Liquid Screed Installation Information

 

  • Before screeding can commence the area to be screeded must be made watertight to prevent leakage.
  • The polyethene slip membrane installed over the insulation must be overlapped and sealed to prevent loss of screed. If Under floor heating is used It is essential that the pipes are laid on top of this.

 

  

 

  • Pipes or cables must be securely fixed to prevent floatation and lifting during application of the screed.
  • Best practice is to fill pipes prior to application of the screed to check for leaks, this also reduces the risk of pipes floating whilst the screed is being poured.
  • Minimum cover to pipes or cables must be 25mm below finished screed.
  • If underfloor heating trays are used they must be fully secured down to prevent them from raising.

 

liquid screed underfloor heating pipes screed underfloor heating pipe clips guildford 

 

Priming the substrate for Liquid Flow Screeds

 

You will need to prime the existing substrate before screeding can commence, this is to kill the suction to prevent the material drying too quickly.

Any SBR primer can be used, but if there is grease present it would be wise to use a liquid DPM like blackjack.

 

  

 

As with all screeds the performance and finish achieved can be affected by the conditions on site in which it is installed and for a short period afterwards. The following watchpoints should be adhered to during this time.

  • Protect from frost. Apply the same winter working restrictions as when placing concrete, i.e. work should stop at temperatures of 5°C and falling and may resume again at 3°C and rising.
  • Providing internal temperatures are maintained work may continue when the outside temperatures are as low as 2°C.
  • Liquid Screed cannot be laid in temperatures of 30°C and over – high temperatures extend setting times and may reduce the final strength of the screed.
  • A humidity of 50% and above in the air should be maintained during the first 48 hours after application.
  • The screed can be walked on 24 to 48 hours after application dependant on site conditions with normal site traffic and erection of non-load bearing partitions after 7 days.
  • A liquid screed is not a wearing surface, and protection from other construction trades may be necessary for areas of heavy use such as loading bays.
  • Removal of the laitance will help to dry the floor.
  • Under like for like conditions liquid screed dries at the same rate as a traditional sand and cement screed.

Approximately 1mm/day up to 40 mm thickness. This increases or screeds thicker than 40 mm and in poor drying conditions.