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Cost of building into basement in Sydney?

8 years ago

I'm hoping to excavate a 35sqm basement by an additional 1m so that it can become usable floor space). Has anyone in Northern Sydney built into their basement, making use of a sloping site? If you have, are you able to provide a rough idea of what it cost per sqm and companies that do this?

I previously lived in London where creating space in the basement is common with many builders specialising in it - but I haven't seen anything like it here

http://www.londonbasement.co.uk/portfolio

Many thanks!

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Comment (1)

wetlock
8 years ago
Hi. For Northern Sydney, the biggest variable is the excavation costs. Particularly if you hit rock/sandstone which is quite common. Most excavation companies won't give you a firm quote as you just don't know what you're up against.

You will need to factor in the concrete slab, plumbing, blockwork walls and waterproofing. They use a product called John Newton in the UK so that you can waterproof from the inside - particularly useful if you have zero boundary you want to work to. Prices will vary significantly, depending on what finishes you want.

You're correct in saying that most builders won't do it here and that's primarily due to a lack of experience with it - especially from a waterproofing point of view.

Try contacting Marshal Keen who is based in Sydney. We've worked with him previously with these types of projects and he's brilliant!

www.marshalkeen.com.au
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