laying the ridge. “Proper checking and
reporting of breakages of tiles by staff on
site is crucial, proper training of erector
staff is essential,” says Gove. Tiles are
robust and easy to work with if staff are
trained and know what they are doing.
Sheets can easily be scratched through
poor handling and are costly to replace.
Trimming sheets in the valleys and on the
hips can sometimes be untidy due to
incorrect training or a lack of proper tools.
The same goes for the installation of screws
– drills without a clutch are often used to
install tek screws (used to secure IBR or
corrugated sheeting to roofs); these
drills often overtighten the screw and
cause dents.
Lack of skill when it comes to installing
flashings, such as ridges and barges, often
results in poor finishing. It is not possible
to install sheets when the wind picks up
enough and a sheeted roof has to be totally
dry before people can safely walk on it to
continue installation.