As with all screeds the performance and finish achieved can be affected by the conditions on site at the time of installation, and for a short period of time afterwards.  High temperatures can be harmful for Screed Mortar. with particular issues related to early drying (too rapid evaporation of water) which can lead to cracking.

The temperature for supply of screed mortar in hot conditions is stated within

BSEN 8204-7 (pumpable self-smoothing screeds)

“The temperature of both the base slab and the air in the area where a screed is to be installed should remain in the range of 5°C to 30°C, while the screed is being applied, and subsequently for at least 72h”.

 Guidelines for Gyvlon Screed Installation in Hot Weather 

• Do not apply Screed Mortar onto Hot surfaces / Directly affected by Solar Gain.
• Work should stop at air temperatures of greater than 30°C and can resume again at 30°C and falling.
• Ensure the installed screed is protected from Direct Sunlight / Draughts and poured into a watertight location with internal temperatures below 30 °C for at least the next 24hrs.
• Application of the screed in hot weather is optimal later pm to allow cooler conditions during critical phases of setting.

Gyvlon screeds are calcium sulphate based and therefore setting time will not be accelerated significantly in the manner affecting cementitious based materials, however very high temperatures may retard the setting.

Note:        Supply of screed mortar at greater than 30°C, will be at the discretion of the screed producer.