September 2019

Perfectly Pitched
THE CASE FOR CLAY TILES: A
MODERN OPTION FOR PROJECTS
Pitched Roofing Consultant John Mercer, writing on behalf of Edilians, explains why he feels
modern production techniques mean clay tiles are a great solution for many projects, but
stresses how important it is they are installed correctly...
Clay has been a material of choice for our
roofscapes for nearly 1,000 years; the
Romans are credited with introducing clay
roof tiles to Britain during their occupation from
43 AD until their departure in 410 AD, after which
the art of clay tile making was lost for a while.
Concrete roof tiles were first introduced into
Britain in the 1920s, though it was the huge
boom in housebuilding after the second World
War when they really found favour due to mass
production techniques and ease of installation.
Concrete quickly became the mass housebuilder
choice for roofing, accounting for around 60% of
all roofs, with 20% being slate and 10% being
clay. However, modern production methods and a
wide range of tile shapes and colours mean that
clay tile producers, such as Edilians, are now
challenging the dominance of the concrete
producers.
Thriving market
Good quality clay roof tiles can last well over 100
years, though it is more likely that other
components of the roof will require maintenance
or replacement well before the roof tiles, such as
battens, fixings and underlay. As we all know,
there is a thriving market in the UK for second
clay tiles.
When specifying roofing products, it is important
to choose materials that comply with current
British and European Standards to ensure a good
quality, durable roof for the client. Clay tiles
should comply with EN 1304 and must pass 150
cycles of the European test for frost resistance;
EN 539-2, to be deemed suitable for use in the
UK. Edilians’ clay roof tiles are produced from
high quality French clays that achieve pass
results far in excess of the European Standard
test requirements.
Installation
With regards to installation, all tiles and slates
must be secured to resist predicted wind loads.
The security of a roof tile or slate very much
depends upon its fixings; e.g. nails, clips, straps
etc. Slates are ‘double lapped’ therefore each
slate is afforded some protection to wind up lift
by its neighbouring slates. By the same
reasoning, double lapped clay plain tiles also
provide an extremely secure roof covering through
their small size and coverage. So much so, that
in many locations in the UK, plain tiles only need
mechanical fixing (i.e. nailing) in every fifth
course in the local and general roof areas, with
the perimeters having each tile mechanically
fixed. Of course, wind load calculations must
always be carried out to confirm this for each
location – contact Edilians Technical Support for
a fixing specification for every project. The
methodology for calculating roof tile fixings is well
documented in BS 5534: the British Standard
Code of practice for slating and tiling and pitched
roofs should be fixed to withstand wind speeds
only likely to be exceeded once in 50 years.
If natural slate is beyond a project’s budget, then
for an authentic slate appearance, Edilians has
developed its Beauvoise Graphite Slate, which is
the perfect substitute and it comes with other
advantages, such as the speed of installation, no
need for sorting and holing, as well as the
reduction in cost that only a single lapped roof tile
can bring. Being produced from clay, Beauvoise
Graphite combines the riven appearance of slate
with a natural clay material that will keep its rich
slate grey colour for the life of the tile and will
never fade.
Clay is much more than a great slate substitute;
over its 1,000 years’ presence in Britain, clay has
introduced many of the great roof tile shapes that
are now such a part of our roofscapes; for
example, pantile and roman, as well as
Mediterranean-influenced bold roll. Indeed, many
popular concrete tile shapes are very much
influenced by clay tiles.
Modern clay tiles are pressed, which means that
it is possible to incorporate endless technical
features into the upper and lower surfaces of the
tiles to improve security and weathertightness.
Clay is also twice as strong as concrete, which
means that clay tiles can be thinner and therefore
lighter in weight than concrete tiles. All this,
combined with the fact that clay tiles keep their
colour for life, means that they remain a great
option, whilst modern production techniques
mean that clay is not far behind concrete in
terms of cost and ease of installation.
Contact Edilians / John Mercer
www.imerys-roof-tiles.com
@imerys
@johnmercer3
46 TC SEPTEMBER 2019