Fast-Track Screed Drying – Expert Tips & Techniques
The screed drying process is a real bottleneck, that creates delays for other trades and can impact deadlines. How to reduce screed drying times though? If you get it wrong, you could face consequences like cracking, curling, and reduced compressive strength which will compromise the strength of the floor.
If you’re looking for faster drying times, you need to do it right. Because getting it wrong can lead to costly repairs and rework.
Capital Screeding is a liquid screed supplier and installer for London, Essex, and the South East. In this blog we share some expert tips on how reduce screed drying times. We’ll cover the environmental factors and screed composition as well as ventilation and heating, so that, by the end you’ll have a number of options you can choose from.
Choose Your Screed Wisely to Speed Up the Drying Process
One of the biggest factors influencing screed drying time is the type of screed you choose in the first place.
There are a few of the types of screed you can choose from, each with its own drying characteristics:
- Traditional Sand and Cement Screed – This is the classic mix of cement, sand, and water. It’s a reliable option, but it’s also the slowest to dry – 1mm per day up to a 40mm thickness. If time is of the essence, this isn’t the right choice.
- Flowing Screed (Anhydrite/Calcium Sulphate) – Liquid screeds, are designed for speed. After 24-48 hours the screed should be dry enough for light foot traffic. After 7 days it should be strong enough for heavy loads, and it will reach full strength at around 28 days.
- Fast-Drying Screed – These rapid drying screeds are engineered for rapid hardening, allowing for foot traffic in around 12 hours and heavy work traffic within 24 hours. Even better, they can reach a humidity level suitable for most floor coverings in just 7 days.
Creating the Perfect Drying Environment
Choosing the right screed is a great start, but creating the right environment is just as important for successful drying period. Here’s what to bear in mind:
Subfloor Preparation – Ensure the subfloor is clean, dry, and free from any contaminants that could slow down moisture evaporation. If the subfloor is concrete, make sure it’s fully cured before applying the screed.
Good Ventilation is Important – If air is flowing through the space, it’s able to remove the moisture that’s released from screed as it’s drying. Open windows and doors if you can, especially during the initial drying period. For larger installations use dehumidifiers or fans.
Temperature Matters – Screed dries best in a temperature between 15°C and 20°C (59°F and 68°F). It doesn’t like temperature fluctuations. If the weather is cold, consider use temporary heating solutions, but make sure they offer consistent, indirect heat.
Protect from the Elements – Direct sunlight on screed can cause rapid surface drying, leading to cracking, and rain can add moisture and prolong the drying process. Drafts can also cause uneven drying.
Removing Laitance for Faster Drying and Stronger Bonds
After your liquid screed has hardened (usually within 48 hours), you may notice a fine, powdery layer on the surface. This is called laitance, and it’s formed by fine particles that rise to the surface as the screed dries. It’s a natural part of the process, but leaving laitance in place can slow down drying and weaken the bond between your screed and the final floor finish.
This is because laitance is a barrier that traps moisture. Removing opens the pores of the surface, and the screed dries faster. Cleaning the surface also allows for a stronger bond with flooring adhesives.
Here’s what you need to know about laitance removal:
- Timing is Important: -We recommend removing laitance between 5 and 14 days after the screed is laid. The longer you wait, the harder and more difficult it is to get rid of.
- The Simple Solution – Sanding the surface with a 60-grit sanding machine will remove laitance. You’ll be left with a slightly textured surface, which is ideal for bonding with adhesives.
Force Drying with Underfloor Heating
If you’re installing underfloor heating, you can use force drying. This uses the underfloor heating system itself to speed up the drying process, but it has to be done slowly and steadily to avoid damaging the screed.
Here’s a general guideline for force drying with underfloor heating (you should always consult the screed manufacturer’s instructions for specific guidance):
- Start Gradually – Begin the process no sooner than 7 days after the screed has been laid (this can vary depending on the screed type and ambient conditions, so always check manufacturer’s guidelines). Start with a low flow temperature, typically around 20-25°C (68-77°F), and then gradually increase it by a few degrees each day.
- Maintain Consistent Temperatures – Avoid temperature fluctuations. Aim for a steady increase and keep the temperature consistent for several days before starting to gradually reduce it.
- Ventilation is Still Important – Even if you’re force drying, ventilation is absolutely necessary. Continue to provide good airflow by opening windows and doors or using a ventilation systems.
- Monitor Moisture Levels – Monitor the moisture content of the screed regularly. This will help you decide when the screed is dry for your floor covering.
Why Work With Capital Screeding?
From choosing the right screed and preparing the ideal drying environment to advising on laitance removal and force drying techniques (if applicable), Capital Screeding can give you the expertise and support you need to keep your screed installation on track.
Our experienced screeders proactively address potential challenges in order to reduce delays and keep your installation on track. Our screeding service guarantees an efficient process which won’t disrupt your schedule or keep trades waiting around.
Achieve faster drying times and a flawless floor with Capital Screeding. Get in touch for a free quote – 020 3360 3396
