Many Australian cities have hilly areas, and where you have hills you have sloping blocks. The methods used by Volume Builders are not good solutions for these potentially beautiful blocks. Either they refuse to build on them or they charge the earth for site costs, dig a hole in the block and bury a house in it. Yet there are quality custom builders who have specialist knowledge in the challenges and potential solutions for building on hilly blocks, and can provide cost-effective solutions. Here are a few design options to keep in mind when building on a sloping block.
Blocks that rise from the road: If a block rises up from the road, the most efficient design may incorporate a garage underneath and the house built above. And if you’re placing a garage underneath, why not another room as well? This is an ideal location for a theatre or rumpus room or a study; areas to be quiet, or to be noisy without interfering with the remainder of the house. Living areas are built above, and your open plan kitchen or family room can open out to the rear of the house on ground level. With appropriate landscaping, you maximise the enjoyment of your yard.
It is common to consider a balcony at the front of the house over the garage, so people can have breakfast and admire the view. However, these areas tend to be used very little in real life because they do not have privacy. In suburban locations a balcony is mainly for looks. A good solution is to put in a much smaller balcony which creates an attractive street-front – and the option of popping out to see a sunset. Or you can go with a decorative balustrade as a façade feature without the expense of waterproof balconies. This could save you $10,000 in costs.
Blocks That Fall From The Road: Where a block falls away from the road, it is often a good solution to use a split slab foundation. The front of the home will be at street level, with the garage on one side, and a lounge room, master bedroom and entry hall at the same level. You would go down a number of steps to the next level, following the contour of the block.
If a client wishes to utilise a timber subfloor, they should consider two storeys at the rear of the house. The front part of the house that faces the street will be a single-storey, but the inevitable space beneath the house to the rear will be incorporated as a rumpus room or laundry or study.
Split Slab or Timber Sub-Floor? Many people think that the only way to build on a sloping or hilly block is a timber subfloor. However, there are different solutions, with different advantages.
Historically when building on a timber subfloor, the whole floor area is lifted up to one level, creating a house that is high out of the ground. The base of the house is built up with brickwork, creating a lot of under-utilised space. In a modern home, this area should be incorporated into the whole design as a functional lower storey.
Building on a concrete slab reverses the process. The block is excavated to create a surface suitable for a concrete slab. You eliminate the base brickwork, and only provide framework and brickwork above floor level. This reduces cost. Timber subfloors are generally more expensive, however there’s a point where one will override the other, depending on the amount of space required, and degree of slope. On a block where you have a slope of anything up to 1 ½ to 2 metres, a split concrete slab will be cheaper.
A slab also has advantages with respect to thermal qualities, as well as energy rating and BAL (Bushfire Attack Level) rating.
Blocks that slope to the side: Side sloping blocks are a different kettle of fish. Each block will need to be looked at individually. It may still be viable to use a split slab, and obtain an economical and practical solution. If you have the budget, a timber subfloor is likely to be the best solution.
As long as you’re excavating… Remember that your home doesn’t stop at the walls, it encompasses your garden and surrounds. Landscaping will be a big part of making your home a great place to be. Incorporate this into your overall design, and while you’ve got a big machine on site to excavate foundations, have them do the overall external landscaping too. You’ll save yourself time and money, and when you get the key to your house, you’ll be well on your way to enjoying a real home on your lovely hilly land.