Floor Preparation

Water Tight       

  • The building must be made be weather tight - the roof and external doors /window openings must be fitted with either final fixtures or clear polythene.

Exposed Edges

  • Install temporary formwork to exposed edges (eg door openings or level changes)  


  • Remove all dust, debris and contamination from the floor surface.


  • Ensure that all high/low points are removed from the sub-base and that insulation boards are laid flat.
  • Insulation boards should be tightly butt jointed with staggered joints.


  • Install a polythene separating membrane to floor (500 guage or similar) join with 50mm tape. Ensuring that all air pockets are removed and are free from punctures and creases.
  • Lap joints should be 100mm and where necessary continue the polythene up the face of all wall/floor joints to the full depth of the screed.
  • Perimeter isolation strip should be fixed at wall/floor junctions and around any columns, pipework etc

Underfloor Heating    

  • When used on underfloor heating we recommend using polythene to separate the membrane.
  • All heating pipes and cables must be securely fixed down.
  • Warm water systems should be filled prior to the application of to reduce the risk of pipes floating when the screed is poured.

Minimum Application Thickness:

  •  Bonded, 25mm
  •  Unbonded, 30mm
  •  Floating commercial, 40mm
  •  Floating domestic , 35mm
  •  Underfloor heating (min cover to pipe),  30mm

Please make an allowance for tolerances and any isolated high spots as this will impact on the overall depth and material usage.