If you want to hire a liquid screed contractor in Milton Keynes, or for that matter anywhere else in England and Wales, at UK Screeds we’ve got you covered. We have no fewer than 11 branches in England and Wales, and we can help you with screed installation, and also the installation of underfloor heating, from Land’s End not quite to John O’Groats but to the Scottish borders. In fact, we have plans for further expansion so that we can indeed cover the whole of the UK.
Liquid screeds have gained massively in popularity over the last few years because of the many advantages that they have over and above the traditional screeds made of sand and cement. Our screeds use calcium sulphate as a binder, and when this is mixed with water it becomes gypsum, which is why the screeds are also known as gypsum screeds. Rather obviously, because they are liquid they are also known as liquid screeds, and self-levelling screeds, calcium sulphate screeds, anhydrite screeds (that is because before it is mixed the calcium sulphate is anhydrous, which means dry), and no doubt other names as well. They all refer to the same product.
Time Is Of the Essence
Of the many benefits of our liquid screeds, a major one is the speed of laying. On any building project, time is of the essence. You don’t want a situation where you have overruns and can get into costs because of penalty clauses, and for this reason alone, liquid screeds are the perfect answer.
Sand and cement screeds are either mixed on site in a cement mixer or delivered ready mixed to larger sites. Hand mixing means that each batch will vary from the last one, whereas ready mixed ensures that every batch is the same. Whichever way it is, the screed has to be barrowed into place and then levelled out by a worker on hands and knees with a hand trowel. This takes a considerable amount of time.
Our liquid screeds are also delivered ready mixed, but then all we do is to connect a pump and a hose and pump them into place. It is reckoned that this is up to 20 times as fast as laying a screed by hand.
Our screeds also dry very quickly. Once laid they must be left alone for up to 48 hours, but after that they can be walked on. That means that any other trades who need to work on the site are not going to be unduly held up waiting for the screed to dry.
You Cannot Lay The Final Flooring Yet
Although the screed can be walked on after a very short time, that doesn’t mean that you can lay the final flooring yet. Typical values required for moisture sensitive floor finishes are less than 0.5% water by weight or less than 75% relative humidity for impermeable floors, and less than 1% w/w for more permeable floors.
The drying times of liquid screeds are calculated as being 1mm per day for the first 40mm depth of screed, and 1/2mm per day thereafter. This is based on a temperature of 20°C during the whole period, and relative humidity no greater than 65%.
This would mean that a screed of 45mm depth would take 50 days to dry to the point where the flooring can be fitted. Of course, in the UK climate this is not likely to occur, so the actual drying time would be longer. However, if it is required to speed up the drying process, this can be done with the use of force drying equipment. In fact, you could get the full curing time down to around a month this way.
One thing that happens with liquid screeds is that they do produce what is called laitance as they initially dry. This takes the form of fine particles which form on the surface of the screed, and these need to be removed before adding the final flooring. We do this by using diamond grit sanding machines between 7 and 10 days after we have poured the screed. Any longer than this, and it will make the laitance harder to remove. It would also affect the overall drying time of the screed.