When you are constructing any sort of building project one of the most important things is to ensure that the floors are as flat and level as possible. Concrete substrates are not flat, and never going to be, and so it is necessary to use a screed in most instances in order to provide a layer on top of the concrete that will be as flat as you can get it.
For many years, traditional screeds have been made purely from sand and cement. This is usually mixed on site in a cement mixer and then barrowed on to the substrate. Here it is levelled out to be as flat as it can be by a worker on hands and knees using a trowel.
There are several problems with this, not the least of which is that even the best worker will never achieve the highest level of flatness which is known as SR1. In fact, it will not be better than SR3.
Of course, working like this takes a lot of time. One worker can only manage 100 square metres in a day at most. Not only that, but as it dries, the screed can shrink and curl at the edges. It also takes ages to fully dry.
However, today we have liquid gypsum in the UK. This is a screed which is made using anhydrous (dry) calcium sulphate which, when mixed with water, converts into gypsum, and is also known as an anhydrite screed.
Delivered Ready-Mixed
These screeds are what we supply and install at Top Mix. The screed is delivered to site ready-mixed in a mixer truck and we then connect a pump and a long hose to it. The screed is then simply pumped on to the substrate. It’s quick and it’s easy. In fact, we can cover as much as 2,000 square metres in a day – 20 times as fast as a sand and cement screed!
As the name implies, liquid gypsum screed in the UK levels itself out because it is a liquid! All our team then need to do is to run over it with a dappling bar in order to remove any air bubbles and leave it to dry.
Drying time? It will be dry enough to walk on in 24 – 48 hours. It doesn’t curl. It doesn’t shrink. It completely covers the pipes on water-based underfloor heating so there are no air gaps.
True, it does need sanding before laying the final floor surface, and it does cost a little more than sand and cement. However, when you take into account the drying time and the speed of laying, this more than offsets any difference in material cost. Liquid gypsum screeds are the way forward today.