Knauf Insulation’s Polyfoam® Slimline System is featured in this
year’s Construction Products Association’s showcase publication,
Construction Products Innovations and Achievements. Specifically
designed for insulating protected membrane roofs, the system
consists of a base layer of Polyfoam® Roofboard beneath a vapour
permeable, polyethylene separation membrane that reduces the
‘rainwater cooling effect’ on the roof. Polyfoam® Roofboard is a
tough, high-performance, extruded polystyrene (XPS) insulation
board with a high compressive strength and is ideal for use in the
construction of the increasingly popular green, or living,
roofs.
Green roofs offer many benefits to developers, owners and users.
They are visually appealing; can make a building’s environment
quieter; can help regulate its temperature; can improve air quality
by removing pollutants and increasing oxygen levels; can ameliorate
water run-off in heavy rain; have a cooling effect from the plants
use of heat to evaporate moisture; have a positive effect on urban
biodiversity and bring enjoyment to those who use them – and all
win points with city planners! Creating ‘something from nothing’ –
and turning what would normally be considered ‘wasted space’ into a
positive aesthetic and environmental feature – has the benefit of
improving the value of the project for both its owner and
occupier.
There are two basic categories of roof garden: ‘extensive’ and
‘intensive’. Extensive roof gardens are ‘simpler’, usually being
designed for their aesthetic appeal and use lightweight sub-soils
that will support only a limited range of plants; typically,
sedums. Intensive roof gardens are designed for use as recreational
spaces, support a wide range of plants and sometimes require
irrigation and maintenance.
The load bearing capacity of the structure and the quality of the
components determine the success and longevity of either type. The
depth of soil needed to support an extensive green roof weighs
between 60 and 150 Kg/m² when saturated – surprisingly favourable
compared to paving slabs which generally weigh between 160 and 220
Kg/m² – but, as the depth increases to support an intensive green
roof, that weight can rise to 500 Kg/m². Clearly, if the insulation
material is going to have any chance of protecting the waterproof
membrane, it’s a fundamental requirement that it has the
compressive strength and impact resistance to withstand both the
soil’s weight and the odd prod from a gardener’s fork!
Polyfoam® Roofboard is a high-performance, extruded polystyrene
insulation board ideally suited for insulating green roofs. Made
from Polyfoam® Extruded Polystyrene (XPS), its high compressive
strength (up to 500 kPa), impact and moisture resistance provide an
outstanding structural insulation solution.
Polyfoam® Roofboard is available in three grades – Standard, Extra
and Super – giving designers the opportunity to specify the optimum
product to meet the intended use of the roof. The three grades
cater for everything from the light loads associated with
occasional pedestrian maintenance traffic, through the demands of
green roofs right up to the very high loads imposed by vehicle
movement. All have interlocking, rebated edges, come in one
manageable size (1250 mm x 600 mm), are available in a range of
thicknesses and are lightweight, easy to store, handle and
install.
For further information, please visit www.knaufinsulation.co.uk or
call the enquiries hotline on 08700 668 660 quoting PR 422
05.
– Ends –
(524 words)
® Registered Trademark of Knauf Insulation
© Knauf Insulation, 2005
© Photo: Paul Zanre