If you are thinking of installing your own electric underfloor heating, or you are having some installed and want to know more about the process, this article gives a brief guide to the fitting of the system, along with some handy hints and things to look out for.
How the system is installed
An electric system is fitted between the concrete or timber subfloor and the floor finish. Cables or mats can be laid in a format that suits the shape of the room and any fixed fittings within it.
Insulation is laid beneath the cables or mats to avoid any downward heat loss, while edge insulation stops any heat escaping into the walls.
The floor finish is then laid over the heating system. It is also possible to fit electric underfloor heating onto existing tiles and then lay new tiles on top. This should only be done if the existing tiles are sound and undamaged.
Each circuit within the heating system is connected individually to the main consumer board for safety, and the system is thermostatically controlled; in some cases there will be a thermostat to install in each zone of the house.
How long does it take?
A full installation could take between 2-4 days for an average sized system, but of course it depends on the type of system to be fitted and the amount of preparation work required.
Most matting and cable can be stuck to the insulation board; if this is prepared in advance the system can be laid very quickly. There is the re-laying of the floor finish over the heating and any alterations that may be needed to accommodate it.
Tips on preparation
One of the first things to consider is the type of flooring that is going to be fitted with the heating system. Certain flooring has heat tolerances that must be observed to prevent damage, and thick under-lays should not be used as they can prevent heat ingress into the room.
The system should be fully designed to fit each room before any work commences on the installation.
The cables or mats should be sized for watt output to ensure the system operates correctly and supplies the required heat; and they should also be sized to fit the shape of the room they are being installed in.
Any timber or wooden subfloors will need to be checked before the installation begins to confirm that they are structurally sound. Any loose floorboards need to be re-fixed and secured with plywood if necessary.
If the finished floor is going to be a tiled floor, it may be that the heating system is going to be laid in the tile adhesive. If you are using this type of system it’s important to make sure the subfloor is perfectly flat and even.
Timber may need to be primed before fitting the system to prevent moisture from the tile adhesive being absorbed by the wood.
The floor should be prepared by being thoroughly swept and cleared of any debris. The insulation board and the edge insulation can be laid in readiness for the heating system to be installed.
Things to look out for
Electric underfloor heating has a very low profile, most systems are 3mm or less, but it is worth checking that the system will fit and you will not need to raise the floors to an unacceptable level.
If it causes severe alterations to skirting and doors in the property, then perhaps underfloor heating isn’t the right thing to install.
Cables should not be cut once they have been sized and prepared for installation, it would compromise the integrity of the circuit and invalidate any warranty on the project. Some matting is supplied with the purpose of being cut to shape;this is an entirely different product.
Heat can have a damaging effect on timber and can cause it to crack, twist and warp; it is recommended that only timber with a moisture content of 10% or less should be used with underfloor heating.
Equally you should check the type of flooring you are using and it’s tolerance to temperature; some engineered laminate flooring may require the use of a ribbon cable system, which can operate at lower temperatures than other electric systems.
Can you do it yourself?
Electric underfloor heating can be laid as a DIY project; but it does depend on how much heating is being installed, and whether it is going into a new build or an existing property.
One of the easiest types of system to install is matting; it can be cut to shape and comes ready to stick on the insulation and subfloor. Once this is done it is just a case of laying the new flooring or carpet you have chosen.
Making the electrical connections and testing the supply however, can only be done by a qualified electrician, so there are still some jobs that require calling in an expert.
If the heating is intended to be the primary heat source for the house, it may be worth enlisting the help of experienced fitters to complete the job for you. This will ensure that it is fitted correctly and properly insulated so that it performs at its most efficient.
Electric underfloor heating systems can be installed into new builds and renovation projects equally as easily. It is something that can be undertaken by an experienced DIY enthusiast, with minimal help from a qualified tradesman.
The key to installing this form of heating is to make sure everything is fully prepared in advance.
The heating system should be sized and designed to suit the rooms, the floors should be clean, level and checked for structural integrity, and the type of flooring finish should be checked to ensure it can be installed with underfloor heating.