It is no exaggeration to say that liquid floor screeds are rapidly becoming the norm in the UK for a number of reasons. They have many benefits over the traditional hand laid screeds, not the least of which is the amount of floor are that can be covered in a short space of time.
Traditional floor screeds are either mixed on site or delivered ready mixed, but which ever method is used you then have to get down on your hands and knees and lay the screed by hand. However, a liquid screed is delivered ready mixed and is simply poured on to the substrate, and this means that it is possible to screed as much as 2,000 square metres in a single day, although 500 - 1,000 square meters would be the norm.
Because a liquid floor screed in London is just that – liquid – it is self-levelling and simply needs smoothing out with a dappler after which it can be left to set. A liquid floor screed will dry to the point where it can be walked on in as little as 24 – 48 hours.
Of course, that doesn't mean that you can tile it or add any other floor surface after that length of time. It still has to dry out fully before you can do that, and how long that takes will depend on the depth of the screed. The usual figures that manufacturers quote are that a screed will dry at a rate of 1mm a day up to 40mm, and half that rate after that. So if a screed is 50 mm deep it will take 60 days to dry.
However, those figures assume a constant temperature of 20°C and an average humidity of 60%, both of which are almost impossible to achieve in the UK. Indeed, in average conditions, getting the liquid screed fully dried may take more like 90 days, and this can be a big problem on many contracts where time is of the essence. It can also cost a lot of money, because over-runs may attract penalties which can run into the hundreds of thousands.
This is not actually too much of a problem as the screed can be force dried after seven days. Force drying requires the right equipment and timing but can usually be achieved within a further 21 days. However, force drying is something that is often only carried out as an afterthought when it is suddenly realised that the screed won't be ready for such a long time and it is concluded that some action has to be taken. Force drying should really be a part of the specification for a contract.
Liquid floor screeding is ideal for use when underfloor heating is being installed. It only needs to be 25mm over the top of the pipes, and of course it fills in all the gaps around and under them. A damp-proof membrane is laid on the concrete substrate and then the heating pipes are fastened to tacker boards and the screed can then be poured. The tacker insulation boards prevent heat from escaping to the base. Liquid floor screed has a very high thermal conductivity and is ideal for use with underfloor heating.
You may also lay a floor compound in Essex. This can be used for smoothing out unlevel wood or concrete floors if you are going to lay tiles over the top. If a floor is uneven and tiles are laid on it there is a good chance that the tiles will crack and not last for very long.
However, there are some disadvantages to using a self-levelling floor compound, one of which is that it will not adhere well if the substrate is dusty and has grime. It really has to be spotless before using a floor compound. Another problem is that a floor compound does not provide stability to the subfloor. If the wood loosens, the self-levelling compound may break up causing damage to the tiles.
Yet another problem is laying a floor compound. It dries very fast, and you may only have about 20 minutes to mix, pour, and even it out. This means that you have to have all the tools you need to hand and to work very fast.