Adam is the founder of Circa Installations & the Floor Heat Store with years of experience in installing underfloor heating.
Ask most people why they've chosen to install underfloor heating and you'll find it's because it is an energy efficient, safe and reliable heating system. In this blog post, I will share some of the top tips on how to install underfloor heating that I have learnt during the years as an underfloor heating installer. Whether you're a professional installer or an enthusiastic DIYer, I hope you'll find these tips useful.
Modern underfloor heating systems are divided into wet (or "hydronic") and dry, or electric. Dry systems are generally simpler and they run on mains electricity, whereas wet systems use a loop of pipes carrying water and are connected to the boiler or another heat source. In terms of issues with installing underfloor heating, a competent DIYer shouldn't have any major problems installing either system, though wet systems may be more complex.
Your choice of system is affected by where it's going to go to. New build projects are well suited to wet systems as underfloor heating pipe is often embedded in new concrete floors, whereas the cables and mats that make up electric systems can be laid on top of the subfloor before being covered with whatever flooring has been chosen. With tiled floors, the cables will be sealed in tile adhesive. Wood and laminate flooring, vinyl and carpets can also be used with the system.
If you are not sure which type is best suited to your project, contact a qualified electrician or Warmup for advice on suitability of a chosen system and to discuss any remedial works which should take place before your installation commences. Warmup as the world’s best-selling floor heating brand is a great choice for the system. You should beware of cheaper alternatives made from low-quality products and always ensure that you are buying a genuine product from an authorised Warmup reseller to ensure the best value for money.
Modern pipes used in wet systems are tough and durable. However, clean the subfloor thoroughly before installation and the laying of the underfloor heating pipes to get rid of any jagged edges that could damage them. You may need to lay a damp-proof membrane on the subfloor before installing the insulation layer that comes with the kit.
The pipe attaches to a simple set of units that hold it in position so that each loop is at the specified distance - generally between 200mm and 250mm apart, depending on the type of floor. The maximum length of pipe that can be used in any one room is about 100-110m.
With wet systems, the manifold - the unit to which the pipe loop is connected in a particular room - should be the first thing that's installed. You'll need to account for the weight of the unit and for the pipes that are eventually connected when choosing a mounting site.
With electric underfloor heating, it's necessary to get a qualified electrician at least to make the mains connection in order to comply with BS7671- 2008 and current IEE wiring regulations.
One of the most important things to consider is the kind of finished flooring that will be laid over the system as some floor covers have a top temperature restriction. Vinyl floors have a maximum temperature limit of 27°C degrees, as do carpet, laminate and wood floors.
I can’t emphasise enough how important installing Warmup insulation boards is. A lot of people try to save money and not bother with underfloor insulation, but it has massive benefits from decreased heat-up time to energy savings and lower running costs in the long term.
Planning is essential so measure out the area and plan for the installation carefully. My tip is to take your time with this as it will make for a much quicker installation in the long run.
Make sure to consider all the fixtures and fittings that are going to be installed. For example, with a bathroom installation your toilet pans, pipe work for heated towel rails and radiators have to be fixed to the floor. All this needs to be taken into account when installing the system as to avoid damage to the heating wire when the above are being fitted. Also, ensure your existing subfloor is free from dust and dirt and, if it's a wooden subfloor, check that there are no squeaky floorboards as fixing this afterwards will not be easy.
It is very important that you test the system before and after all stages of the installation. If you are unsure, just ask your electrician to do this before the final floor covering goes down.
Also remember that all Warmup systems come with a SafetyNet™ Installation Guarantee which means that if the heater is damaged during installation, it will be replaced free of charge giving you that extra piece of mind when installing the system.
When laying underfloor heating mat, lay the mat with wires facing down to the subfloor and the mesh up this will give greater protection to the heating wire during installation. Always follow manufacturing guidelines or seek professional advice if in doubt.
And finally, if the final floor covering is going to be tiles or ceramic, I would always recommend using a flexible self-levelling latex or a flexible tile adhesive to cover the underfloor heating mat with a scratch coat as this helps the tile installation.