Residential Extensions in Penshurst - What do you need to be aware of with sloped lands?

When you have a land that is on a 'slant' from the front to the rear, there are a few things that you will need to be aware of, especially if it comes to planning a residential extension or building a new home. A qualified residential designer should be able to highlight these "limitations" or "expenses" that you may not know prior. Don't get me wrong, sloped lands are still great for home projects. Anything is do-able, really!

Yet, it just comes down to knowledge and cost, and know what you are paying.

1. Slope lands require extra cost on labour.

Slant lands bring difficulties for trucks and builders to move materials around effectively, both in and out of the building. Considering the extra energy , time and effort required, the cost of the whole project may be about 20% more (this is to cover the labour).

2. If there's no separate easement, your builder may need to pump the rainwater to the front street, against gravity.

In Sydney, a lot of councils refuse rainwater to be discharged into the main board sewer (or what we called the Sydney Water's Sewer), instead it is highly recommended that it should be discharged into a 'separate easement (SE)' (owned by the council). Though, not all domestic homes have a SE. Hence, your hydraulics engineer may suggest installing a pumping system which charges the water to the main street (against gravity). This pumping system costs about $30,000 extra.

3. A geotechnical report helps identify the feasibility.

When a pumping system is required, councils may request a geotechnical report which assess the land and the soil by taking samples of the ground for lab tests. A geotechnical engineers (a.k.a "mud-experts") assess the materials underneath the ground to provide recommendations of its suitability for hydraulics pit/well design. A geotechnical report can range from $800 - $3000 depending on the complexity of the land. 

4. You may be asked for a OSD from the hydraulics engineers.

An OSD (On-site detention) is a system designed by your hydraulic engineer which explains how the rain falls on a site (known as stormwater), storing it temporarily and then releasing it slowly so that it doesn't worsen downstream flooding.

5. I have a sloped land, from rear to front of the street, do these problems apply?

Not necessarily, it depends on the type of system it is currently used on the site. Councils encourage rainwater to be flowing to fall to the main street. Given that your land is sloping from the rear to the front. It may indeed be a simplier job!

6. I have a sloped land, from front to rear, what should I do if I want to extend the house?

Check with a qualified residential drafting and design team, speak to them and understand what you need to do, so you are prepared for the cost involved. Don't blind-sign any contracts as there may be hidden costs if you did not understand it carefully.