Reading a block before you buy it

Fall

The single biggest cost driver on most blocks. A level site takes a slab. A falling site takes excavation, retaining, drop-edge beams or piers, and often a stepped design — all before you have built any more house than the flat block would have given you.

Fall is not automatically bad. A well-handled slope gives you an undercroft garage, a lower floor that opens to the garden, and a house with a view over its neighbours. It is only bad when nobody priced it before the land was bought.

Walk the block. If one corner is obviously higher than another, get a contour survey before you commit.

Aspect

Where north is decides how the house will feel for the next forty years, and it cannot be changed later at any price. In Sydney you want living areas and the main outdoor space facing roughly north, so they take winter sun and can be shaded in summer.

A south-facing rear yard is workable, but it needs deliberate design — clerestory glazing, a courtyard, a rethink of where the living rooms go. Know it before you buy, not after.

What is under it

Soil classification governs your footings, and the difference between a stable site and a highly reactive clay one is real money. Rock is the other surprise: it is invisible from the surface and expensive to remove.

You cannot know either for certain without testing, which is why excavation is so often a provisional sum. What you can do is ask the neighbours what they hit, and look at what the houses either side are founded on.

What the title says you cannot do

• Easements give someone else rights over part of your land — usually drainage or sewer. You generally cannot build over one.
• Sewer lines can run through the middle of a block. Building near or over one means a build-over application and possibly piering.
• Covenants and restrictions can dictate materials, roof pitch, minimum floor area or where the house may sit.

Ask for a copy of the title, the deposited plan, a sewer service diagram from the water authority, and the planning certificate for the property from the council. Your conveyancer will normally obtain these; read them rather than filing them.

Setbacks, envelope and what will actually fit

Councils set how close to each boundary you may build, how high you may go, and often a sloping envelope from the side boundaries. Two blocks of identical area can take very different houses once the envelope is drawn on.

Before you buy, sketch the footprint you want inside the setbacks. If it only fits by ignoring them, you are relying on a variation the council does not have to give you.

Trees, access and services

A protected tree can take a third of your buildable area with its root zone, and removal is the council’s decision, not yours. Ask what is protected before you plan around it.

Access matters more than people expect. A concrete truck, a crane and a waste bin all have to reach the site. A narrow frontage, a steep driveway or a battle-axe handle can add real cost to every trade.

Finally, check that power, water, sewer, gas and telecommunications are actually at the boundary. Bringing a service in from the street is a line item nobody enjoys discovering late.

Overlays

Bushfire, flood and heritage controls change what you are allowed to build and what it must be built from. A bushfire attack level rating drives window, cladding and screening requirements that can move a budget significantly.

These sit on the council’s planning certificate. If any of them apply, get advice specific to the block before you bid on it.