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RibRaft Waffle floating foundations
Concrete and polystyrene foundation construction

Becoming one of the fastest growing residential and light commercial flooring options in New Zealand, the Firth RibRaft system is an innovative solution for concrete flooring construction.

This fast, efficient and practical construction method is designed by our engineers and installed by our approved team, and will save time and provide high strength and durability.

Using polystyrene pods, plastic spacers, steel reinforcing pods and RaftMix concrete, these components help to dramatically reduce labour and time used compared to traditional concrete foundations.

From small homes to large developments, this versatile system adapts perfectly to a range of projects.

For a free RibRaft concrete foundation quote, please fill out the form to the right.

Our team are also installers of Cupoflex foundations and underfloor heating options.

More information on RIBRAFT concrete waffle foundations below the image gallery

What are the advantages of RIBRAFT foundations?

Efficient installation - reduced build time
There is no need to dig trenches for footings with the RibRaft system, resulting in dramatic reduction in both labour and time. All of the foundation construction occurs above the ground, and construction can continue as per normal throughout wet weather.

Highly insulated, energy efficient floors
There are a number of insulation benefits from installing RibRaft floor, such as excellent thermal efficiency.  

Strength and stability
With a highly increased strength and resistance to cracks, this system can be built on soils with a pressure as low as 50KPA. The concrete slab has immense strength, as it is reinforced with a concrete perimeter beam and concrete ribs over the floors.

Reduced waste on the building site
There is a great reduction in excavated material on your construction site as the floor is 'on ground' as oppose to 'in ground'.

Install underfloor heating with your new concrete foundations

Underfloor insulation is ideal for keeping your home warmer in the colder seasons, and the RibRaft system is perfect for easily integrating underfloor heating into your home.

For more information, visit the underfloor heating page.

Installing RIBRAFT concrete waffle foundations

Step One

The building platform is cut to level the surface approximately 330mm below the finished floor level.

Before slab construction commences, the Council will need to inspect the site.

Step Two

A layer of sand (up to 50mm thick) is placed over the entire building area, extending 1m outside the perimetre.

If necessary, key piles are constructed at this stage.

Step Three

Damp proof membrane (with a minimum thickness of 0.25mm) is laid over the entire building platform.

It is then cut around and taped securely to plumbing pipes and laps. 

The formwork for the perimetre is set up at this stage.

Step Four

The RibRaft pods are placed in a grid pattern as per your layout plan. The pods are positioned with relevant spaced. 

The pods can be cut to accommodate the shape and size of the house of the house and allow for load bearing walls.

Step Five

Reinforced bars are placed in the edge beams and ribs - this is done carefully to ensure that the steel is positioned in the lugs provided in the spacers.

As required, all reinforced steel is lapped, and the corner steel laps are tied. If required at this stage the plumbing can be installed and inspected as necessary.

Step Six

Reinforced mesh to mesh chairs are placed on top of the pods - lap and then tie the mesh.

Tie the reinforced bar to the perimeter mesh. Re-entrant corners need additional shrinkage control steel tied to top of mesh.

Step Seven

Concrete is now poured, with thorough care taken to ensure that the pods stay in place (a concrete pump is easiest).

It is desirable to pour some concrete over the pods before placing in the ribs. Concrete thickness above the pods is 85mm. The concrete is then vibrated, then finish the surface and ensure adequate curing takes place.

 More info on our concrete foundation services...
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Page: Ribraft foundations floors Wellington, Waffle slab Christchurch - Last Updated: 24th July, 2014 | Site Map