At UK Screeds we are often asked about the benefits of liquid screeds as compared with the traditional one of sand and cement, and the answer is that there are very many. In fact, there are so many that it is difficult to know where to begin.
Let’s start by taking a look at traditional sand and cement screed and see how it is prepared and laid.
The main purpose of a screed is to ensure that the final flooring is as flat and level as it can possibly be. There is no law which says that this must be so, but if you try to lay the finished flooring on a surface which is not flat and level, especially if it is something such as tile or stone, there are going to be issues. Indeed, tile or stone laid on such a surface such as a concrete substrate will be subject to cracking and that is the last thing that you need in a new building – or any building.
Unfortunately, the traditional sand and cement screed has to be mixed in a cement mixer on site, or alternatively can be delivered ready mixed. When mixed on site there are going to be differences in the consistency. Either way, the screed is then laid by a labourer on hands and knees using a trowel in order to get it as flat and level as possible. Not only is this very hard work, but it is also time-consuming.
There is a measurement of the level of a surface which is called Surface Regularity and is divided into SR1, SR2, and SR3. SR1 is High Standard, SR2 is Normal Standard, while SR3 is Utility Standard. To measure, you need a straightedge of two metres which is laid on the floor surface and any gaps under it are measured with a slip gauge.
SR1 can have a maximum gap of no more than 3mm, SR2 is 5mm, and SR3 is 10mm. When using a traditional sand and cement screed, it is highly unlikely that it will achieve anything higher than SR3. Conversely, if you use a liquid screed which is what we install as a liquid floor screed company in Gloucestershire, and which is self-levelling, we will always achieve SR2 and usually SR1.
Then there is the speed of installation and drying. On any building contract, time is of the essence, because overruns can result in penalties which can make huge dents in profits. When we use our liquid screed, we deliver it to the site ready mixed, and we then pump it into position with a pump and a long hose. Because it is liquid, it is virtually self-levelling and all we then need to do is to run over it with a dappling bar in order to remove any air bubbles and then leave it to dry.
Result? We can pour a liquid screed to cover an area of 100 square metres in 45 minutes, and as much as 2,000 square metres in a day. Now compare that with a labourer working on hands and knees using a traditional sand and cement mix. Our teams can cover up to 20 times what an individual labourer using sand and cement can do.
We haven’t finished yet.
If you are installing underfloor heating, which is being installed in new builds more and more today, you need to cover the heating pipes completely. This is virtually impossible to achieve with a traditional mix. There will always be gaps and voids.
When you use a liquid screed, it will always completely envelop the heating pipes. In fact, it cannot do anything else, because it is liquid. What that means is that the heat will be transferred evenly into the room, whereas if you have gaps there will be some areas which are warmer/cooler than others. Not only that, but our liquid screed has thermal conductivity that is nearly twice that of sand and cement. That means that you will use less energy to heat the room which translates into saving more money on heating bills for the life of the building.
There are several more benefits such as the fact that the screed will be dry enough to walk on within 24 – 48 hours, it will not suffer from shrinkage or curling at the edges, and more.