Granny flat report
Site classification and soil reports for granny flats and secondary dwellings
The AS 2870 classification a secondary dwelling needs before the slab can be designed, priced the same as a house.
A granny flat is a house in miniature as far as the ground is concerned: it needs a slab or footing designed for the soil under it, and that starts with a site classification. Because the flat is usually at the back of the block, sometimes over old fill, a pool that was filled in, or a large tree, the classification matters more than people expect.
The fee is the same standard site classification fee: a field engineer, two boreholes where the flat is going, laboratory testing where needed and a signed AS 2870 report. If access to the back yard is tight we bring hand equipment.
What you get
What the report includes
- Two boreholes at the location of the secondary dwelling
- Soil profile logged and classified to AS 1726
- AS 2870 site class with the reasoning
- Notes on fill, trees and drainage that affect the slab
- Signed report for the slab designer and certifier
Who it is for
Typical jobs
- Owners adding a granny flat, studio or secondary dwelling
- Granny flat builders who need a classification for every job
- Designers lodging a complying development certificate
Further reading
Before you order
How it works
Three steps from your address to a signed report
Tell us the address
Send the site address and what you are building. Standard sites get the fixed fee straight away; anything else gets a scoped quote before we book.
A field engineer drills the block
We come out with a rig or hand equipment, drill the boreholes, log the soil as it comes out of the ground and take samples for the laboratory where the report needs them.
A signed report lands in your inbox
A geotechnical engineer checks and signs the report. It goes to you as a PDF, ready for your builder, slab designer or certifier.
Sydney site classifications: 5 business days or free
Five business days, or the report is free
A site classification in Sydney is finished within five business days of you accepting the quote, or you don't pay for it. All we ask is that we can get onto the block.
Need it sooner? Three business days or less for $300 + GST.
What the guarantee assumes
- It covers a standard site classification. Geotechnical reports, investigations and retaining-wall work are scoped site by site and get a timeframe with the quote instead.
- The site is in the Sydney metropolitan area — the Sydney Metro zone on the pricing page. Other zones get a timeframe with the quote too.
- The five business days run from when you accept the quote. Business days are Monday to Friday, excluding NSW public holidays.
- We can get onto the site. If access is not available on the day we book, or we are turned away, the clock pauses until we can drill.
- The invoice is paid before the site visit, as it is on every job. Days an invoice is outstanding are not counted.
- The scope is the one you accepted. If the ground turns out to need more holes, deeper holes or extra laboratory testing, we quote that first and the clock restarts when you accept it.
- If we miss it, the report is free: we do not invoice it, and where it has already been paid we refund it.
The full wording is in the service terms.
Questions
Questions about granny flat reports
- Is it the same report as for a house?
- Yes. AS 2870 does not distinguish between a house and a secondary dwelling; the footing is designed the same way, from the same classification.
- Can you get a rig into a back yard?
- Usually, with a small rig through a side gate. Where that is not possible we use hand auger and DCP equipment, which is enough for a classification on most sites.
Need a granny flat report?
Send the site address and what you are building. Standard sites get the fixed fee straight away; anything else gets a scoped quote before we book.