google-site-verification=pWL-tsKv_tSQTqlhcmJpCmxpK3cFODQyFtvPX7fxHG8 Steep sites
  • James Brokenshire

Steep sites

Updated: Aug 2, 2018

A steep building site generally has gradients exceeding 20 degrees, however even a 1V:4H, (14 ) slope should assessed for ground stability. If you are looking at developing a site which is considered steep it is important to have it reviewed by a geotechnical engineer who can assess that the site is stable, explain design options as well as potential obstacles to develop the site.


You might have a large land area, however for steep sites the area that can be built on may be constraining.


Steep sites require proper consideration of site slope, ground condition, site access, building platform location and size. It may be preferable not build on a steep site due to the additional costs. On the other hand, steep challenging sites often come cheaper, come with views and can be exciting places to live.


Very steep sites often pose a physical constraint on the type and form of the house than can be built. Foundations for steep sites are often best suited to pole framed type houses, and it is recommended that the development tries to minimise the amount of cut and fill needed to accommodate the development.


Other recommendations to reduce the need for cuts is to build along the contour.


However, challenging sites may prevent easy access for vehicles and pedestrians. On sloping sites, steep driveways or large volumes of cut and fill may be the only solutions.


Ground conditions


Ground conditions influence the type of foundations and allowable disturbances to the site.


Different soil conditions and location, such as rock, sand, or Seacliff’s place different constraints on design requirements.


The costs of mitigating existing ground conditions which are considered unstable can create large cost overruns and design challenges, so early identification is critical for effective site planning and later construction work.


If you are looking at developing a site which is considered steep it is important to have it reviewed by a geotechnical engineer who can assess that the site is stable, explain design options as well as potential obstacles to develop the site.


These sites are not for the faint hearted, proceed with caution. I have personally been involved with several sites where our Client engaged our services after already buying the land, only to find out they have paid too much money for marginal land, requiring expensive engineering stabilising works. The land looked amazing to our Clients eye but clear trouble to us.


Geomorphology, soils topography, history of landslips in the area, the presence of landslip debris or landslip scars, high water tables, and poor drainage are just some of the issues that can be picked up by an experienced geotechnical engineer.




​Feel free to contact us now to discuss all your geotechnical needs with a no obligation project scoping and quote.

https://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10530966

https://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=11917337

https://www.nzherald.co.nz/property/news/article.cfm?c_id=8&objectid=10529874

https://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10526194

0 views

Shire Geotechnics Ltd     /  Auckland /  info@shiregeotechnics.co.nz

Ground Testing