COVER STORY
The roof overhangs throughout the entire structure.
columns to obscure the view over the pool
and surrounding bushveld.
Termed a ‘crowning jewel of the house’,
the floating steel roof overhangs the house
on every side with a minimum overhang of
1.6m. At its maximum, the roof overhang
extends in an 13m butterfly cantilever
creating a seemingly unsupported roof over
a boma. The total roof area for the 450m²
residence totals at an impressive 900m²
allowing inside spaces to blend effortlessly
with the outside.
Over 34 000 tons of steel was used for
the entire project. The steel roof arrived in
four parts, which was logistically possible
as the manufacturer, Quality Steel, was
located just over an hour away from the site.
The initial design included latticed
trusses, which would prove complex owing
to the complexities of a roof that features
valley and ridge connections. Rafters are
used instead which make connections and
layout much simpler.
10
MARCH 2018
RESIDENTIAL // COMMERCIAL // INDUSTRIAL
For small rooms, the roof was covered using
light IPE200aa sections. For the main open
span roofs (the lounge area and garage),
305UBx25 was used.
A column that was initially proposed to
replace a tree and support the garage roof
was removed opening up 90m 2 worth of
space, with open sides on two ends.
“For the columns, we managed to get
away with SHS80, except where we needed
to support the gutter, we had to increase
four of the main columns to 152UCx30,”
Granicki explains.
More than a roof
AOJ redesigned a simply supported roof
and supports from a lattice truss structure
averaging 44kg per m 2 (40 tons over 900m 2 )
to a floating structure that averages 35kg
per m 2 without unwanted supports.
The steel roof overhangs helped design
a passively cool home which mitigates heat
gain by shading the exteriors throughout
the day in an area of the country that often
reaches 30 degrees Celsius in winter and
well over 40°C in summer.
In the interior, huge glass windows,
doors and fin walls constantly connect and
direct the user to the outside bush. The
placement of the windows facilitates a
constant flood of light on the hand polished
concrete floors and simple plaster walls,
while angled ceilings facilitate natural
airflows and complement other sustainable
features of the project (such as rainwater
harvesting from the extensive roof structure).
“As the client comes from a mining
background, aesthetically the home reflects
a ‘from the earth’ narrative and an almost
industrial approach is embraced using
crushed rock, gabion walls and steel
I-beams,” explains Granicki.
Overall look
In this private lodge at Mjejane Private
Game Reserve, the architects have created