What is Screed & Why Do You Need It?
Screed is a type of anhydrate mixture that is poured on top of a floor to make it level. Screed is almost always required as a way of levelling your floor before finishing materials can be installed (it should be noted that screed can be left bare in lieu of a tile, or hardwood floor on top). For this project we Lafarge’s Agilia Afina Screed.
We choose this product because:
- It’s a highly flexible product that does not require construction joints.
- Other renovations could continue within 24-48 hours.
- Agilia has excellent finishing characteristics with a smooth flat surface with no curling.
- Agilia is a free-flowing pumpable product that installs as quickly as it can be pumped from the truck (very fast!).
Floor Surface Preparation For Screed Self Levelling Cement
In order to pour a screed floor, you must first cover the entire surface area with a plastic film. By incorporating this membrane your floor isn’t susceptible to damage from shifting foundations or settling. Since we are working with a liquid product, any holes in the floor and gaps in the plastic membrane must be sealed with tape. Entrances, stairs and thresholds need to be shored-up with plywood. These steps prevent the screed from simply draining into the basement before it has a chance to dry.
How To Know How Much Screed Is Required
How much screed required depends on the condition of the floor. A floor that needs to be raised by inches requires much more product than one that only requires a minor adjustment. Using a laser level we measure the floor and apply white markers that are cut to size and glued to the floor. When the white marker submerges in liquid screed we know that enough product is in that area for the floor to self-consolidate.
Datum laser level placed at the highest point on the floor
The Cement Truck Arrives Screed Application
Once the Lafarge cement truck arrived the installation process doesn’t take long. We use an industrial cement pump which transports the liquid screed from the street to the interior. Ensuring enough product is applied to each section. Working with self-levelling cement is all about the preparation because once it starts flowing your work is almost complete. For this project, 2 workers handled the hose and applied the screed as it pours onto the floor.
Meanwhile, 2 workers operate handheld aluminum bars called dapples. Dappling is done by gently agitating the liquid in a north-south pass and finally an east-west pass which removes any air trapped within the liquid ensuring a smooth surface finish.
Screed flows into the pump
Screed flows onto the floor with the consistency of water