Until recently, underfloor heating has been perceived as a luxury specification and therefore only suitable for high-end homes, and as a result it has been the case that in lower cost housing, specifiers have opted for a traditional radiator system for heating. However, that is beginning to change as it has been realised that combining an underfloor heating system with a liquid screed can be economic for any type of property, including at the affordable housing end of the ladder.
In fact, recent studies have shown that the costs of the installation of a radiator system compared with that of an underfloor heating system using liquid screed are very similar. Certainly, the screed has to dry fully before the final flooring can be laid, but this can be speeded up using the underfloor heating itself or the underfloor heating combined with force drying, and this can make a considerable reduction in the time required before the flooring can be laid. In fact, if you allow for the cost benefit of the time saving on the project it can make installing underfloor heating the best option.
Apart from other considerations, underfloor heating is the way forward when it comes to the environment, as it uses less energy than a radiator system and produces a better result. When you have underfloor heating, the whole room is heated evenly from the floor up including the furniture and the people within it.
On the other hand, a radiator system heats the air around it and that heat rises upwards to the ceiling where, if you think about it, not a lot of heat is needed. The hot air then circulates around the room and will leave certain areas – largely in the middle of the room – less warm. This will depend on the position of the radiators, of course. The circulation of the air also carries with it dust, which can be harmful for people with allergies or breathing difficulties.
With underfloor heating there is the choice of electric heating or water-based heating, and of the two, water-based heating is more economical. This uses water which is heated by a boiler or a heat-pump – either ground-source or air-source – and is pumped through a heating pipe evenly around the underfloor of the room. Thus, the heat is spread evenly, and the temperature will only drop by about 2°C at a height of two metres.
Then there is the question of floor screeding in Newbury, or wherever the project is. At UK Screeds, we install water-based underfloor heating systems and combine them with a liquid floor screed, which has many advantages over and above the traditional sand and cement. Just to begin with, the thermal conductivity of our liquid gypsum floor screeds is nearly twice that of sand and cement which means that less energy is required to achieve the same temperature in the room.
The next point is that our liquid screeds can be laid considerably thinner than sand and cement, which also contributes to energy saving. There is simply less screed to heat before the heat reaches the room. A sand and cement screed is typically laid at a depth of 75mm or more, whereas our liquid gypsum screed can be laid to a depth of 25mm above the heating pipes making a total of 40mm. The screed is also composed of about 35% recycled material which again is eco-friendly.
Our liquid screed is also far faster to lay than a sand and cement screed. The latter is levelled out by a man on hands and knees using a trowel, which is a lengthy process. Our liquid screed is delivered to site pre-mixed and we pump it into position using a pump and a long hose. We then dapple it in two directions with a dappling bar, after which it is left to dry for 24 – 48 hours, at which point it will be dry enough to walk on.
With this method, we can lay up to 2,000 square metres of screed in a single day which is around 20 times faster than laying sand and cement by hand. The screed does need sanding after 7 – 10 days to remove laitance and we do this using a floor sanding machine. The screed can then be dried using the underfloor heating alone or in combination with force drying, reducing the overall drying time before the floor can be fitted to as little as four weeks.