Building Standards: Foundations

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If you're having your own house built you'll need a soil test, and an engineer to determine the type of foundations required. A local engineer (or architect) may be familiar enough with the locale so that the test is just to confirm. Usually a trial hole is dug to see what's below ground.

If you're buying from a developer then it's good to know what's happening below your house. As the building will probably be a concrete frame, then the foundations will be piled. I haven't come across raft foundations here but then maybe someone can post on this.

Piles are driven into the ground for 10 or 15 feet depending on the support capacity of the soil. There's really not much difference between one, two or three storey houses. The piles are pre-cast concrete with metal ends. Once in place a concrete pile cap is cast with 4 reinforcement bars sticking out vertically to form the column. Before the columns are cast, a system of ground beams is constructed. The space between the ground beams is then filled with levelled soil, and the concrete ground floors are constructed.

There's little skill involved in this as it's all pretty basic. Plywood sheets are used for the concrete shuttering. The steel reinforcement bars used are always rusty but the cement is alkaline and this inhibits rust growth so it doesn't really matter.

Here's are some photos to show the (1) piling machine (2) assorted piles (3) pile cap (4) ground beams for a 3-storey house.

Scott

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Of course, the other way to build foundations is to follow the local traditional building form and, more or less, just plonk a timber column onto a stone, concrete or brick base. Some such buildings have been around for many, many years. A modern tile roof is going to add some weight, as will modern fittings/furnishings but I can't see that the extra loading would be too much.

The elegant house in the first 2 photos is over 100 years old. The house in the 3rd photo needs some attention but it's been around for some time with just a couple of layers of bricks for the foundations. The last photo is a timber framed 1940's government staff unit sitting on brickwork piers and timber beams.

One big advantage here is that if you don't like the neighbours you can move and take the house with you.

Scott