Debi Boulton, brand manager of Dunlop, discusses how under tile floor heating isn’t just a job for the professionals anymore and explains how advising professional builders can give builders’ merchants the upper hand and gain repeat business.

With homeowners looking to progress up the property ladder and make the most of the booming house market, home improvements are becoming a hot topic in the trade. However, rather than sticking with the old, homeowners are deciding to invest in their properties through home improvements to increase their chances of catching a buyer's eye in a busy and competitive housing climate.

With that in mind, it is no wonder that under tile floor heating has grown to become more of a popular commodity, which is no longer just a job for the specialists; it’s now more commonplace for tradespeople to do everything, from laying the under tile floor heating system to tiling over the top – which is where merchants and their product knowledge come into play.

What are the benefits?

There are several benefits to under tile floor heating compared to the use of conventional radiators:

  • Space and economics – every square metre of a home can be fully utilised and the cost of an under tile floor heating system is very similar to a radiator system
  • Hygiene – no dust and the under tile floor heating will help to reduce house dust mites, as moisture content is too low for them to thrive, which is a benefit to asthma sufferers
  • Aesthetics and labour saving – homeowners can design their home to suit their needs rather than that of a heating engineer’s. Cleaning floors is made easier and wet floors dry very quickly – preventing discolouration of paintwork, peeling of paper etc.
  • Silence and comfort – under tile floor heating will provide the highest comfort levels at an even temperature throughout. Compared to radiator systems, there is no noise, and no annoying ticking as pipes expand in floor voids
  • Ease of control – some systems can be practically self-regulating.

Top tips

When it comes to tiling over under tile floor heating, we certainly know our stuff, and passing on our knowledge to merchants and their staff is what we’re all about. As with all tiling jobs, the products used from preparation through to the finishing touches will always differ for each individual job. It is therefore essential that the correct products are recommended to customers when tiling on under tile floor heating as the implications of using the wrong products can be costly. In this case, the guide that we advise customers to stick to is to make sure that the products used are ‘flexible’.

Another tip we recommend merchants to pass onto customers is that when purchasing an under tile floor heating system, test, test, and test again. Test the system when taking it out of the box, test the system once it’s been laid, and finally, test the system once it’s been tiled over. Ensure the system is installed in accordance with national building and electrical regulations and connected by a qualified electrician.

Tiling onto under tile floor heating

Ensure that the existing floor is flat and smooth. The first stage, before laying and setting up the under tile floor heating system, would be to prime the floor. If required, level the existing floor using a suitable Dunlop floor levelling compound. It is recommended that suitable insulating tile backing/thermal boards are laid onto the existing floor prior to setting out the under tile floor heating. The boards will help to direct the heat upwards instead of being absorbed by the substrate beneath and by priming the floor, the flexible adhesive will bond to the substrate rather than dust. The boards should be installed in accordance with the manufacturer’s recommendation and, if required, may also be bonded to the existing floor using a suitable Dunlop tile adhesive.

For the next step, after the under tile floor heating has been laid, customers can either apply an adhesive directly over the cables or use a levelling compound. There is no right or wrong process, although the benefit of customers buying both products would ensure that tiling would

have a more professional finish and obviously be an added benefit for merchants’ tills. If the customer decides to use a floor leveller, a flexible self smoothing levelling compound that can be applied at a bed depth of up to 50mm is preferable due to the nature of the job, with every care taken not to damage the cabling when working.

When the floor is ready to be tiled, it is not only important to select an adhesive that is suitable for the tile type but also one that is flexible, to cope with the variable temperatures caused by under tile floor heating. Movement beneath the tiles through thermal expansion and contraction and any deflection within the floor can result in the tiles becoming damaged or de-bonded. Therefore it is essential to ensure that the floor is sufficiently rigid and stable enough to support traffic as well as ensuring that the tiles are fully supported by the tile adhesive, as voids will also be points of weakness under load. Using the correct tile adhesive is also essential.

Commissioning the heating system should be carried out in accordance with the system supplier’s recommendations.

Again, when it comes to grouting the tiles, customers will need to use a flexible grout and then allow for 14 days before the floor is brought back slowly up to its operating temperature, if practical at a maximum rate of 5°C per day.

Dunlop’s recommendations

With all our products, each pack is clearly labelled with colour-coded icons for merchants and customers to identify which products are suitable for the job in-hand, as well as a clear product description. In preparation, we’d recommend our Universal Bonding Agent when priming the floor and for levelling, our Thick Bed Floor Leveller comes up trumps when used on under tile floor heating. There are two adhesives, which are most suitable for tiling on under tile floor heating - the Set Fast Plus Floor and Wall Tile Adhesive as well as the Large Format Natural Stone Adhesive. And last but not least, our Flexible Floor and Wall Grout will give customers peace of mind that not only does the job look good, but also it is robust enough to maximise the lifetime of the tiled surface.

Debi Boulton is brand manager at Dunlop.