HOUSE OF STEEL AND GLASS



While not conventionally alternative (if that’s not a contradiction in terms) Collyn’s Broome house is environment-friendly and respects the traditional owners’ sites of significance. It uses modern materials and techniques resulting in a pleasant living space sitting well in a beautiful site.

Our home at Ngungnunkurukan, 20 kilometres north of Broome, is a very special place. The site adjoins one of the three major Aboriginal song lines that traverse Australia. It has major rock formations that are significant to the local Gularabulu people, whose community is a kilometre or two south. The land is ten acres of natural bush and fronts directly onto a tidal lagoon and then the Indian Ocean about 400 metres to the west.

It has been agreed with the traditional owners that all rocks and significant trees are left untouched and that we do not allow access to an exceptionally sacred part of the site. Also, as far as possible, we avoid having any heavy earth moving machinery close to that area. The Shire and FESA have also been cooperative in allowing obligatory fire trails
to detour away from these areas. As with all of the area there are no shire services excepting part dirt road access. We bought the land in 1998 and moved onto it in April 2000. Broome’s worst cyclone for half a century (Cyclone Rosita) struck ten days later. We sheltered from the 160-kilometres- an-hour gusts by burying our OKA off-road truck to its axles and strapping a table over its windscreen. In retrospect it was an invaluable introduction. It caused us to rethink the engineering overnight!

Our main requirements were for light and space, plus a home that would form a natural extension of the Indian Ocean and dunes to our west, and the bush behind us. The original design and engineering was done in Brisbane. The concept was fine but (as an engineer myself) it was no surprise that the original engineering was twice rejected (by Broome Shire) as totally inadequate for cyclone protection. It was subsequently and brilliantly re-done by Garry Bartlett of B&J Building Consultants (in Broome). The resultant drawings took up over 60 A1 pages.

In many ways the resultant structure is closer to a steel bridge than a house. Unlike most self-built homes it is essentially a hi-tech structure using structural engineering rather than building techniques. There is not a single mud brick, straw bale or piece of timber in it!

Pouring the main concrete slab. Almost a military operation! The more than 40 tie-downs had to be placed within three millimetres in all planes. The perimeter concrete beams are 600 by 600 mm and the floor is 200-250 mm thick.

The structure is essentially an immensely strong double curvature roof tied down by forty 100 by 100 mm square hollow steel posts into a 600 by 600 mm concrete perimeter beam. Diagonal 120-mm steel tubes, extending into 650 mm diameter by two or three metre- long buried concrete cylinders, provide further support. The roof itself is of heavy gauge Colorbond secured by 14 gauge Tek screws and cyclone washers at every channel into purlins that are welded to four similarly double curved rolled steel joists. A similar gauge terracotta-coloured ceiling is attached directly to the underside of the purlins.

The remainder of the house is almost entirely stainless steel security mesh sliding doors and cyclone-proof toughened glass sliding doors. There are no internal walls as such. The first major building problem was having the originally planned 100 by 200 mm rolled steel section roof supports rolled to the necessary double curvature (without buckling). This proved to be impossible and the design was changed to similar sized rolled steel joists. These were rolled up in Perth and trucked the 2100 km to Broome. There the beams were welded up into complete end sections and trucked the 4200 km round journey to and from Perth for galvanizing. Meanwhile the roofing sections were rolled to the same curvature.

The second major problem was that the all-steel structure called for dimensional tolerances of only a few millimetres. This is close to watch making compared to the building industry’s more typical plus or minus a centimetre or two (or the Kimberley builders’ plus or minus one postcode). The 600 mm perimeter beam had over 40 beam tie downs, all of which needed placing within two to three millimetres in all planes. Surprisingly, it worked out. The final 150-square-metre main structure measured within five millimetres across the diagonals.

The steel suppliers erected the steel structure — assisted by a 200-tonne crane ‘borrowed’ for the day. Even at 200 tonne capacity that crane worked hard, having to position 1100 kg steel beams at its full extension of close to 50 metres. Contractors were used for concreting, roofing and internal plumbing but, apart from that, all the work was done by ourselves — with the invaluable assistance of an ex builder who was living locally at the time.

Power for building was supplied almost entirely by solar. I built a 28-module system prior to starting the main construction and this provided 4 kW, and up to 11 kW surge. It could and did drive multiple nine-inch angle grinders. This, more even than the house design, tossed the contractors. Being locals they knew there was no mains power. Yet
here was 240 volts at considerable wattage — and no generator. It never was possible to persuade them it really was solar. We finally ‘confessed’ that Western Power trucked in a load of watts each morning. The task was eased by my being an (ex) engineer — albeit of the research variety.

My now-psychologist and somewhat feisty wife, Maarit, has a sculpting background, and had acquired Welding and Production Engineering Certificates at Broome TAFE in anticipation of building. She was and still is very much at home with big power tools (like nine-inch angle grinders). Heaven help any tradesman or sales person who makes the considerable error of patronising her in the local hardware store!

Maarit does a heavy blacksmith job on a roof tie-down plate (she has a ‘do not mess with me’ reputation amongst tradesmen in Broome!).	Plan and elevation of Collyn and Maarit's house (click here for a larger image)

We started building in earnest in August 2000 and moved into the semi-completed house just before Christmas that year. It was reasonably finished by April 2001. Unusually for the Kimberley, the main house runs year-round on rainwater — even for toilet flushing. The house’s 280-squaremetre roof has two 250 mm by 150 mm stainless steel gutters inset between the roof and the ceiling (for cyclone protection). Water flows via the diagonal bracing of hollow 120- mm steel tubes to a pair of 150-mm pipes. These tee into sunken 200-mm pipes that run the full length of both sides of the house to fill a 14,250-litre holding tank behind and north of the house. This tank catches the torrential rain that accompanies passing cyclones. It can fill in less than one hour. The water is then pumped up to coupled 100,000-litre and 21,500-litre tanks about 100 metres from the house, and on the same level. It is supplied to the house by a pressure pump backed up by a 500-litre water pressure tank. In practice the water is supplied by that tank’s air pressure. The pump replenishes the pressure tank once or twice a day. This has proved to be an extraordinarily efficient way of pumping water. The bog standard 0.75 kW pump runs just twice a day for about three minutes each time.

Kitchen with a view	Walls of glass bring the outside in.

An above-ground rendered concrete block 31,000-litre swimming pool is attached to the house. This, as with all of the house and property, runs from solar alone. It has an interesting and originally unique way of operating that is fully described in the December 2007 edition of Earth Garden. Briefly, the pool has its own 480- watt solar array that drives a Lorentz 48-volt brushless DC motor pump. Rather than using a lot of chloride, the irrigation water feed was diverted to pass through the pool. That water is pumped from our bore and is unusual in being crystal clear and totally taste free. It must be some of the purest water in the world. It comes from the Leopold Ranges some 500 km north-west of Broome (with untouched land between the two). We only use about two per cent of our annual allocation. The unused remainder pours into the Indian Ocean.

Easy clean bathroom

Sewerage at present is septic. We would have preferred a more ecologically sound system but the then Shire regulations prevented this. We had nothing but genuinely helpful cooperation from Broome Shire throughout. They rejected the original engineering plans but I had already felt they had no chance of meeting cyclone requirements and welcomed their comments. Once the plans were redrawn, Broome Shire’s planning, building and health departments were thoroughly supportive throughout. Our kitchen was built by a local company but the standard of workmanship was dreadful. My wife told one of the employees “call yourself a cabinet maker — you are not even a half decent bush carpenter”. The house works well. There are a few things we intend to change that were mainly brought about by our change in lifestyle since moving here. This was to be a place to settle down but certainly not to retire. Since 2000, I’ve written and published five books and am about to publish a major book on solar. I also spent three years at Notre Dame University auditing the Aboriginal Studies course. Meanwhile Maarit acquired two degrees (also from Notre Dame), and added some Spanish and Mandarin to her previous four languages. We enjoyed building the house, but would not do it again!