Removing Laitance from Screed
Liquid screed has rapidly become the default flooring finish over the past few years. It’s an innovative technology that offers multiple benefits when compared with the use of dry, or traditional screed. Contractors that have switched from dry screed to liquid screed tell us that it’s easier to lay, more cost-effective, can be pumped on site using a small team of specialists, and dries rapidly. The resulting floor is also extremely tough and durable.
Calcium Sulphate, or Anhydrite Screed
Key to the success of liquid screed is the fact that the cement-based binder has been replaced with calcium sulphate. When mixed with water this dry ingredient will form tough, crystalline Gypsum for between 3-7 days. Once the chemical reaction is complete, and the calcium sulphate is used up, any remaining water in the screed mix rise to the surface of the screed to evaporate.
What is Laitance?
Laitance is the crumbly coating of fine particles that forms on the surface of a screed floor during the curing period. Its presence indicates that excess moisture is finding its way to the surface, which could inhibit the rapid drying times normally associated with liquid screed. It’s also important to note that where laitance has formed, the floor will need to be sanded before tiling, as the layer is too weak to hold the finish.
Removing Laitance from Screed
The appropriate treatment for laitance removal floor sanding. This should be carried out 7-10 days after the initial application. The use of a sanding machine is also known as ‘abrading’. This means that the surface is scoured to ensure the removal of all dust and fine particles clinging to the screed finish.
Once the sanding is complete, all excess dust is removed using an industrial vacuum cleaner. The resulting surface is now durable, and stable enough for the installation of the flooring finish. We would always recommend to clients that a primer is applied to the screed surface before tile adhesive is applied.
RB Liquid Screed Expertise
We pride ourselves on both the quality of our materials, and the expertise of our screed specialist installers. Contractors and developers welcome the opportunity to talk through their screed installation with experts, prior to the pour. And they’re on hand throughout the process to offer support, advice and guidance at any stage.
Liquid screed rarely presents problems during installation – which is why it’s so popular. If, however, there’s an issue with laitance, or shrinkage, our flooring specialists will be able to offer a rapid and effective response. We don’t believe in ‘sticking plaster’ solutions at RB Liquid Screed. Any concerns that clients have are dealt with responsibly by knowledgeable installers.
Customer-Centred Liquid Screed Services
The majority of our clients are developers or contractors, and time is their most precious commodity. We understand the pressured environment, and have a number of rapid response teams ready to start work at any given time. Every installation is professionally project managed and the client satisfaction is paramount. We always ask for feedback, and if you have any criticism, we take the time to listen and learn from it.