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.
“This project really stood out for me. I think it’s a very special
structure. Small, but very special.” – Prof. Alex Elvin, WITS
University, Engineering.
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, 6m 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 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 faceted columns, branch-like arms and
rings. There are 4 structural column clusters, each consisting
of 4 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 drum at ground level (where the building’s utilities are
concealed behind a slatted timber screen).
Steel Awards
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 components 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.
Client / Owner / Developer: Graham Paarman
Architect and Nominator:
Malan Vorster Architecture Interior Design
Structural Engineer: Henry Fagan & Vennote
Quantity Surveyor: DA Quantity Surveyors
Main Contractor: T. Naude
Steelwork Contractor: Link Engineering
Photographer:
Micky Hoyle, Condé Nast House & Garden
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