Standing
seam metal roofing roof flashing
Kalzip - bridges the gap between form and function
The chosen material used to roof “one of
the most prestigious toll canopies in Europe” had to be robust
enough to withstand an extreme environment, flexible enough for
the complex design and aesthetic enough to please the occupants
of the 50,000 vehicles that use it every day.
Kalzip’s stucco embossed standing seam ticked all those boxes
and more for Harris McMillan architecture + design who conceived
the new canopy which combines a contemporary look with
reflections of Brunel’s’ cylinder girder railway bridge that
runs alongside the Tamar [road] Bridge.
Now the crowning glory of the new toll plaza, the 500 m² of
Kalzip aluminium standing seam have been curved and tapered over
six half and two quarter “scallops” … and eight metres over
multiple lanes of traffic which remained active during the
construction.
The £4.5 million project comprised rebuilding the toll plaza
with new booths, realigned carriageways and an electronic
tolling system which required overhead tag readers.
“These could have been mounted on a simpler frame structure but
the client decided to put a new canopy over the roadway and
booths which would also carry the tag readers,” said Robert
Harris of Harris McMillan.
“Because of the historic importance of the railway bridge, a
well-conceived and striking architectural treatment of the
visible structure of the toll plaza was vital. We designed the
canopy using three dimensional computer models and came up with
a double curved segmented roof."
“We considered various covering materials for this and involved
technical staff from Kalzip at an early stage. They confirmed
that their cladding systems could cope with the complex design
and we were impressed with the attractive options available."
“The structure is subject to extreme weather conditions and also
to fumes etc from constant traffic. The material will withstand
all these. The client was delighted with the elegant design we
produced which while being fully contemporary, contains some
deliberate subliminal echoes of Brunel’s bridge. The client is
also very pleased with the finished product. We have specified
Kalzip previously and would certainly do so again.”
The use of Kalzip on the double curved roofs necessitated some
complex steelwork for the secondary support elements and a
challenging working environment for roofing contractor Bowline
Roofing & Netting for main contractors Dean & Dyball
Construction.
Managing director Tony Marsh said: "We feel it is a fine example
of the flexibility of Kalzip. The whole project was achieved
without the requirement for any welding to create the tapers and
curves. With the correct product we have been able to provide a
robust and aesthetically pleasing structure to our client who
was overjoyed with the finished result.”
The Tamar suspension bridge , which carries the A38 across the
river between Plymouth on the west bank and Saltash, Cornwall,
on the west, is in public ownership, being owned and operated
jointly by Cornwall County and Plymouth City Councils.
It was originally designed by Mott Hay and Anderson and when it
opened in 1961 with a main span of 335 metres was the longest
suspension bridge in the UK. It was strengthened and widened at
a cost of £35 million in 2001.
Email: tracy@tlcpr.co.uk