Can you lay underfloor heating on tiles: How to Install Heated Floors Under Tile: a Definitive Guide

How to Install Heated Floors Under Tile: a Definitive Guide


Heated floors are best known for being used in bathrooms and kitchens, but heated flooring provides benefits for a variety of different tile installations. The properties of tile, marble, and stone floorings actually make underfloor heating systems more effective. Easy to install, economical to operate, and nearly maintenance free, heated flooring adds value to any tile installation and keeps energy bills lower and occupants happier.

The Benefits of Utilizing Heated Flooring Under Tile

Heated floors under tile provide many benefits to the rooms where they are installed. Tile has two special properties that make it uniquely suited for use with underfloor heating systems: high thermal conductivity and high thermal capacity, which means that tile heats up quickly and retains heat well. Heating up quickly means the heating system can be more responsive and can be adjusted more easily. Retaining heat helps lower energy usage and make people feel more comfortable.  

People generally feel hot or cold based on two things: the temperature of the air around them and the amount of heat radiating toward them. The Sun is a great example of heat that is radiated. Even when the air is cold, feeling the sunlight on your skin can warm you up. Using a radiant heating system under tile mimics that type of heating.

In a room with heated tile, the tile is able to radiate heat to anyone in the room. This creates a more even and comfortable feeling of warmth even when the air temperature is lower. When the entire tile floor has a radiant heating system, people feel more evenly warmed since the heat is radiated from all directions.

How to Install Heated Floors Under Tile

Not only are heated floors a great way to make any room more comfortable, they are also designed to be incredibly easy to install. Warmup offers 2 great solutions – DCM-PRO and StickyMat – to make underfloor heating installation simple and economical.

1. Measure the Room to be Tiled

Determine how much of the floor will be heated. Make a diagram of the room to ensure you have enough material. Don’t include permanent fixtures like vanities, toilets, showers, or tubs. The key is to determine how much floor area needs to be heated. As with most things, getting accurate measurements in this step can save you a ton of time later.

2. Acquire Materials and the Necessary Tools

Having all the needed materials and tools is essential to a smooth installation. Check that you have everything you need before beginning work:

  • Undertile Heating Mats according to measurements
  • Thermostat with floor sensor
  • Digital multimeter
  • Permanent marker
  • Measuring tape
  • Tape
  • Scissors

To obtain a quick list of the materials recommended for your radiant floor heating project, check out this instant pricing tool from Warmup.

3. Test the Undertile Heating Mats

Before installation, check that the floor heating system is in good condition. Using a digital ohmmeter, measure the resistance of the heating wires. The resistance should be within 10% of the resistance listed on the tag or in the manual for that model.

4. Inspect and Clean the Subfloor

For a good installation, the subfloor needs to be clean and free of debris. Remove any nails or sharp objects that can damage the underfloor heating system. If the subfloor is concrete, adhere a cork or synthetic cork underlayment to the subfloor before installing the heating system. The cork helps ensure that the heat from the underfloor heating system makes its way to the tile and is not wasted heating the foundation.

5. Install the Undertile Heating Mats

One of the easiest steps is actually installing the underfloor heating mats. Unroll the mat across the subfloor using tape or hot glue to hold the mat in place. Cut the mesh as needed to fit into the space but be sure not to cut the heating element. To fit the mat around tricky obstructions like columns and toilets, cut the wire away from the mesh and free form the heating element to fit.

6. Position the Sensor

Once the system is completely laid out and installed, place the sensor for the thermostat. Ensure that the sensor goes between the heating elements and does not overlap them. Weave the sensor into the mesh or use hot glue to keep it from moving around. Good placement of the sensor will keep the thermostat working just like it should.

7. Test the System Once More

Now that all of the components are installed, check that everything is working properly before installing the tile. The ohmmeter should still read that the system’s resistance is within range. If not, fix the problem now while everything is still easily accessible.

8. Connect the Thermostat

The system is now ready to be connected to the thermostat. Be sure to adhere to all local requirements. It is recommended that a licensed electrician makes the connection to the thermostat. Since underfloor heating systems may require significant amperage during warm up and to prevent tripping the thermostat’s GFCI, it is recommended that the underfloor heating system be put on a dedicated circuit.

9. Install Tile with Modified or Unmodified Thinset

Once everything is connected and working properly, the tile flooring can be installed. Check with the tile manufacturer to make sure that the tiles are compatible with underfloor heating systems, but this is usually not an issue since most tiles will work great with these types of heating systems.

To begin the tile install, apply a layer of modified thinset over the heating elements and mesh and install the tile. Install the tile as normal including using mechanical systems to prevent lippage. When the thinset has cured and the flooring is stable, your underfloor heating system is ready for use.

Warmup Offers the Best Radiant Floor Heating Solutions to Install Beneath Tile

With Warmup, your tile floors will not be cold any more. Warmup’s easy to install system makes adding underfloor heating simple and economical to any tile installation. To get a quote and learn more about their underfloor heating systems, reach out to Warmup today.



Underfloor heating with tiles: Your questions answered

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Underfloor heating with tiles is good for making your cold feet, warm
(Image credit: Getty Images)

Installing underfloor heating with tiles is a great way to heat your home while achieving the flooring finish you desire. 

Underfloor heating has been a popular alternative to traditional radiators for years thanks to its low running costs and constant comfortable temperature. 

Here’s our expert guide on everything you need to know about tiles and underfloor heating.

Does underfloor heating work with tiles? 

“Tiles are ideal for underfloor heating, particularly low temperature water-based systems, due to their superior longevity and thermal conductivity which ensures a fast heat-up time, making them a highly efficient choice,” says James Lloyd, specification consultant from Wunda Group.  

“There are a few different types of underfloor heating, but they all follow the same concept of heating the floor above, either by circulating heated water through plastic pipes or via a heated electric mat underneath the floor, some electric underfloor heating systems use infra-red to do this, but it’s very similar to the electric matting system.”

Tiles are ideal for underfloor heating, especially with wet systems that require the heating on a low temperature all day (Image credit: Wunda Group)

Can all types of underfloor heating be used with tiles? 

Both porcelain and ceramic tiles can be laid on top of wet and electric underfloor heating systems. “There are several different types of underfloor heating on the market and each has its own compatibility limits when it comes to the type of flooring material being laid on top,” explains Colin Lincoln-Evans, buyer at Tile Mountain. 

When buying tiles, it will usually specify whether it is suitable for underfloor heating or not. If it doesn’t then double check with the manufacturer.

“However, regardless of whether you’re installing underfloor heating with a wet system or for [electric underfloor heating installation], it’s important to always use a flexible adhesive such as Mapei Keraquick [like this from Tile Giant] and ensure you have the right sub-floor for installation.”

Can underfloor heating crack tiles?

“Ensuring the UFH is commissioned correctly and using a flexible adhesive and grout should ensure that the grout and tiles don’t crack,” explains Colin Lincoln-Evans. 

To further reduce the risk of the flooring cracking when laid on top the underfloor heating system, a level floor is essential. 

“In an ideal world, underfloor heating systems of all types would be installed atop of a fully cured, fully level concrete screed that is between 60mm and 75mm thick,” Colin continues. “If this isn’t possible you should take the greatest effort to ensure that the sub-floor substrate is suitable for your particular underfloor heating installation.  

“Making sure that your sub-floor is level is always a good place to start – using levelling compound ahead of installing underfloor heating will help prevent cracking and alleviate any cold/hot spots, as well as disperse the heat evenly and also protect the kits during installation. If installing over non-tongue and groove floorboards or joists then you will need to use a backer board, again, making sure that it is suitable for your type of installation. Once these substrates are in place then you can install the tiles as normal.”

The sub floor needs to be nice and flat for underfloor heating installation and tiling (Image credit: Getty Images)

What are the best tiles for underfloor heating? 

“Most types of porcelain and ceramic tiles are suitable for use with underfloor heating, as are natural stone tiles including limestone, marble, slate, terracotta, and quarry tiles,” says Tile Mountain’s Colin Lincoln-Evans.  

“Tiles are the most thermally conductive floor finish, but there are many other everyday options that work well including carpet, engineered wood, laminate and vinyl,” adds James Lloyd from Wunda. “Wood effect porcelain tiles gives the ‘best of both worlds’, as you can have the appearance of wood with the high heat output and fast heat up times of tile.”

How to remove tiles with underfloor heating underneath

While it can be difficult to remove floor tiles without damaging the underfloor heating system underneath, it isn’t impossible. Hand tools are recommended to first remove the grout before lifting the tiles, but this process is time consuming and the risk of causing issues with the underfloor heating below is very high.

Make sure you pay particular attention to not damaging the underfloor heating manifold or any wiring going to the underfloor heating thermostat.

Can I lay Karndean, wood, carpet or other materials on top of tiles with underfloor heating?

Laying a different flooring type on top of tiles above the underfloor heating system is not generally advised, but if you’re looking to change the style and don’t want to risk damage by removing the tiles, a thin laminate would be the best option. Some of the residual heat from the tiles should still penetrate through to the top layer, but the effect will be reduced and slowed.   

“As a general rule, solid wood flooring isn’t suitable for use with underfloor heating, regardless of whether it’s a ‘wet’ system, a mat kit or cable kit, unless expressly stipulated by the manufacturer,” says Colin Lincoln-Evans from Tile Mountain. “Engineered timber however is generally suitable given that is less prone to movement and expansion when subjected to heat and humidity.”

You can read more information about different materials with our guides on underfloor heating with carpet and wooden flooring with underfloor heating.

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Assistant Editor Amy began working for Homebuilding & Renovating in 2018. She has an interest in sustainable building methods and always has her eye on the latest design ideas. Amy has interviewed countless self builders, renovators and extenders about their experiences for Homebuilding & Renovating magazine. She is currently renovating a mid-century home, together with her partner, on a DIY basis, and has recently fitted her own kitchen.



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laying technology of electric or water floors

Underfloor heating is widely used in private houses and apartments. Often it is laid in rooms where tiles are used. Consider the features of laying tiles on a warm floor.

Why tile on underfloor heating?

Tiles are often used together with underfloor heating. Why not use some easier-to-install material (laminate, parquet)?

  • Wet rooms – tile is the most common flooring option in the bathroom and toilet. We often walk barefoot in these rooms, so we usually want to have a comfortable floor temperature there.
  • High thermal conductivity – Ceramics and porcelain tiles have a high thermal conductivity compared to wood. This allows them to quickly heat up when the floor heating is turned on.

Don’t confuse comfortable and warm floors. The first option does not fulfill the task of compensating for temperature losses, so its average temperature is usually low – 22-24 degrees. A warm floor can heat up to 30 degrees, so it can act as an additional source of heat in a house or apartment.

Types of underfloor heating

Let’s consider the main types of floor heating equipment in order to understand the specifics of laying tiles on them.

  • Water (liquid) – pipes are laid in the floor in which the coolant circulates. The system requires a pump to operate. Underfloor heating pipes have a diameter of 16 or 20 mm, so hiding them in a layer of tile adhesive will not work. Usually, communications are placed in a screed; for this, its thickness must be at least 85 mm. Liquid systems are forbidden to be used in apartment buildings, since the removal of coolant from the heating system is not allowed.
  • Electric underfloor heating consists of a heated cable 5 – 8 mm thick, which is attached to a polymer mesh. The cord is laid in a wave or spiral. The thickness allows you to lay the equipment without a screed, tiles can be laid directly on the warm floor.
  • Film floor is actually also an electric floor, but due to differences in design, it is usually placed in a separate category. The mats consist of a polymer sheet on which copper and carbon heating strips are fixed. This coating option is laid without a screed, but cement mortars cannot be glued to it. In most cases, heating mats are used in places where a cable or water floor cannot be used.

Film flooring is often installed under coverings that are not bonded to the subfloor (parquet, laminate).

Under tiles or porcelain stoneware, you can use liquid or electric underfloor heating, the film version will not work here. At the same time, for an apartment building, there is actually only one option left – a floor made of a heating cable. We will focus on him.

Stages of work

Preparation of the base

The surface must be cleaned of debris, damage and cracks repaired. If the ceiling has drops, then you must first fill the screed and bring the floors in all rooms to the same level.

If the repair is in a city apartment, then the floor level in the premises should not be made higher than the level in the entrance. Otherwise, we will get a high threshold. Read more about errors when leveling with a screed in a separate article.

The surface must be dedusted and primed for subsequent application of tile adhesive. If a warm floor is laid in a damp room, then at this stage the rough base must be treated with waterproofing mastic.

Underfloor heating

Plan the placement of mats at the design stage. It does not make sense to place the cable in places where a person does not come into contact with the floor (under the bathroom). It is also not recommended to lay out the heating cord under furniture, as a strong increase in temperature can lead to damage to wooden products.

  • Mats should not be placed close to the wall, they should be 5 cm away from them. The distance to other heating devices is made at least 10 cm.
  • An important element of a warm floor is a temperature sensor, you need to think over a place for it at the planning stage. This element should be located 0.5 m from the wall, it is placed in a corrugated cover, at the end the tube is closed with a plug.
  • Since the tube increases the thickness of the warm floor, a streak is made under it. If waterproofing was done on the floor, then the recess must also be treated with mastic.
  • Rolling starts from the place where the temperature sensor is located. The cable itself cannot be cut; trimming is done only along the grid. The floor itself does not need to be glued to the base, but the grout must be sealed with tile adhesive.
  • At the final stage of installation, the floor is connected to a thermostat. It is important to check the operability of the equipment – to conduct a test run.

If the floor is not checked before tiling, then after all work is completed, the damage will not be repairable.

Laying the preparation layer of adhesive

At this stage, the sequence of work may differ depending on the approach. Sometimes tiles are immediately placed on underfloor heating, but there is also an option with an additional adhesive layer. This procedure will protect the heating cable from damage by a spatula.

To create a preparatory layer, dilute the tile adhesive and apply it evenly on the substrate. The thickness should not be very large. Further work can be started in a day.

Laying the tiles

This step also starts with laying. It is advisable to first make a drawing in order to understand how the elements will be located. The main task is to avoid short cuts in visible areas. Read more about layout rules in a separate article.

If a tile adhesive underlay was made, it must be primed, and work should be started after the primer has dried.

The adhesive can be applied to floors, tiles or both. In work, you should use a regular spatula and comb. The first allows you to apply the solution to the surface, the second removes excess.

The furrows from the comb must run horizontally or vertically, but not in an arc. In this case, there will be little glue left on the corners and the tile may break off. Read more about other errors when laying tiles in a separate article.

Tiling starts with whole elements, cut tiles are inserted at the end. For cutting, you can use a tile cutter and nippers for ceramics.

The process of laying tiles on the floor is discussed in more detail in a separate article on our website.

Grouting

Grouting is done to protect the joints from moisture. Also, the application of the fugue allows you to give the gaps between the tiles a certain color. Grouting starts one day after laying the tiles. Before this, you need to wash the floor well so that the remains of the solution do not get into the fugue. The seams are embroidered so that there is room for the mixture in them.

Puffer is kneaded in small portions and rubbed in with a rubber spatula or grater. It is important to wash off the composition in a timely manner with a colorless detergent. In general, the process does not differ from laying tiles on other types of coatings, you can read more about this at the link.

Underfloor heating can only be switched on 3-4 weeks after completion of work. Heating in the early stages can cause the tile adhesive to dry out prematurely because of this, the tile will not adhere well to the base and may fly off.

which is better to choose and how to install

Electric underfloor heating is a popular solution for heating residential premises. They are used both in private houses and in apartments, because they are allowed to be connected to existing wiring systems in apartment buildings. The warranty period for underfloor heating from many manufacturers is very long – 10, 15 years or more. For example, the Russian manufacturer Teplolux gives a lifetime warranty on some of its products.

Electric underfloor heating will be a great addition to the main heating system in the house. However, it can also be used as the main source of heat, for this it is necessary to arrange heating for at least 80% of the surface. The advantage of a warm floor is that the air in the room warms up evenly due to the fact that the heating comes from below, and the heating elements are distributed over the floor area.

Most mechanical or electronic thermostats are suitable for controlling the heating element. For example, automatic programmable thermostats from the Teplolux company allow you to set the time to turn on and off the heating, and the model that works via wi-fi, control it from a distance.

Which is better to choose an electric underfloor heating under tiles

Electric heated floors are divided into two large groups: cable and infrared. For cable floors, the heating element is a cable, and for infrared floors, composite rods or a film with conductive carbon strips applied to it. Cable floors are supplied either as the cable itself or as a heating mat. The heating mat is a cable attached with a certain pitch to the base. The basis, as a rule, is a fiberglass mesh or foil. Before buying, you need to check with the manufacturer or seller with which coating this or that product is combined. For tiles, both versions of cable floors are used (except for foil ones, since their installation does not imply strong adhesion of plates, glue and base), as well as rod ones. Infrared film is used with tiles quite rarely.

Warm floors “Teplolux”

Advertising. Teplolux Group LLC LjN8K1Gvj

Heating cable. This is an ideal option if the renovation of the premises starts from scratch, or a major overhaul is planned. To mount such a warm floor, you need to perform a screed and lay the cable in a layer of mortar 3-5 cm thick. The advantage of the cable is that the total heating power can be adjusted by the laying step. For example, for a bathroom with high humidity, you can lay the cable more tightly and thereby increase heating, and for a small room without a balcony, on the contrary, take a step wider and reduce power. The recommended power for living rooms in the presence of the main heat source is from 120 W / m2. For bathrooms or cold rooms – 150-180 W / m2. We recommend considering two-core cables due to the relative ease of installation compared to single-core cables.

Electric underfloor heating. Photo: “Teplolux”Electric floor heating. Photo: “Teplolux”Electric floor heating. Photo: “Teplolux”Electric floor heating. Photo: Teplolux

Heating mats are laid in a thin layer (5-8 mm) of tile adhesive. Thus, the installation of the mat is easier than the installation of the cable, and most importantly, it almost does not increase the height of the floor covering. If you want to lay the mat at an angle or fit the shape of the area, it can be cut without affecting the cable. The optimal power of the mat is 150-180 watts per 1 m 2 : this will heat the room evenly and quickly.

Rod floor. Heating elements are rods made of composite materials (the most common rods based on carbon) attached to the mat with a certain pitch. Manufacturers of such floors claim that they are very economical, as they stop using electricity when the rods are heated to a certain temperature. Mount the core floor both in the screed and in the tile adhesive.

How to properly lay an electric underfloor heating under tiles

We will analyze the process of laying an electric underfloor heating using the example of Teplolux products. This is a sought-after Russian manufacturer, its underfloor heating kits have been awarded many prestigious awards.

First you need to decide whether you are using a cable or mat. It depends on whether you have to perform a floor screed. In the case of a cable, the “pie” should look like this:

  • primed, even concrete base;
  • PE foam insulation layer;
  • heating sections – cable;
  • cement-sand mixture screed 3-5 cm;
  • tile or porcelain stoneware flooring.

If you are laying a mat, there will be a layer of 5-8 mm thick tile adhesive instead of the screed.

Tools needed for the job:

  • Resistance tester.
  • Perforator.
  • Square.
  • Screwdriver.

Tanks for building mixtures.

The Russian manufacturer Teplolux gives a lifetime warranty on some of its products. The Russian manufacturer Teplolux gives a lifetime warranty on some of its products.

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Draw a floor plan of the room

You should, if possible, have an exact idea of ​​where stationary furniture without legs will be located, such as built-in wardrobes, kitchen sets or, for example, a washing machine. Laying underfloor heating under such furniture is not recommended.

Pay attention to the subtleties of styling. For example, the temperature sensor should be 50 cm away from the wall, and the cable should not be closer than 10 cm from walls with radiators and 5 cm away from walls without heaters.

Preparatory stage: a place for a box and wires

A strobe (20 × 20 mm) is to be made in the wall for the wiring of the thermostat and the device box itself. As a rule, it is installed at a height of 80 cm from the floor. If you are laying a warm floor under the tiles in the bathroom, then you should not bring the thermostat into the room – fix it outside. To make room for the thermostat box, take a drill bit. It is not necessary to lay “bare” wires in the groove, they must be placed in a corrugated tube. The thermostat is powered by 220-230 volts.

Floor preparation

Clean the concrete base of the floor, roll out the thermal insulation rolls – it is necessary for the efficient operation of the underfloor heating. Experts recommend using polyethylene foam as thermal insulation. A mounting tape is distributed over the thermal insulation. At Teplolux, for example, it comes with a cable.

Laying the heating cable

The cable is serpentine. The step must be calculated by yourself, manufacturers, as a rule, describe in detail in the instructions how to do this. The smaller the pitch, the higher the power per square meter. It must also be remembered that there are limit values ​​- they must be obtained from the manufacturer. Many manufacturers recommend not to step less than 5 cm. The distance between the turns is calculated using the following formula:

100 * (heated area / length of one section) = laying spacing in centimeters.

See documentation for section length.

Before laying the section, it is necessary to check its resistance, it must match what is indicated in the complete papers from the manufacturer. The turns of the cable during measurements should not intersect, kinks and excessive tension should be avoided.

The mounting tape has special tabs that secure the cable. The installation wire is connected to the heating section using a coupling, the connection and grounding diagrams must be viewed in the manufacturer’s documents.

If you decide to install a heating mat, you should also measure the resistance, but you do not have to calculate the pitch, fix the tape yourself and lay the cable.

Production of underfloor heating “Teplolux”. Photo: TeploluxProduction of underfloor heating Teplolux. Photo: TeploluxProduction of underfloor heating Teplolux. Photo: TeploluxProduction of underfloor heating Teplolux. Photo: “Teplolux”

Temperature sensor

The temperature sensor should be half a meter away from the wall on which the thermostat is placed. The sensor is placed in a mounting tube (it performs a protective function) and closed with a plug. The tube must be fixed between the threads of the heating cable at an equal distance from them using mounting tape.

Thermostat

After the place for the thermostat box is ready and the wires are connected, do not forget to de-energize the wiring. The thermostat has several outputs in which you need to connect the wires. Refer to the instructions for your device to connect everything correctly. The rear cover of the thermostat is placed in the junction box and fastened with screws, and the front panel is put on top. After that, you can check the health of the system and connections.

Electrical work should be left to a professional if you are not qualified to do it.

Laying the screed

This step is relevant for laying the heating cable, for heating mats it is optional. The screed is carried out using a cement-sand mixture, its thickness is 3-5 cm. The drying time varies depending on the properties of the particular solution, temperature and humidity, but usually it is at least a week.

Laying decorative flooring

Laying tiles or porcelain stoneware on underfloor heating is not much different from conventional laying. Care must be taken not to damage the wiring with a spatula. This is especially true in the presence of a mat embedded in the adhesive layer.

Frequently Asked Questions

What is the best thing to do when laying electric underfloor heating under tiles?

– The main danger when laying a warm floor with your own hands is the connection of a thermostat.