Roofing

Full-size laboratory testing of typical roof sections was
undertaken and after some revisions and modifications approval of
the roof design was given. "A new assessment was undertaken in
cooperation with Kiwa BDA" said Richard Verlijsdonk, project
manager of the Netherlands roofing contractor, Ridder Skins for
Buildings, "and we are delighted to have gained approval for the
system." The successful testing allowed a BDA Agrément® to be
issued by Kiwa BDA ECBE.
With the roof’s specification tested and approved, construction of the
building could begin. The building comprises eight 200m long wings
- four on each side of a vast central open area called the Agora, itself
under a 38m high, arched roof. Each wing represents the ‘fingers’ of
interlocked hands (minus thumbs!) suggesting the design concept of
NATO’s partnership of nations.
All roofs are supported by a steel structure. The roof construction
comprises a steel deck on which a primer has been applied to aid
bonding of the 80 or 100 mm bitumen-coated insulation slabs that are
placed on top. Then comes a single layer of APP roofing sheets, 3 to
4 mm thick with a polyester support, which are pre-welded to the
insulating layer. Over that is a low slip PE film and finally the
profiled zinc sections. The 200m long roofs of the wings are divided
into nine compartments, separated from each other by gutters. The
lower five boxes are 18m long, the upper four 26m. At the lower edge
of the roofs is an aluminium box to allow connection to the facade
and the outside edges around the building, which also have
aluminum strips to connect to the facade construction.
t
Rainwater drainage, constructed by Belgian roofing contractors, ZDP
Zolderse Dakprojecten, is via 500mm wide gutters and syphonic
outlets to minimise the number of downpipes and connections to
underground drainage – effective water management is one of the
client's key environmental objectives.
The standing seam was profiled on site from the coils of the zinc
material supplied by manufacturers, Nedzink. Factory Production
Control (FPC) of this production, an important element of the BDA
Agrément, was undertaken by Kiwa Belgium. After the sections were
profiled, they were hoisted on to the roof via a mobile tower crane.
The long wings were built first and roofed, followed by the
intermediate roof sections above the Agora. This approach was
chosen in consultation with the other parties who worked on the
project, with safety as the highest priority. But the logistics of this
project were also very important and complex - not just from the
building process but from the security of this key NATO asset.
Anyone who had to access to the site had to be thoroughly screened
in advance, so rushing new personnel in to advise on or solve a
sudden site problem was simply not an option.
Kiwa BDA’s Chris van der Meijden said, "The NATO HQ building
was an amazing project to work on and we were very pleased to be
able to bring our expertise and test facilities to the table and
approve the roof design."
Kiwa in the UK comprises a range of diverse services. Carrying out
testing (and often certification) on appliances, construction materials,
electrical and water products. They are a Notified Body, and are UKASaccredited.
For more information please contact Chris Forshaw, Kiwa
BDA Business Development Manager (07718 570564).
Enquiry 40
The 200m long roofs of the wings are divided into nine compartments, separated from each other by 500mm wide gutters.
Page 40 Roofing Today