PITCHED ROOFING
Technical tips –
clay plain tiles
Tom Woodhouse, site services manager at Marley Eternit, answers contractor questions about installing clay
plain tiles
Plain tiles made from clay have
been used to cover roofs in
Britain for over 800 years and
they form much of the character
of the roofs seen in the South East of
England and the Midlands.
If you’re looking to add warmth and
character to either a refurbishment or
newbuild project, then clay plain tiles are
a great choice. Although some roofers do
have concerns about installation being
time consuming or difficult, this doesn’t
need to be the case, providing you plan
carefully, pay attention to detail and have
the right tools.
Here we take at look at some common
technical queries:
1. Will I have to cut clay
plain tiles?
Cutting is one of the most frequent things
our technical team gets asked about clay
plain tiles. Clay is a natural material
and following the firing process, during
manufacture, it becomes very hard. This is
great from a long-term durability point of
view, but it does mean the tiles are harder
to cut than equivalent concrete tiles.
In order to reduce the amount of
cutting required, planning is very
important to ensure the best fit and
largest width of tiles can be used, while
also maintaining the broken bond laying
pattern. Small pieces should be avoided.
Experienced roofers will adapt to and
account for these factors to ensure they
can create a high-quality aesthetic finish.
However, regardless of planning and
experience, you can’t avoid cutting clay
plain tiles altogether. It is inevitable
that cuts will be required during the
installation process, for example, when
completing hip and valley detailing,
where raking cuts to roof tiles will be
required.
2. How should I cut the tiles?
All cutting and drilling of tiles should
be carried out in well ventilated areas
to prevent the inhalation of dust, in
accordance with health and safety
recommendations. Wherever possible,
avoid dust inhalation by using cutting
equipment fitted with dust extraction
or dust suppression. Always wear
appropriate personal protective
equipment (goggles, protective clothing,
ear defenders and an approved respirator)
when mechanically cutting tiles.
Avoid cutting tiles that are laid in situ,
particularly open valleys, as this may
cause damage to the valley lining and
is also a health and safety hazard. After
cutting or drilling tiles, brush off all dust
from the surface to avoid staining.
3. What tools should I use?
Traditionally roofers would have used a
scribe and hammer, or pincers and this
method is still used today. However, these
days most contractors will use power
tools that are specifically designed for a
hard material, such as a diamond tipped
masonry disc cutter. These must be
used with appropriate dust suppression.
Further guidance can be sought from
your tool supplier or Marley Eternit’s
technical advisory service.
4. I’m creating a curved roof,
what tiles should I use?
Double lap tiles are the only small
element roofing materials that lend
themselves to curved roofing. Single lap
interlocking tiles are not suitable.
In particular, our Acme Double Camber
range is ideal when you want to create
a curved roof because of its latitudinal
camber. However, all of our Hawkins
and Acme Single Camber tiles can also
be used to create curved roofs and you
can get advice on how to do this from
our technical team. As an advisory
note, we do recommend that curved
roofing projects are only undertaken by
experienced roofers.
5. How do I cut Double
Camber tiles?
Some taper cutting will be required
subject to the radius of the curve. BS 5534
also states that the sidelap should be no
less than 55mm.
6.What are the main things to
consider when installing clay
plain tiles?
Careful planning and attention to detail
are crucial – don’t rush into fixing the
tiles. Attention to detail will pay off with
the end-result that you get.
Thoughtful specification of tiles will
give you the best finish and take time
to select the most appropriate fittings
for each project. Fittings can make a
big difference to the overall look of the
finished roof, more so on clay roofs than
with any other roofing material. For
example, bonnet hips or arris hips will
both give a different aesthetic on the
finished roof, even though they serve the
same function.
w www.marleyeternit.co.uk/clay
Quintain
House features
Marley Eternit’s
Acme double
camber clay
plain tiles
88 www.rcimag.co.uk July 2018
/clay
/www.rcimag.co.uk
/clay
/www.rcimag.co.uk
