Cemfloor Installation Process

A Step-by-Step Guide

At McGraths, our Cemfloor Installation Process is of utmost important to us, and we deliver the highest of standards to ensure our screed is installed to perfection. Take a look at our step-by-step guide to the installation process.

Pre-Installation Guidelines & Preparation of Substrate
liquid screed for underfloor heating

1. Site preparation for Cemfloor as bonded screed

  • When Cemfloor is being used as a bonded screed remove all dust and debris from subfloor and vacuum up fine dust.
  • Any cracks in the subfloor must be repaired to stop them showing through and cracking the bonded screed.
  • The day prior to installation apply one coat of a good quality bonding to the subfloor agent and allow to dry overnight.
  • One hour prior to pouring Cemfloor give the subfloor a second coat of bounding agent. This ensures the bonding agent is still tacky, to aid good adhesion/bonding.
  • Minimum depth for bonded Cemfloor is 25mm.

2. Site preparation for Cemfloor floating on insulation

  • When Cemfloor is being used floating on insulation remove all debris from the subfloor and make sure that the floor insulation sheets are fitted tightly and are not loose underfoot.
  • Cover insulation with a good quality polythene sheeting stretched out with no creases and turn up the perimeter walls 75mm.
  • Use 7mm minimum edge expansion strip around all perimeter walls and up stands in the floor.
  • Minimum depth for Cemfloor floating on insulation is 35mm for domestic and 40mm for commercial use.

3. Site preparation for Cemfloor with underfloor heating

  • When Cemfloor is being used with underfloor heating remove all debris from the subfloor and make sure the floor insulation sheets are fitted properly with no gaps between sheets to avoid thermal bridging to the subfloor.
  • Fill any gaps with gun grade expanding foam and cover with polythene sheeting, making sure to stretch out well and return up the perimeter wall 75mm.
  • Depending on heating design specification you could use 7mm minimum edge expansion strip or 25mm insulation strips.
  • After the heating contractor has installed the heating pipes, vacuum to remove any debris caused during pipe installation.
  • A minimum 25mm cover over heating pipes must be adhered to.
  • The heating system can be commissioned 7 days after installing Cemfloor.
Installation of Cemfloor Screeds
Underfloor heating screed
  • The building/structure where Cemfloor is to be poured must be weather tight, with windows and doors fitted. If windows are not fitted temporary provisions should be made by the use of polythene or plywood to block openings.
  • When the mixer truck arrives onsite the driver should ensure the mixing drum at full speed for one minute, this will increase the flow of Cemfloor. A slump test must be take which should read between 230mm minimum and 260mm maximum.
  • The screed should then be pumped into the building to the pre-arranged floor heights given by the site engineer.
  • Cemfloor is then dappled twice in both directions 90 degrees to each other, after the last dapple the screed must be sprayed with a light mist of Cemfloor evaporation control evenly over the entire surface of the screed holding the nozzle of the sprayer about 500mm from the surface.
  • When the screed installation is finished make sure all openings are covered completely to help Cemfloor cure properly failing to do so could cause the surface not to reach full strength leading to issues with floor finishes e.g. tiles are to be fixed to surface.
Finishing Process
Cemfloor liquid screed finishing process
  • After 24 hours the building should be vented by opening all windows and doors if possible this should be done every day until the heating has been commissioned, by opening the windows and door everyday will speed up the drying time of Cemfloor.
  • There is no laitance on Cemfloor screeds so no need for sanding before tiling just the removal of any building contamination on surface e.g. paint spillage and plaster splatters.
  • Before any floor covering are fixed to Cemfloor containing underfloor heating the heating system must be fully commissioned by the heating contractor after this a moisture test must be taken for the fixing of timber floor and vinyls.

 Interested in learning more about Cemfloor?