What is a raft floor slab ? It is an on ground system eliminating the need for footing excavation and construction. It incorporates reinforced ground beams and ribs, polystyrene pods, spacers and a concrete topping all in one pour. If required structual piles are incorporated into the system to penetrate poor ground and support structual in good ground below. Shear key piles can also be used to prevent horizontal slipping of at risk structures. 

What are the advantages:

• Spacers that allow ground beams of any width (in multiples of 100mm) to be easily constructed. This means that the system has multiple uses and gives designers options when designing solid masonry, concrete or multi story timber houses.
  
• The solid polystyrene pods offer multiple thickness options. This gives designers even more options when designing floors, as stiffness requirements can be easily adjusted to suit each project by speciying the pod depth. Stiffness can therefore be easily increased for heavy structures on poor ground, or decreased for light structures on good ground.
  
• 1200 x 1200 wide pods reduce total floor costs as steel, concrete, spacer and chair usage are minimised. They can be cut in the factory or on site using a saw or suitable hot wire. They contain a percentage of recycled material, which ensures that they are cost effective. Excellent insulation is built into the system.
  
• Topping slab depths of 85 or 100 mm giving designers even more options.  

Typical floor components: