High capacity rainwater systems get
to grips with extreme rainfall events
Following the wettest February on record, the UK’s Met Oce has said increases in winter rainfall and
extreme rainfall events are expected to become regular features of our climate during the 21st century. This
has major implications with how we construct our buildings, and their ability to deal with these changing
patterns in rainfall. Its why high capacity rainwater systems are seen as a critical part of the longevity of
these buildings, says Paul Wadsworth, specification manager at Brett Martin Plumbing & Drainage
It’s crucial that every UK building
includes a high-quality rainwater
system that will provide it with the
maximum protection from heavy and
intense rainfall. When specified correctly,
this vital building component will remove
rainwater quickly and efficiently, and
is a necessary part of any building’s
Guttering and drainage are legally
required to be in good working order
under Part H of the Building Regulations.
The specifier or contractor should give
consideration to a number of factors,
such as weather conditions, the potential
impact on the underground drainage
layout, the roof size and pitch, gutter
capacity and support, expansion
allowance and fall calculations in any
efficient rainwater system design.
When specified correctly, rainwater
systems should also complement the
building’s aesthetics and be tested to the
relevant industry standards.
To meet the requirements of larger
commercial projects – factories,
warehouses, agricultural and residential
roofs – high performance rainwater
systems with a larger profile offer
increased drainage capacity to allow these
larger roofs to be drained more efficiently.
They also require fewer discharge points,
reducing the number of downpipes to
provide both material and installation
savings on newbuild and refurbishment
projects. This can also compliment
building design, as there’s less downpipe
Heavy duty solution
When it came to the conversion of a
timber framed Warwickshire riding
stable into three contemporary homes, the
builder required a system, which would
remove rainwater quickly and efficiently
from the large cedar tile roof.
Brett Martin’s Deepstyle 170
Industrial Rainwater System was up
for the challenge, offering long-term
performance, ease of installation and
increased drainage capacity.
Located in the hamlet of Chadshunt
near Kineton, Warwickshire, the timber
frame riding stable was part of Chadshunt
Farm and built in 1920 for the training
and schooling of young horses.
When the owner decided to alter and
refurbish the existing building into three
four-bed luxury homes, builder Johnson
& Johnson specified rainwater materials,
which would ensure the future integrity
of this historic building, by removing
rainwater efficiently and protecting it
from water ingress.
To achieve the desired performance
and aesthetics for the 30m long roof,
Johnson & Johnson chose Brett Martin’s
super-sized Deepstyle 170 Industrial
Rainwater System in black, which has a
capacity of 11.54 litres per second1. This
robust and hardwearing system is able to
accommodate the increased volumes of
rainwater on this large steeped roof area.
With its super-sized 170mm
profile, Deepstyle 170 was developed
to accommodate increased drainage
capacity on larger commercial, industrial,
agricultural and residential roofs.
The system features new factory fitted
CLIP & SEAL technology on all fittings, so
that the specially designed captive seal is
held securely within the fitting, whilst the
clip locks the seal firmly in place during
installation for exceptional long-term
Deepstyle 170 integrates seamlessly
with Brett Martin’s 110mm Industrial
Downpipe System, and is part of the
company’s rainwater portfolio, which
includes 106mm Prostyle, 112mm
Roundstyle, 114mm Squarestyle and
115mm Deepstyle, in addition to the
Cascade range of cast iron effect guttering
and downpipe profiles.
Manufactured in the UK at Brett
Martin’s own quality-assured BS EN ISO
9001:2015 certified factories, the Deepstyle
170 system is tested to EN 1462 Load Class
H to withstand heavy duty snow loading.
In addition to the black colour option,
the high gloss PVC system is also
available in grey and has been proven to
retain its aesthetic with UV protection
providing long-term colour stability –
backed by a 10-year colour warranty.
Integral to the overall aesthetics
and the performance of the building
itself, rainwater systems must not be an
afterthought, but considered as a key part
of the design process.
Rainwater systems play an essential
role in collecting and removing rainwater.
When you get the specification wrong,
it can spell disaster for the fabric of the
building. High capacity drainage systems
are proven to adequately dispose of heavy
rainfall on large roof areas, and will stay
looking good and working well for years
to come, whatever the weather.
1 Actual test results calculated in site conditions given a
fall of 1:350 and maximum roof area 550m.
with a 170mm
has a capacity
of 11.54 litres
was the ideal
solution for the
64 www.rcimag.co.uk May 2020