Beam & Block Floors

Bison Precast beam and block flooring system is quick, easy and economical to install. It offers numerous advantages, including improved acoustic performance and fire resistance. It is particularly suitable for intermediate flooring for houses where sound reduction, fire resistance and thermal mass are amongst its key benefits. The system consists of inverted pre-stressed T-beams with either lightweight aircrete (Thermalite) or dense and medium dense aggregate block infill.

Beam and block is a robust solution for cost-effective suspended floors. It is suitable for use on ground and upper floors in all kinds of construction, from residential to commercial buildings.



Beam and Block components

Inverted ‘T’ beams

Lightweight Thermalite Block

Medium Dense Aggregate Block


Bison Precast prestressed concrete beams exhibit an upward curve known as camber, which is a result of the compressive force near the bottom generated by the prestressing tendons.

An allowance of span/300 should be taken into account in floor finishes or bearing levels.

High Performance
  • Prestressed beams span further, reducing foundation costs
  • Superior levels of fire resistance and sound reduction
  • Superior load-span capability enabling use in a wide variety of applications
  • Unaffected by damp, rot or vermin
Simplicity of construction
  • Quick to install
  • Working platform for early access for follow-on trades
Quality Service
  • Available nationwide either supply only or supply and install
  • Complies with all relevant standards and manufactured in accordance with BS EN 15037
  • Thermal mass helps reduce carbon footprint over the lifetime of the building


Block & Beam Construction Details

All Bison Precast flooring systems are supported by comprehensive layout drawings, specifications and details relevant to each application.

There are three beam types, which are produced in standard profiles of 150 x 125mm, 150 x 215mm and 225 x 135mm (depth x width) to give a range of capacities to suit all loading options.

Beams are placed at appropriate centres depending on span and applied load.

Beams are positioned in accordance with the layout drawings, perpendicular to the end supports with a nominal bearing of 100mm to each end when supported by brick or block. A 75mm nominal bearing is required when supported by steelwork.

The beams may be staggered at the internal walls and multiple beams may be required to support partition walls.

A wide range of infill blocks are available for use with the system including Floorblock from Forterra Thermalite.

Forterra also provides a choice of medium and dense aggregate blocks.

Where required, blocks should be cut using suitable mechanical means to leave a clean, vertical, square-edged face.

Once all the blocks have been placed in position the floor is grouted using a 4:1 sharp sand/cement mixture, which is brushed in the direction of the beams and then at right angles to ensure all joints are completely filled.

Section Details

Typical Layout

Beam and block offers simple and robust detailing as illustrated below.

For construction purposes please refer to site-specific layout drawings provided by Bison Precast.

1  Edge detail paralleled to span

Section showing edge block laid on a split course block and built into the perimeter wall.

2  Staggered bearing

Section showing beams sharing a minimum 100mm bearing on internal wall.

3  Load supported off floor

Section showing multiple beams concreted together to support wall over. Number of beams and centres required are dependent on the weight of the wall.

4  Edge detail perpendicular to span

Beam ends laid onto a DPC and spaced out using the block infill, with a minimum of 100mm bearing. Blocks are bedded onto split course blocks and built into the wall.

5  Change of span direction

Section showing the change in direction of beam span and the maximum cantilever allowing for run-out purposes.

BIM Downloads

Beam and Block Components
Loading of Beam and Block
Beam and Block Partition
Stack of beams
End cover of tendons
Bearing requirements
Trimmer Angles
Floor U Value
DOP HV Beams

Load Span Tables

Beam and block - with 1.8kN/m² for finishes

Where 'X' equals effective beam centre

Case Studies

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Sewstern Self Build


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