EPS Floors

Thermal Underfloor Systems

Thermal insulation of buildings is becoming increasingly relevant as energy costs rise and climate change a reality. One area that acts as a thermal heat soak is the under floor area of any building drawing heat generated inside buildings into the ground. The Thermal Under Floor System acts as a easy to install under floor insulation system as well as having a number of other functions and benefits.


The system is a 40mm thick, EPS, under floor, thermal insulating system used as an integral part of ground floor slab systems between conventional foundation walls. The under floor panels are 1,2 x 1,2 m square and are joined together by tongue and groove edging and a propriety expanded polystyrene adhesive.The prime function is to insulate ground floor concrete slabs but it also acts as a moisture proof barrier replacing the continuous plastic sheeting normally used for this purpose. The EPS sheets substitute approximately 50% of the concrete used in conventional concrete floors and due to the lower concrete volume the steel mesh size used can also be reduced.

Product Benefits

  • Ground floor insulation -EPS is used in a multiplicity of applications for its thermal insulating properties. The EPS sheeting acts as a thermal barrier to prevent under floor cold penetrating rooms and keeping heat generated in houses from being dissipated into the ground.
  • Waterproof barrier – EPS is impervious to water and the thermal floor systems’ tongue and groove joining of the EPS sheets provides a continuous under floor moisture barrier. Plastic sheet DPC membranes are thus no longer necessary.
  • Concrete reduction and reduction of potential for surface cracking
  • The 40mm EPS sheets replace almost half of the concrete used in a conventional 85mm ground floor slab reducing cement usage and the heavy labour required in placing the concrete. As the concrete volume is halved the shrinkage stress of the concrete is reduced and, as the EPS spacer blocks ensure the reinforcing mesh sits just below the floor surface, its function to reduce cracking is optimised.
  • Reinforcement mesh size reduction – As the concrete volume is reduced the mesh size can be reduced typically from a 193 mesh to a 100 mesh. This reduces the cost and eases material handling.
  • Optimisation of underfloor heating systems
  • If under floor heating is installed the EPS thermal underfloor system should be obligatory. EPS will ensure that heat generated is not absorbed by the ground and is forced upwards into the house itself.
  • Long life – EPS is rot and rodent proof and dimensionally stable and thus will retain its thermal insulating and moisture barrier effectiveness for the life of the building.
  • Cost – The elimination of the need for plastic sheet DPC, the substitution of concrete with EPS at near cost equivalence and the reduction of the size of the reinforcing mesh means that the EPS composite floor system will give the advantages of thermal insulation at no extra cost.
Suspended Floor and Roof Slab System

Thermal Acoustic Slab System
With ever increasing building costs, the requirement for rapid building and greater awareness of energy conservation as an important aspect of building design, expanded polystyrene (EPS) is becoming increasingly used in modern day construction. The Thermal and acoustic slab system (TASS) uses the properties of EPS – thermal and sound insulation, lightweight, accuracy in moulding and cost competitiveness as the cornerstone of a patented multi storey floor slab system.

TASS is a combination of a moulded EPS block and cold rolled steel channel to form a ‘rib and block’/coffer slab system for multi storey buildings.
The system comprises a priority high strength galvanised steel rib which supports the high density Thermal Acoustic Slab System EPS void formers.

The system is completed by the placement of reinforcing bars between the TASS blocks in both directions, reinforcing mesh above the blocks and concrete to fill the channels, encapsulate the rebar and mesh to form the structure of the floor slab. The beams which are created by the concrete infill and rebar in the gaps between the Thermal Acoustic Slab System blocks creates a monolithic structure.

The Thermal Acoustic Slab System void formers are left in place and act both as a thermal and sound insulator.

1) The floor slab is designed taking into account the span and load bearing requirements combining the variables of rebar size and configuration, concrete beam depth – which can be controlled by the Thermal Acoustic Slab System block depth, and the horizontal floor slab and reinforcing mesh.
2) Support wall structures are built as normal.
3) Steel ribs are placed uni-directionally onto the supporting walls. These are propped at 1,6 metre intervals to support the wet concrete and construction loading.
4) Steel reinforcing is fitted between the TASS blocks in both directions.
5) Steel reinforcing mesh is placed above the blocks on EPS spacers to position the mesh near the surface of the concrete slab.
6) If needed, formwork is placed around the perimeter of the floor area and service ducts to confine the concrete pour.
7) Concrete is poured to complete the slab.

8) Ceilings can be either suspended or plastered with a propriety EPS plaster system.

TASS can be used in the following application areas:
– double storey residential
– multi storey commercial buildings
– hotels
– flats, duplexes and apartment buildings
– shopping centres
– suspended ground floor slabs
– renovations

Reference: ABP Building Products