Royal Mail Sorting Office

Royal Mail Sorting Office

Client: Wates Retail
Role: Specialist Sub-contractor


  • Sika Polymer Screed laid at 100mm


  • 1100m2 floor slab
  • Existing cracks to slab cut out and reinstated with Sika 52 resin
  • Floor primed with two coats of Sikafloor 161
  • Application of 2mm of Sikafloor 264 as self-leveling system

Wates Retail who were appointed by the Royal Mail to fit out a new sorting office called in the specialist flooring division of Cemplas Waterproofing and Concrete Repairs Ltd as issues had been identified within the floor slab which had been poured 10 months earlier.

Royal Mail Sorting Office

Following an inspection by specialist contractor Cemplas, and specialist manufacturer Sika Ltd, Cemplas were appointed the task of undertaking the remedial works to over 1100m2 of the floor slab. A survey by Cemplas did not reveal any cracking in the slab movement joint confirming the slab had not shrunk during the 10 months it and that no special requirements were needed.

Work began by sand blasting the floor slab and the lignite was removed by drilling and removing the contents with a Vac. Following on from the removal of the lignite, holes were filled using a mix of Sikafloor 264 and quartz sand to produce a scratch coat. This was also used across the surface of the concrete to fill any smaller holes after the shot blasting had taken place. Any existing cracks to the slab were cut out and reinstated with Sika 52 resin.

A scratch coat was applied by trowel to level up the substrate blended from 1-part Sikafloor 264 to 1–2 parts dry clean silica/quartz sand by weight to leave a level surface, pinhole free to allow an ideal surface for over coating.

Once prepared the floor was fully primed with two coats of Sikafloor 161 by using short haired rollers and left to cure for a minimum 12 hours.

When the primer had fully cured Cemplas applied 2mm of Sikafloor 264 as a self-leveling system. This was filled as required using Sika 0.06-0.3mm Quartz Sand. Within 10 minutes of applying the self-leveling system Cemplas operatives thoroughly spike rolled the coating at right angles to release any trapped air and remove any remaining trowel marks to provide a smooth, level, pinhole free surface achieving a consistent material thickness.

Other specialist flooring operations undertaken by Cemplas include:

  • Traditional screeds (Sand Cement);
  • Fast drying and specialist accelerated screeds;
  • Polymer modified screeds (SBR);
  • Floor levelling compounds;
  • Granolithic screeds;
  • Bonded, unbonded and floating screeds;
  • Free-flowing self-levelling screeds;
  • Anhydrite free-flowing self-levelling and self-compacting screeds;
  • Screed strengthening for weak and porous screeds;
  • Chemically resistant Screeds.
Royal Mail Sorting Office