Flooring (3)

You have heard the term under floor heating but do not fully understand the concept, it is likely that you have wondered why you should invest in an under floor heating system for your home. If you are like many homeowners, you might have assumed that under floor heating was just for those with more money than they know what to do with who were looking to avoid the feeling of cold hardwood or tile floors when they get out of bed on a winter morning. Many homeowners make the mistake of believing that under floor heating systems are a waste of money and serve no purpose other than a slight convenience. Under floor heating systems are not simply a matter of convenience; they can be used as a reliable heating source for the home. There are numerous benefits to under floor heating systems.

One advantage to the use of under floor heating systems is the reduced need for radiators. Radiators not only take up valuable floor space that is eliminated by the use of an under floor heating system but they also reduce the amount of dust circulating in the room and create a more controlled heating environment. Radiators circulate the air in the room and as a result they also circulate dust and debris in the air as well. Additionally radiators do not provide a uniform heating pattern. They often create cold spots in the room that could be avoided by switching to an under floor heating system that releases heat more uniformly.

Another advantage to an under floor heating system is an overall reduction in heating costs. Under floor heating systems are able to function by using low water temperatures resulting in a reduction in energy consumption because the water does not require heating prior to use in the under floor heating system.

Another advantage that under floor heating systems has over traditional radiator systems is the absence of a vertical temperature gradient. Radiators produce an environment where the floor temperature is colder at the foot level than it is at the head level. This vertical temperature gradient is a result of the way in which the heat is expelled through the radiators. The heat dissipates above floor level and tends to rise creating the undesirable condition where the coldest temperatures are not on the floor level. Conversely, an under floor heating system dissipates the heat energy through the floor creating the ideal condition where the floor temperature is slightly higher than the temperature at the head level.

We take a look at four systems

Underfloor heating

Underfloor heating is the oldest of the four system(1950's). These cables are manufactured by using a high temperature PVC and they have a diameter varying between 4mm to 6mm. This material is very tough and it can take quite a bit of a bad treatment on the building sites. These cables are usually laid onto the concrete slab, are spaced about 75mm across and held by plastic spacers. Once layed, a wet screed of at least 25mm thick or more, is thrown on top of them and it is then either hand or machine floated. The tiling process can take place some few days later. Some other builders throw a dry mixture of sand and cement of about the same thickness and after levelling, start the tiling process immediately.
This underfloor heating system works quite well but has lost popularity because of the long time it takes to go through the thickness of screed and the lack of flexibility in mild climates such as we have in South Africa. The system is also used for the now fashionable coloured screed floors(using oxydes) and wooden floors.

Undertile heating

This system was introduced by us in the early ninety's, when the demand for ceramic tiles versus wall to wall carpet started to climb. Home owners who were willing to replace their carpet with ceramic tiles were confronted with the floor level headache if they wanted to install underfloor heating cables. Because of the growing demand on the market for a suitable underfloor heating system which would not alter the floor-level, we designed an undertile heating system made out of e.t.f.e.(Teflon) which by the nature of the material could allow us to manufacture very thin wires (1mm to 1.7mm). Thanks to the high-tech of this polymer (e.t.f.e), this very important particularity would change the face of the underfloor heating world for ever. A display of this system was on show at the permanent home exhibition in 1993 *(ex-bou, Commissioner Street in Fairview/Johannesburg)*.
After wall-to-wall carpet removal from the existing rooms, it was extremely easy to lay the heating wires on the flat cement floor. Once layed, a meshing of polyester material (nowadays a hessian fabric or a fiberglas meshing) was fitted over the wires and a special mixture of cement, latex (plaster key) and water was poured and levelled with a steel trowel. A couple of hours later, the wires were beautifuly sealed onto the floor ready to be tiled with a minimum of thickness(+/-4mm) which means that there will be no change in floor-level. A revolution! not a French One, though. This operation is needed to protect the wires from rough treatment and make the tiler's job easier. Quite a lot of pictures are available for further viewing.

Undercarpet heating

Undercarpet heating was the first system we started with. This was back in the late eighties'.
Originally we were importing a system, but because of economic reasons, we later decided to manufacture everything locally. Our system consists of a pure reinforced aluminium foil and a polyester lining. The heating resistant wires are sandwiched in between. The pad gets installed between the underfelt (cotton underfelt only) and the carpet, and can be used for wall-to-wall carpets as well as loose rugs. Thanks to the aluminium sheet, the heat transfert is very swift and the surface of the carpet should be warm to the touch in 15 to 20 minutes. The pads come in different sizes and power outputs.

Underwood heating

Underwood heating is not really a system on its own. Undertile heating wires are used to this effect. The only difference is that the heating wires are laid in a different way. In these rooms, these wires have to cover a heating area of approximatly 90% to prevent unheated zones which could otherwise have expansion problems; the standard spacing between wires is 75mm, which is quite easy to do with our pre-cut spacers. Because of the organic nature of this material, the wood manufacturers recommend that the floor temperature does not exceed 28 ° C. To this effect, the system uses a fitted with a floor probe (heat sensor) which will be placed and buried in between two heating wires. The sealing procedure is exactly the same as for the undertile heating. We have gathered certain information that can be accessed by the following links with interest concerning wood and laminates.

Article from: www.heataroom.co.za