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Raft Foundations

Raft Foundations are designed to be an economic alternative to the TC3 surface structures outlined in MBIE Technical Guidance 2012.
How it’s done

Raft Foundations use MultiPole UniLog beams to form a lattice of strong, lightweight foundation beams. This ‘raft’ is designed to have a four metre internal span and a two metre cantilever at the edge, should your building lose ground support.

We’ll install your raft using a small, 5 tonne digger. There’ll be minimal ground loading and excavation required, with any materials we do excavate being placed back in-between beams and compacted.

If you’re planning on having a concrete slab, we’ll place a working platform of hardfill between the beams. For a timber floor, we’ll fix pre-scalloped UniLog jack studs at the intersections of beams to support timber bearers.

Benefits of this system

•  Installation time frame subject to the size of the poles and the quantity and ground conditions.

•  Lightweight – suitable for ground with ultimate bearing capacity of 100kPa or less with specific design.

•  Able to be designed for more than 300mm of lateral movement.

•  Timber floors are able to be re-levelled following seismic events.

•  Concrete floors can be re-levelled using cast-in jacking screws.

•  Uses award-winning MultiPoles.

•  PS1, PS3 and PS4 provided.

Additional specific design options

With specific design work sites with exceptionally poor ground conditions, such as SLS Index settlements greater than 200mm, ground with larger than 500mm lateral stretch, or 30kPa ground, can still utilise a Raft Foundation.

Raft Foundations can be combined with additional foundation solutions, such as Ground Improvement or Deep Piles, to provide a site specific foundation solution.

Quick reference information
Technical category Type of MultiPole used Typical pole diameter Typical pole length Typical pole spacing Typical installation method
Residential foundations TC2 & TC3 UniLog 275mm for beams and 180mm for jack studs To suit house dimensions 1.0–4.0m 5 tonne excavator
Commercial foundations TC1, 2, 3 UniLog 275mm for beams and 180mm for jack studs To suit building dimensions 1.0–4.0m 5 tonne excavator
Road foundations TC1, 2, 3 UniLog 275mm for beams and 180mm for jack studs To suit building dimensions 1.0–4.0m 5 tonne excavator
  • Compare quick reference information

    Foundation system Technical Category Type(s) of MultiPole used Typical pole diameter Typical pole length Typical pole spacing Typical installation method
    Deep Pile Foundations Residential foundations TC2 & TC3 SED, Uglie, UniLog 150–250mm 1.0–22.0m Poles can be joined to reach greater depths 2.0–4.0m High frequency vibration and pile driving
    Commercial foundations TC2 & TC3 SED, Uglie, UniLog 250–300mm 1.0–22.0m Poles can be joined to reach greater depths 2.0–4.0m High frequency vibration and pile driving
    Ground Improvement Residential foundations TC2 & TC3 Uglie 200–300mm 2.4–4.8m 1.0–1.5m High frequency vibration and pile driving
    Commercial foundations TC2 & TC3 Uglie 300mm 6.0–15.0m 1.0–2.5m High frequency vibration and pile driving
    Raft Foundations Residential foundations TC2 & TC3 UniLog 275mm for beams and 180mm for jack studs To suit house dimensions 1.0–4.0m 5 tonne excavator
    Commercial foundations TC1, 2, 3 UniLog 275mm for beams and 180mm for jack studs To suit building dimensions 1.0–4.0m 5 tonne excavator
    Road foundations TC1, 2, 3 UniLog 275mm for beams and 180mm for jack studs To suit building dimensions 1.0–4.0m 5 tonne excavator

Find out more about the Raft Foundation system

It’s just a few, easy steps toward a strong foundation

1

2

3

Geotechnical report

Site-specific design

Site visit and installation

First of all, we’ll need a geotechnical report for your site. If you don’t have one of these, we’ll help you get one.

This will be based on your geotechnical report, and could involve the customisation of one or more of our existing foundation systems.

Our installation processes are fast and efficient. They’ll have minimal impact on neighbouring properties and will leave your site undamaged.

4

Sign off

Issuance of PS3 and PS4 documentation.

You now have excellent foundations to build on!

START THE PROCESS TODAY

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