Fall is a reference to how much slope or gradient is on your block. Most builders are looking for less than 1m of fall across your site. This is generally measured diagonally across the building line from corner to corner, taking the highest point as the reference point.
Cut & Fill
When the developer is constructing the allotments, they are looking for the flattest line possible across the entire development. This can mean that some sections of the development have excavation (cut) and others have additional soil laid on top of them (fill). Depending on where your block fits in the development, this can have dramatic effects on your site works costs, as the builder requires dense soil to lay the new home slab and a flat block to do it on.
Before the builder begins construction on your lot, they will engage an engineer for a soil & survey report. The engineer will drill a test hole on your site to see what lays beneath. If the test shows a rock bed under your block, there may be additional costs added for the rock removal. They will also test the density (or compaction) of the soil to see if additional concrete piers are required.
Avoid them. Trees onsite (and even trees that have previously been removed from site) leave a root bed. This means that additional piering (deeper concrete pylons) are generally required in and around the tree site to make sure the house doesn’t move as the roots grown, die or change.
Easements (and not just yours!)
Easements run across or adjacent to most blocks. This is where the developer runs your services such as sewer and water. You can’t legally build over an easement (as access is required in the event of a fault and also that it isn’t structurally sound) which means that your house has to be a minimum distance away from the easement lines. Building within a certain distance of an easement can incur additional costs, as piering will need to be done to ensure the home doesn’t move or slide toward the easement.
Be aware that easements on the lots next to or behind yours can also affect your site works if they are too close to your home.
In some cases, where the block has a significant amount of fall, the developer may choose to batter the block to keep the house pad as flat as possible - meaning the large section of the lot is flat and the front, side or rear of the block may have an extreme incline. There are additional costs that can be incurred if the home is too close to the batter line to ensure its secure. Batter will also affect your landscaping requirements (and costs).
Like batter, the developer is looking for a flat building surface across the middle of the lot to assist the builder. If the lot is at the low side of adjoining allotments, it may require a retaining wall to secure the dirt from the block next door. Builders will want to add additional concrete on the retaining wall side to make sure, even if the earth moves, the house won’t.
Luckily, most builders will offer a ‘fixed’ site cost amount. The fixed amount means that the builder underwrites the site works cost. For the consumer, this means certainty: that even if the builder uncovers further works required – such as unforeseen rock removal - you won’t be charged another dollar. It’s a calculated risk on the part of the builder based on a thorough reading of your site engineering drawings, receiving a level 1 compaction report from your developer (which tests the reactivity of the soil on site) as well as an understanding of previous homes they’ve built in the estate or neighbouring estates. Be sure to read the fine print – as not all builders cover all instances when it comes to additional costs.
Wherever possible it’s best for a customer to look for a fixed site cost amount. And, provided your home isn’t built on the side of a cliff with a huge amount of top- soil, your builder should offer this as an option