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CONSTRUCTION WORLD
NOVEMBER
2016
PROJECTS AND CONTRACTS
drum at ground level (where the building’s utilities are concealed behind
a slatted timber screen).
All shapes cut from the weathering steel plate had to fit into the laser
cutter’s maximum size restriction, as well as the allowance for shapes
that can be folded. All components of the steel structure needed to be
transported to a site with narrow driveways. The house is situated high
on a slope without any direct vehicular or crane access. Components
were pulled to the site on a sleigh with a winch, and then hoisted up by
means of a gantry supported by scaffolding surrounding the house site.
Getting to a building inaccessible by road proved challenging. Some of
the larger components were winched up an embankment to the position
of the construction site. The site was enclosed in a scaffold structure
that was covered with a tarpaulin and hail netting so that work could
take place during the rainy season. Chain blocks were attached to two
I-beams at the top of the scaffold structure to raise and lower compo-
nents into position.
The slender nature of the vertical steel structural elements meant that
there was flex in the structure when loaded and the steel structure had
to be braced prior to the timber being installed. What makes this project
special is the high level of customisation and detail required, with very
small manufacturing and assembly tolerances. Steel was used to express
the natural structural systems of the trees surrounding the house.
Global roofing solutions metal cladding winner
New Office for Statistics South Africa
Over and above its aesthetic appeal is the innovative use of metal side
cladding on a commercial building, which is most unusual these days.
It’s also unusual and interesting because on this state of the art modern
building, we have a profile used that dates back to the 1960s. Another
thing that impressed me was the incredible quality of the workmanship.
In this type of an application you really have to pay attention to the
detail, or the cladding will look very tacky very quickly.
The Stats SA project consists of new offices and an archive building.
Roof and side cladding is 0,58 mm thick galvanized Z200 GRS Brownbuilt
406 profiled sheeting with standard Chromadek finish one side and
standard backing coat to other side. Sheeting colours include Dove Grey,
Dark Dolphin and Charcoal. Insulation used over purlin on roof and sides
were 40 mm thick white faced Lambdaboard and Sisalation 405.
The site was extremely congested and installation programme dura-
tion very short. The buildings were high, with lots of angles and direction
changes on sides. Underslung sheeting in long lengths in Brownbuilt
406 profile tapered with angles. The Architect requested concealed-fix
flashings. In order to address these challenges, the main contractor
assisted with cranage and special scaffolding. Another solution included
the design of special clip-on flashings.
All roof sheeting, side cladding and soffit sheeting is concealed-fix
sheeting. Majority of flashings was concealed-fix or designed to hide
fasteners. The most impressive technical aspect of this project is the
underslung Brownbuilt 406 profiled sheeting and special flashings.
OUTSTANDING STEEL APPLICATI
The project profile in this issue is Eastgate
Phase II redevelopment which was the overall
winner for the 2016 Steel Awards.
We also feature the two projects that were
joint winners for LSFB in the same awards in
the ‘environment and sustainability category’
as LSFB has various green properties. Here
we feature the remaining category winners
in the 35
th
annual steel awards.
Residential category winner
The Tree House Constantia
Winner of the Residential Architectural Category, The Constantia Tree
House is a custom designed residence that embodies both simplicity
and luxury. Getting all steel components to a sloped site without direct
vehicle or crane access meant using both a sleigh and then chain blocks
attached to two I-beams on the top of the scaffolding.
One enters the floating building by means of a weathering steel
bridge with a timber deck walkway. The lowest floor contains a living
area and kitchen, with two double volumes and a circular stair linking
the living area visually and physically to the bedroom level above. Large
sliding doors, 6 m high, open up the living level to a balcony overlooking
the estate’s gardens
A circular stair, with sculptural treads carved from solid standing
laminated oak, and supported on weathering steel steel reaches, lead up
to the bedroom level (with bathroom), and then further up to a roof deck
with views over the Constantia Valley.
The structural system was executed in laser-cut weathering steel
plate, bent to form facetted columns, branch-like arms and rings. There
are four structural column clusters, each consisting of four weathering
steel columns held together with the arms and rings, to support spruce
and western red cedar floor beams. The columns are bolt fixed by means
of a large circular baseplate on conical concrete pad footings.
There is no steel connection between any of the steel structural
columns but the timber floor plate construction. The stair ‘drum’
consists of a half circular lattice framework of mild steel hollow tubing
and angles – bracing the structure as it is bolted down onto a concrete