At UK Screeds, we are often asked about the many benefits of our liquid screeds – and there are a lot of them – but we also get questions about whether there are any disadvantages.
So, let’s get that one out of the way before we go any further. Yes, there are a couple of downsides, one of which is that, for rather obvious reasons, you cannot use them on sloping floors in wet rooms!
The other disadvantage is laitance. As the screed dries, it forms a layer of fine particles on the surface. This is called laitance and it needs to be removed before you lay the final flooring because if not there can be problems. However, we do this by sanding the screed surface between 7 and 10 days after it has been poured. It is important not to leave it any longer than this because it will become harder to remove and may prevent the screed from fully drying out properly. When laying tiling, it is important that an adhesive that is compatible with a calcium sulphate screed is used.
So those are the elephants in the room, but after that everything else is benefits when compared with a sand and cement screed.
When we are asked to lay a floor screed in Maidenhead, the process is far faster than you could ever lay sand and cement by hand. We just connect a pump and hose to the delivery truck and pump it into place. We can cover 100 square metres in 45 minutes! This saves a considerable amount on labour costs because if you are laying a sand and cement screed by hand it is difficult to cover 100 square metres in a day!
No Curling And Minimal Shrinkage
Our screeds can also be laid more thinly than sand and cement because they do not curl, and any shrinkage is absolutely minimal. There are big advantages if you are installing underfloor heating in a new building, or for that matter, retrofitting it. If you are doing the latter, quite obviously you will lose some height in the room because you need to cover the heating pipes. However, when using our liquid screed, the overall depth of the screed can be as little as 45mm. this compares very favourably with sand and cement which needs to be at least 75mm overall and can often be 100mm.
Of course, that also affects the overall drying time of the screed before the final flooring can be fitted. A thinner screed will obviously dry a lot faster than one which is much thicker.
That also has benefits for energy saving because the screed will heat up faster and bring the room up to the desired temperature, and uses less energy to do so, which of course translates into lower heating bills. The actual material also has nearly twice the thermal conductivity of sand and cement, again cutting down on the heating time.
Finally, our screeds will always achieve Surface Regularity 2 (SR2) and in most cases SR1, which compares very favourably with sand and cement which will struggle to achieve SR3.