Design Considerations
CUBE6 beam and block flooring is the ideal solution for suspended ground and upper floors in housing and non-domestic dwellings. Where a heavy point load is to be applied to CUBE6 beam and block flooring i.e. garages, it is recommended that the floor should have concrete of minimum grade C20 reinforced with an A98 mesh to distribute the load.

Floor Finishes
CUBE6 beam and block floor is suitable for the application of a sand/cement screed as a directly bonded screed or on a separating membrane. Where the screed is laid over thermal insulation the screed should be minimum 65mm thick. Where the floor finish is poly/chipboard nominal levelling screed may be required.

Site preparation and resistance to moisture
A suspended concrete floor should incorporate:

  • A damp-proof membrane (to be provided if the ground below the floor has been excavated below the lowest level of the surrounding ground and will not be effectively drained) and
  • In those situations where there is a risk of an accumulation of gas which might lead to explosion, a ventilated air space. This should measure at least 150mm clear from the ground to the underside of the floor (or insulation if provided).
  • Where the ventilation referred to above is provided, two opposing external walls should have ventilation openings placed so that the flow of air will have a free path between opposite sides and all parts. The openings should be large enough to give an actual opening of at least equivalent to 1500mm˛ for each metre run of wall or 500mm˛ per square metre of floor whichever is the greater.

No oversite or other seal is required. The only requirement is the removal of top soil and vegetable matter and the provision of a void to accommodate any likely ground movement.


Good building practice dictates that any suspended ground floor requires ventilation. The NHBC recommends that the rate of ventilation is not less than 600mm˛ per metre of external wall. The combined air brick and ventilator supplied by CUBE6 provides a free vent area of 6600mm˛ and should be fixed at no more than 3 metre centres. Opposing external walls should have ventilation points to provide a free air path.

If another type of air brick (especially one made from clay) is to be used it may be necessary to increase the number of ventilation points.

Design Calculations
The downloadable design tables are given for guidance only. When using maximum or near maximum spans consideration should be given to the effect of camber and deflection on partitions or finishes.

Allowance should be given to specific line, point and distributed loads from partitions and allowances within BS6399. CUBE6 staff will be pleased to offer design advice upon request. All calculations are in accordance with BS8110.