DesignBuyBuild_16_2015

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 muchneeded
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.
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,
because of their self-regulating 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 SUVs.
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 tensioned-slab 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.
For more information about Zoontjens’
comprehensive range of rooftop paving
systems, visit www.zoontjens.co.uk or
email info@zoontjens.co.uk.