CPD Specifier May 2015 issue September 2015 | Page 29
Roofing
Bradford - The new Pardak® 110 system has been installed on the roof of another
Westfield scheme - the Broadway in Bradford, opening later this year
Innovations in Rooftop Parking
In 1987, Netherlands based manufacturer
Zoontjens launched Pardak®, an innovative
decking system for roofs accommodating
intensive passenger car traffic and parking,
based on tensioned precast concrete slab
technology. Almost 2 million square metres
have now been installed around Europe - and
development continues with new ranges to meet
the latest demands.
Rooftop parking is an increasingly popular
design choice, making good use of wasted,
high-level areas and freeing up much-needed
open space on the ground for more attractive
and appealing uses, adding value to our cities.
But the technical challenges are complex,
demanding dedicated expertise and a holistic,
systematic approach. The Pardak® system can
be used on most roof build-ups including warm,
un-insulated and inverted roofs where it sits
directly on the insulation so eliminating any cold
bridging. It uses dry, prefabricated construction
techniques for fast, safe installation, unaffected
by most weather conditions - which can be
speeded up even more using mechanized
techniques such as vacuum-lifting machines.
The system consists of high quality, vacuumformed concrete slabs supported on pressure
distributor pads with adjustable tensioning
elements. Each slab is profiled on the sides with
drainage slots and supplied as standard with
a raised diamond pattern. A reinforced version
is also available to accommodate emergency
vehicle access.
MEETING SUDS REQUIREMENTS
The regular pattern of surface grooves in
the slabs and the pre-formed slots between
installed slabs allow water to move rapidly off
the surface without the need for falls, into the
void below. Here, water runoff can be attenuated
before discharge, as part of a SUDS strategy
to meet the latest planning requirements for
sustainable drainage introduced earlier this
year in England. The surface remains free of
water - and ice in cold weather - making it safe
for both vehicles and pedestrians. The void
below can also accommodate service cables
with straightforward access when needed.
The paving system protects the waterproofing
membrane from UV, structural and other
damage, while keeping it accessible, as
individual slabs can be removed easily. In fact,
the whole system can be rapidly dismantled and
re-used where needed.
ZOONTJENS
Stratford - Around 15,000m2 of Pardak®
rooftop car park paving is in use at
Westfield Stratford City - Europe’s largest
urban shopping centre
Pressure distributors at the corners of slabs
absorb and distribute vertical and horizontal
forces that occur when a vehicle passes over
the parking surface and also reduce contact
noise of the vehicle tyres. Then, bolts in the
tensioning element are simply adjusted to
close the slabs up, creating an integrated,
homogeneous surface. Here, vertical, as
well as horizontal forces exerted by vehicles
braking, decelerating and turning, are distributed
between several slabs. The adjustable
tensioning elements compensate for differential
movement of the slabs. The adjustable
tensioning elements compensate for differential
movement of the slabs, because of their selfregulating action. They also accommodate
thermal movement of the building and the slabs,
and movement of the slabs due to heavy traffic,
as well as product and installation tolerances.
NEW PRODUCT RANGES
Recent examples of this impressive system
include Westfield Stratford City - the largest
urban shopping centre in Europe and the
gateway to London’s Olympic Park - where
around 15,000m2 of the well-established
Pardak® 90 were installed. But the recently
developed Pardak® 110 range, replacing
Pardak® 90, takes these principles further
with improvements to accommodate today’s
increasing trafficking levels and heavier cars
including SUV’s.
TEL: +31 (0)13 5 379 329
The main changes are considerably more
effective tensioning elements, plastic corner
pieces enabling accurate slab height levelling
and increased slab sizes to a 1100mm
x 1100mm grid. Pardak® 110 also gives
substantially lower sound generation values,
for example from shopping trolleys, due to a
more intensive horizontal and vertical tensioning
of the new system. Its capabilities will be
demonstrated at another Westfield scheme
opening later this year - the Broadway in
Bradford - the fourth largest shopping centre in
the UK and the first to use Pardak® 110, where
some 13,000m2 have been installed.
Zoontjens is also turning its attention to
renovation and refurbishment projects, and
lightly trafficked roofs such as office blocks and
car dealerships. Here, the smaller and lighter
Pardak® 80 system imposes lower loads on the
roof structure but has been designed to cater
for the increased weights and dynamic power of
today’s cars. The prefabricated and tensionedslab paving system can also be installed
quickly to minimise ‘down-time’ - particularly
when machine-laid - while rejuvenating older
damaged roofs. Finally, a growing demand for
rooftop paving that can handle heavy goods
vehicles has led to the development of Pardak®
XL, a driving surface consisting of 2 x 2 metre
concrete slabs able to support 16 tonnes.
WWW.ZOONTJENS.NL
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