How to Install Underfloor Heating

Widely used in Scandinavia where outside temperatures are regularly freezing, underfloor heating is increasingly being viewed in Britain as a cost-efficient method of heating various rooms within a house where a comfortable temperature might be difficult to maintain, such as a kitchen or bathroom. The fact that is invisible and does not affect the clean-lined look of a room in the same way that a radiator would, in addition to lack of maintenance and care it needs in order to work effectively, also makes it an attractive option for homeowners.

There are two main types of underfloor heating for homeowners to choose between: wet or electric. Wet underfloor heating systems use warm water to create the heat, sourced from the central heating system, while an electric system uses coils powered from the mains.

WET

Wet heating systems see water pumped through pipes that are laid on the subfloor under the top surface of the floor. The system reduces the cost of water heating compared to systems that involve radiators, as it needs the water to be heated at a lower temperature to work effectively.

Wet heating systems are most easily installed where the floor can be pulled up and then put back into place – for this reason, it may be best suited to extensions or new builds. For the same reason, it may be best to restrict this type of system to ground floor rooms, but upper levels are certainly not off-limits.

PRE-INSTALLATION

Regardless of the type of underfloor heating system you choose or the type of floor you are installing it under, you should ensure that the rooms you're going to install it in are properly insulated so that the effect of the heat is not immediately negated. Ensure that the subfloor is clear of debris before you begin and that the joins between the insulation material are taped to prevent a loss of heat or screed (if you're using it) through them.

As already noted, a wet system tends to be more problematic to install than an electric system because of the general complexity of the system and because of the fact that it often means that the floor of the room has to be raised to accommodate it. Electrical systems are more compact and the raising of the floor (if required at all) will be minimal.

1. PULLING UP THE FLOOR

• The way in which you pull up the floor will depend on the placement system it utilises – most fall under the category of either tongue-and-groove or click in terms of the way the planks lock together.
• Tongue and groove flooring is nailed down through the tongue to connect the boards together, so the nails have to be pried out with a crowbar or similar tool to free the boards up. Begin (having removed the perimeter trim) with the row of the boards closest to the wall with top nails visible and ensure that you lever the crowbar against the subfloor once the first board has been removed if you want to reuse the flooring – this will avoid damage.

2. LAYING THE PIPES

An underfloor heating system should come with a guide, at the very least, that will enable you to ensure that you don't lay the pipes wrongly and end up running out of them before the desired area has been covered. If you have to create bends in the pipes yourself, you should be able to do it by hand, and whether you lay them in a spiral or from left to right across the room should depend on the manufacturer's instructions. Ensure that they are spaced evenly so that the heat spreads evenly when the system is in operation.

When positioning the manifold (where the system will be connected), fix it to the wall as close to the circuits as possible so it can be plumbed in the same way as a radiator. However, the final connection of the system to the main water supply and central heating network should always be performed by a qualified and experienced plumber unless you're completely confident in your ability to do it yourself.

One common problem that can occur at installation is the presence of air in the loops – this occurs when they are not flushed properly prior to being used for the first time. Each loop needs to be flushed individually by opening the valve that connects it to the manifold to ensure that no air is present in it.

An electric system sounds as though it should be relatively easy to install, given that it comes in the form of mats that need to be positioned underneath the areas to be heated. However, nothing that involves electricity is ever simple, and you should ensure that you take extra care in ensuring that the installation goes smoothly.

1. PULLING UP THE FLOOR

• The way in which you pull up the floor will depend on the placement system it utilises – most fall under the category of either tongue-and-groove or click in terms of the way the planks lock together.
• Tongue and groove flooring is nailed down through the tongue to connect the boards together, so the nails have to be pried out with a crowbar or similar tool to free the boards up. Begin (having removed the perimeter trim) with the row of the boards closest to the wall with top nails visible and ensure that you lever the crowbar against the subfloor once the first board has been removed if you want to reuse the flooring – this will avoid damage.
• Click flooring, often employed on laminate boards, is designed to be easy to put together, so it should be easy to reverse the process and remove it. Find the point at which the installation ended (usually a corner board) and pry that up. You can then go along the entire row adjacent to the wall and remove it in an entire piece, separating the individual boards by flipping them over and unclicking them from the bottom.

The two most common problems associated with the two systems have been covered already: air in the pipes of a wet system and faulty wiring in the electric system. Once the installation is complete, allow the screed to dry as instructed before turning the system on, as this might damage it and cause cracks to develop.

Otherwise, there is little aftercare that needs to be done to either type of heating system – this is one of the factors that make them such an attractive heating option. If the system stops working suddenly, contact the manufacturer, who may recommend that an electrician or plumber comes to look at it if the problem has nothing to do with the product itself.