A good quality cement-based self-levelling compound is designed to have high flow
characteristics and good self-healing properties. This allows the product to find its own
level after being applied, while also drying to create a smooth flat and hard surface.
Water addition plays a critical part of how these products flow and behave. Consequently,
in colder months they may take longer to dry due to the nature of the high-water content.
Moisture sensitive flooring such as vinyl or timber can normally be applied after 24hrs, or
sooner depending on the product applied. In warmer temperatures, most self-levelling
compounds will dry faster than what is stated on the relevant TDS. This is due to the
higher ambient temperatures assisting with the hydration process (water loss).
In colder temperatures (12°C & below) this drying time may take as long as 48+ hours
due to the nature of self-levelling compounds having such a high-water content.
One of the most important things to remember at these low temperatures is the time of
the day. These types of products should not be installed after 2pm on a construction site
where there is no internal heating and when ambient temperatures will drop below 8°C
over night. If the ambient temperature is 8°C the concrete substrate temperature would
be 5-6°C and at these low temperatures cement-based materials are put to sleep and
thus severely affecting the curing process. In most cases the strengths will be greatly
reduced but, in some instances, where the applied product has been put to sleep it may
need to be completely removed and re-done.
To offset the cold temperature effect – Best Practices
1. Increase airflow in the rooms where the self-levelling compound is being applied.
Cross ventilation (open windows on opposite sides of the room)
Put fans in the stairwells to help remove the moisture from the room and assist the drying speed.
2. Warm the water you are using to mix with the chosen self-levelling compound by
adding 20L of hot water with 80L of cold water (from the tap) into the onsite
reservoir. This will increase the overall water temperatures without affecting the
workability of the mixed product.
3. Use electric heating devices to bring the room temperature up (18-22°C is ideal).
Do not use gas heating devices as they will leave a film across all horizontal
surfaces causing bonding issues with subsequent applications.