Laying Screed in cold and wet weather

January 2015

No one intentionally chooses to carry out a screeding project on a rainy or very cold day. But if you are planning to replace your screed and install a new floor any time soon, you should get ready for the inevitable: laying screed in bad weather.

  • Transportation and storage – To protect sand, cement, and aggregates from rain and moisture, they must be covered with polyethylene sheets. Once brought on the site, all materials should be kept in dry areas, and the cement bags should be stored on pallets.
  • Temperature limits – If young screed is allowed to cure and dry below the freezing point, it will probably be unfit for use. To avoid this, two different temperatures must be considered: 1) ambient air temperature, which should not go below 3°C; 2) floor temperature, which should be maintained at 5°C. If screed is laid below 0°C, the water will freeze and expand by about 9 percent. This could cause a disruptive reaction and make the screed break.
  • Curing and drying times – Most screeds settle and develop strength within five days if kept dry, at or above 5°C. The best way to protect the screed in wet or cold weather is to use polyethylene sheets. These sheets prevent the heat generated by the chemical reactions (e.g. hydration and hydrolysis) in screeds from dissipating, keeping the screed warm enough to cure and dry properly. Additionally, polyethylene sheets can help avoid rain water splashing onto freshly applied screed, significantly lowering the risk of failure.

Polythene curing should only remain in place for 7 days and then removed to allow the screed to dry. In general, water evaporates from the surface and it’s good practice to exchange the air 3 times a day by opening the windows giving good airflow.

Since bad weather extends curing and drying times, and may prevent screeds from drying properly within the set time frames, testing is very important, as it provides contractors and owners with valuable information regarding the characteristics of the screed.

At HomeScreed, our team can help you obtain good results even when pouring screeds in cold weather. Contact us today to discuss your screeding project, and we will plan everything down to the smallest detail.

To find out more about how to get the best screed for your home, download our free guide “Essential guide to the perfectly screeded floor”  

HomeScreed is a division on CSC Screeding Ltd