Technical notes on The House of Steel

The soil where we are building is known as expansion clay. When it dries it shrinks a lot and when it's wet it swells up. The early settlers knew this and usually built their masonry houses on rubble foundations that cope well with this condition (for the last 150 years or so anyway). Modern building regulations do not allow rubble foundations, so masonry houses are built on concrete slabs that respond to the expansion and contraction of the clay by cracking. Making the slabs ever thicker with ever more steel reinforcement doesn't seem to help as the droughts get droughtier and the wet periods get wetter.

We didn't like this idea much, so we elected to build a flexible house that would cope better with the clay. The House of Steel is to be built on piers that are concrete cylinders 2 metres deep and 450 mm in diameter. From the concrete to the level of the floors, are steel pipes 90 mm in diameter supporting steel beams 180 mm deep. The floor joists are timber 180 mm deep and the walls are conventional balloon framing using 90 x 45 mm hardwood. The roof is supported by 100 mm steel purlins.

The cladding is corrugated sheet steel coated with zincalume. I reroofed the cottage with this material 18 years ago and it has yet to show any deterioration. Low maintenance is a high priority for us. While zincalume is available prepainted, the paint layer is easily damaged during construction. Leaving the steel to weather for a year or two, then painting with a high quality exterior paint will do a better job anyway.

Northern Elevation

Note that since we are in the southern hemisphere, North is where our sunlight comes from.

Internally, the floors will be exposed varnished floorboards made out of local hardwood. This is very attractive, hardwearing and easy to clean. We may buy some rugs down the track. The kitchen part of the living area will be black Italian tile. The laundry and bathroom floors will be covered with sheet vinyl.

The built in cabinetry will be finished with laminate in two colours. A patterned black on work surfaces and a blue/grey on cabinet faces. Splashbacks will be brushed stainless steel.

Walls and ceilings are all sheetrock and are to be painted white.

The windows and external doors are all double-glazed and vinyl framed for thermal efficiency and low maintenance.

Insulation of walls, ceilings and floors is to be tontine, a synthetic non-irritant fibre. I'd be happy enough to go with fibreglass since once it is in place, it's sealed away completely. However, I have been told the price difference is negated by the extra care needed with gloves, mask, etc when handling fibreglass.

The house is designed for our lifestyle and our needs. We cook and space heat with a wood burning cookstove. It supplies sufficient heat to supply hot water needs as well as run five hot water radiators. The cookstove was our first purchase for the house a couple of years ago. We had decided we wanted a Bosky and found a second hand one saving several thousand dollars.

The house is a small one by American standards and about average by local standards being some 14 square metres (1500 square feet). I nearly achieved my aim of getting what we wanted in 1400 square feet. Rattling around in and having to clean huge areas was of no interest to us whatsoever.

Floor plan

The living/dining/kitchen area is combined as we entertain informally. Marguerite and I both enjoy cooking for our guests as well as each other. The kitchen bench area is generous enough for half a dozen cooks should the need arise.

The master bedroom is no larger than it needs to be and the bath is in the adjoining ensuite because I much prefer baths to showers. The laundry doubles as the "public" bathroom and has the shower.

The second bedroom is our son, Thomas's. He is a teenager and we included an external door so he can come and go as he pleases when that time comes. It is generous enough in size that he can have a friend bring by a computer for LAN games.

What would usually be the 3rd bedroom is my office and I will have room for all of my computers and other stuff.

The unusual valley roof needs some comment. We will collect the rainwater in the 4,500 litre water tank at the front of the house and pump that into a supply tank of 23,500 litres on an elevation behind the house. Most people use an electrical pump that starts on demand when a tap is turned on. The problem with that is you have to go without water if the electricity supply fails. I prefer to rely on gravity to supply the water to the household. The valley gutter cannot and will not flood up into the house unless we get our annual rainfall in less than a day. The closest we ever got to that was our annual rainfall in a month! The gutter can be easily cleaned by walking down it with a yard broom.


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TC Jonathan Sturm 2000 - 2011

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