Foundation Design Northland
Told your site needs specific foundation design? Gumboots designs foundations for Northland's expansive clays, soft ground and sloping sites, with producer statements for your building consent.
When You Need Specific Foundation Design
Standard house foundations under NZS 3604 only apply on "good ground". When a site has expansive clay, soft or variable soils, fill or a slope, council needs a foundation designed by an engineer.
- Expansive (reactive) clay
- Soft, wet or variable ground
- Uncontrolled fill
- Sloping sites, or building close to a slope
- Heavy or unusual structures
The same applies to a granny flat or minor dwelling on difficult ground. Our planning partner Far North Resource Consents handles the granny flat consent.
Foundation Types We Design
Raft and Rib Slabs
Stiffened concrete slabs that ride out ground movement on expansive clay sites.
Piled Foundations
Timber, concrete or screw piles taken down to firmer ground.
Deepened Footings
Strip and pad footings taken below the zone of seasonal clay movement.
Pole Platforms
For steep sites where a level platform would need large cuts.
How It Works
Geotechnical Investigation
We test the ground and classify the site. See our geotechnical reports.
Foundation Design
Drawings, calculations and specifications for your builder and council.
PS1 Design Statement
Our producer statement for the design, lodged with your building consent.
Construction Review and PS4
We inspect key stages on site and sign off with a PS4.
Northland Ground Conditions
Northland's weathered clays often have good bearing capacity when dry but swell and shrink as they wet and dry. Around Kerikeri, basalt ground can vary sharply in depth to rock. Good foundation design starts with knowing which you are building on.
Get Your Foundation Designed
Send us your plans and site address. We will tell you what testing and design your site needs and give you a fixed quote.
Based In
Kerikeri, Northland
Serving all of Northland