At UK Screeds, we have been providing screeds and underfloor heating for building projects since 2002, so we are coming up to our 20th anniversary next year. Founded in Oxford, we have now expanded to 11 branches throughout England and Wales, and we are planning to open more new branches so that we cover the whole of the UK.
We supply and install liquid screeds, which are such a vast improvement on the traditional sand and cement screeds which are still available, that it is not surprising that they have become so much more in demand over the last few years.
Sand and cement screeds consist of sand and cement – rather obviously – whereas the liquid screeds that we manufacture and install use calcium sulphate as the binder instead of the cement. Dry – anhydrous – calcium sulphate becomes gypsum when it is mixed with water, and this is why our screeds are known by a variety of names such as gypsum screeds, calcium sulphate screeds, anhydrite screeds, and also liquid screeds – because they are in liquid format – and self-levelling screeds because, being liquid, they level themselves out when they are poured. That is all a bit of a mouthful of terminology, but they all refer to the same product.
Liquid screeds have so many advantages over the traditional type, not the least of which is how quick they are to install. When you have a sand and cement screed it has to be mixed either on site or delivered ready mixed, and then it has to be barrowed and shovelled on to the substrate and levelled out by a man with a hand trowel. As you can imagine, that takes a fair amount of time.
Conversely, our liquid screed is delivered to site ready mixed, and we simply connect a pump with a long hose and pump it on to the substrate. Because it is liquid it flows all over the area and settles down pretty much level (hence self-levelling) and the process is very quick indeed. We can often cover an area of up to 2,000 square feet in a single day. Compare that with a man on hands and knees trying to level out sand and cement with a hand trowel. He is lucky to do 100 square metres in a day.
However, There Is More
But there is more to it than that, especially if you are installing underfloor heating at the same time, which we are often required to do. Underfloor heating comes in two forms – electric or water-based. Unfortunately, electric underfloor heating is really only suitable for small areas such as a bathroom because of the expense of electricity tariffs. A bathroom is only used for short periods, too.
It also seems from what we have read in the news very recently that electricity tariffs are going to increase considerably over the next few months.
We install water-based underfloor heating which is powered by something such as your boiler, or perhaps a ground source or air source heat pump, and heats water which is pumped through a pipe system.
When you use a screed of the traditional variety, it is very difficult to ensure that the heat pipes are fully enclosed by the screed, whereas a liquid screed automatically envelops the pipes without leaving any voids or gaps. So, the result is that the heat is spread evenly into the room. Furthermore, anhydrite screeds have almost double the thermal conductivity of sand and cement, so it needs less energy to achieve the same temperature.
However, there is one thing which our liquid screeds need which is not required if you use sand and cement. As the screed dries, it produces a layer of laitance – fine particles – on the surface, and it is essential that this is removed before attempting to attach the final floor surface. We do this by using floor sanding machines in London – and everywhere else – between 7 to 10 days after the screed has been laid.
This is not a vey long process, but it is essential, especially if you are going to lay tiles or anything else that is glued to the screed surface. Once that process has been completed, the screed is left to fully cure, after which the final flooring can be laid without any issues.