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Joining Multiple Mats

UNDERFLOOR HEATING MAT INSTALLATION GUIDE

underfloor heating world living heat floor build up under tile and stone floors

Heating Cable Description

Underfloor Heating World (Living Heat) Heating cables are manufactured to comply with all EC European standards. All our Under floor heating conductors are made using a PTFE outer insulation, high tensile film screen, fully braided earth shield with a high temperature PVC (melt point 105°C) outer protective jacket; to form a high specification conductor heating cable. Heating cables are totally waterproof and incorporate an earth screen, making them perfectly suited for installations in wet areas. The resulting heating cable is extremely safe, durable and robust, with a thin profile of 2.2mm (single core) and 3mm duel core.

Heating cables are attached to a 500mm open weave mesh mat backing at preset factory spacing, to produce the Standard Output of 150w/m2 or 200w/m2 heating mats (150W/m2) and are ideally suited for the majority of underfloor heating applications. 200w/m2 units are ideal for use in high heat loss areas such as conservatories. Both 150w/m2 and 200w/m2 units are suitable for use as primary heat sources assuming a minimum of 70% floor coverage is achieved and suitable levels of insulation are installed.

Measuring Up Under Floor Heating Mats

It is important to measure the room correctly and avoid all permanent fixtures such as baths, showers, kitchen and bedroom units. It is important to avoid thermally blocking the heated area as this will result in localised heat build up and possible subsequent damage to the floor covering.
From the total area you are planning to heat deduct a further 10% to make an allowance for the perimeter.

For greater areas individual cable lengths can be joined in any configuration and connected in parallel. A contactor can be used where a single thermostat is required to control a total area of underfloor heating exceeding a 16amps. Alternatively consider the use of an additional thermostat. Underfloor Heating World, (Living Heat) thermostats are all rated at 16amps.
NOTE: Ampage loading is based on 230 Volts
If in any doubt contact for advice

Planning The Installation of Floor Heating Mats

The diagram below illustrates a kitchen floor 5m x 3.2m, which equates to a total area of 16m2. However, due to the fixed units and island the total usable area available to heat is reduced to 11.3m2. After deducting a further 10% perimeter allowance, this leaves a total heated area of 10.2m2. With this information the size unit selected should be a 10m2 (0.5x20m) units. The mat layout below shows a duel core mat, requiring connection to the electricity supply at one end only. The advantage of the duel core mat is by removing the need to design the layout to get the cable back to the original start point. The advantage of the single core is it is cheaper to purchase and also is thinner than the duel core unit so is easier to tile over and also requires less adhesive to cover.

under floor heating world living heat under tiles and stome hearting mat layout

Installation of Large Areas Using a Combination of 2 Heating Mats

Illustrated below is a 19m2 conservatory requiring a primary heating source. High output underfloor heatig world (Living Heat), 200W/m2 mats have been selected for the installation.

After making an adjustment for the conservatory corners of 1m2, a 10% standard perimeter allowance has been deducted to give a total heated area of 17.1m2: As 12m2 is the largest single mat size a 17m2 system is required which can be made up by combining 2 separate heating mats. A discount is provided when purchasing multiple mats.

Using the larger of the two heating mats, run this out from the termination point to the opposite end of the room: check the remaining floor area will accommodate the additional heating mat. Lay the additional heating mat and where necessary cut the mat backing to allow the floor heating cable to be run around fixed units, odd shapes, corners and previously laid matting. Remember, never overlap the heating mats as this will cause localised overheating, leading to eventual failure and invalidation of the manufacturer’s guarantee.

The thermostat sensor must be positioned centrally between the heating cable loops – see the Thermostat and Floor Sensor section below.

underfloor heating world living heat under tile and stone multiple mat layout

Floor Preparation

All floors should be suitably prepared prior to laying the heating mats:

Concrete sub-floors

If the sub-floor is a new concrete floor it should be allowed to cure naturally – as a guideline you should allow 1 week per 25mm but this is dependant upon weather conditions. If the finished concrete floor is not level then a thin layer of levelling compound should be applied to give a smooth and level surface.

Wooden sub-floors

Timber floors should be clean and level. Where necessary (especially if laying tiles on top of the underfloor heating), suitable plywood over-boarding should be laid, in line with the Tiling Federation recommendations.

Primer/Sealer

The use of a suitable Primer/Sealer is recommended by adhesive manufacturers on both concrete and wooden sub-floors to seal the porous sub-floor, prior to applying adhesives or levelling compounds. For more information on Underfloor Heating World (Living Heat), flexible tile adhesives, flexible grouts and flexible levelling compounds and primers please do not hesitate to contact ourselves.

Installation of Underfloor Heating Thermal Insulation

Where any underfloor heating is installed, heat energy will travel in both directions; down as well as up. Cement floors act as a heat sink absorbing this energy, creating a large drag on the performance of the flooring above. A high quality thermal barrier between the heat source and the sub-floor will significantly improve the performance of your floor heating, speeding up the initial warm up times and saving money on electricity costs. Underflooor Heating World (living Heat) offer a 6mm, 10mm and 20mm hard insulation boards for use under tile and stone floors. Please see insulations for more information or contact Underfloor Heating World (Living Heat)

Cutting and Shaping Under Floor Heating Mats

NOTE: Never cut the cable, this will invalidate the manufacturer’s guarantee: only the mat backing mesh can be cut. The heating cable should be no closer than 50mm from the walls and any other fixed obstruction. NEVER bury or try to hide the cable, if necessary start again. If you have ordered the wrong size of mat contact Under floor Heating World (Living Heat) and provided that the mat and cable have not been cut, laid or damaged in anyway, then it can be exchanged.
Before, during and after you must test the circuit using an ohmmeter to check the resistance readings and mark these down for later comparison. The correct ohms reading can be found on the information label on the heating mat / box.
Finally, to prevent potential damage to the heating cable, avoid excess traffic over the area until the final flooring is laid. Please see diagram below showing the cutting and laying of a heating mat.

underfloor heating world living heat under tile and stone heating mat cutting instructions

Laying Underfloor Heating Mats

Having now planned the layout of the heating mat to obtain the best fit within the floor area, the mat now requires to be stuck down to the underfloor heating world (living Heat) hard insulation boards if they are installed or wood/cement sub-floor if no insulation has been laid. To hold the mat firmly to the insulation or sub-floor, sticky strips have been manufactured onto the underside of the mat backing and can be seen with a smooth protective layer. Progressively lay the mat into the planned heated area, peeling the protective strips to expose the tacky surface of the tape, firming pressing the mat down as you go.

Thermostats and Floor Sensor

It is normal practice to site the floor heating thermostat within the room to be heated, however for bathrooms the thermostat is required to be sited outside.
The first 3 metres of black connection cables can be cut as required. The red/blue heating cable must never be cut or shortened.

If connecting your heating mats directly through a 16 amp thermostat:
A 16amp thermostat will control a maximum wattage of 3600 watts.
The maximum equivalent combination heating mats in the underfloor heating world (Living Heat) 150 range is (22m2)
The maximum equivalent combination heating mats in the underfloor heating world (Living Heat) 200 range is (17m2)

Contactors

A Contactor can be used where a single thermostat is required to control a total area of underfloor heating in excess of 3600 watts or a total loading exceeding 16 amps. The Floor Heating Contactor will control up to a maximum of 22,000 watts or 95 amps total loading: The total maximum area depends upon what size / rated contactor is installed.

Positioning The Floor Sensor

Having determined the size of the area to be heated and the correct size heating mat required; the next step in the installation process is to position the floor sensor correctly. Following the instructions provided with the thermostat, the probe should be fitted onto the floor , taped over the end (to protect the sensor from ingestion from tile adhesive or levelling compound) fixed into position with gaffer type tape and connected to the thermostat. The end of the probe should be directly between two pre spaced heating wires. Please see floor probe positioning below.

underfloor heating world living heat thermostat floor probe sensor positioning

Heating – Power Connection and Testing

To comply with current Part P Electrical Safety Regulations, it is now a requirement to connect your underfloor system via a fused spur (to isolate the system). The power supply should be from a safety contact breaker (RCD) to the thermostat – a qualified electrician would be able to advise you

Tiling Over Underfloor Heating

Once the heating mats/cables are laid, suitable protection boards should be used to prevent any possible damage during the tiling phase. A good quality rapid setting flexible tile adhesive should be laid evenly and spread in the same direction as the cables are running, in order to fully encapsulate the heating cable, leaving no air spaces.
NOTE: To avoid any potential damage to the heating cables that may be caused during tiling extra care should be taken not to damage the heating cables. Regularly checking the heating system is advisable during this stage of the instillation.
An alternative method of installation would be to pour a thin layer of flexible, self-levelling compound (sometimes referred to as latex) to cover the heating cable to give a level surface prior to laying the tile adhesive. Once the levelling compound has dried (12 – 24 hours) tiles can be laid as normal using a good quality flexible tile adhesive.

underfloor heating world living heat pictorial floor build up under tile and stone flooring

Switching on Your Heating System

Before switching on the under floor heating system allow a minimum of 3 days for natural drying of the tile adhesive and grout or levelling compound. It is recommended to initially operate the system for 1 hour, gradually increasing daily operation by a further 1 hour per day to full continuous use after 6 - 7 days.

Please note that all electric underfloor heating systems should be installed and connected to conform to current electrical legislation.
If in doubt, A suitably qualified electrician should be consulted prior to installing your heating system. A qualified electrician should make the final connection of the thermostat and commission the system: the installation will require a certificate to be issued by the electrician to conform to current electrical legislation and to validate your manufacturer’s guarantee.

Please feel free to email or phone us Monday - Friday 8am - 5.30pm and Saturday 9am - 1pm.

Electric Underfloor Heating World (living Heat) instillation guide for Heat Film under wood and laminate floors.

underfloor heating world living heat under wood and laminate heat mat carbon film floor levels

Junction Box Installation

If multiple mats are to be installed within one room or to one thermostat controller a junction box should be fitted below the desired thermostat location. This will allow all the connection tails be run back to one location ready to be wired up.

Laying 6mm soft thermal acoustic insulation underlay.
The sub floor must be level clean are suitable for the desired floor covering. Role your underfloor heating world (living Heat) insulation out over the sub floor making sure to cover the total floor area where the wood or laminate floor covering is to be installed including unheated areas. A contact spray adhesive can be used or a double sided tape to hold the insulation in place and aid the installer if required but is not a necessity. The diagram below shows the soft insulation being installed with the floor sensor / probe fixed in place.

under floor heating world living heat 6mm soft thermal underfloor heating insulation

Floor Sensor Installation

Once you have an idea of the mat layout within your room you will first need to install the floor sensor supplied with your thermostat. Cut a small channel into the insulation layer to allow the floor sensor / probe to be laid into. The channel should be located under a heated area, (heat mat to be laid over this channel in next stage), ideally ending under a the copper bus bar towards the outside of a centrally located heat mat.

Laying Underfloor Heating World (living Heat) film mats.

If you have requested a proposed mat layout from Living Heat you can simply hand this to the installer or follow the plan yourself. Alternatively make sure you unroll and identify each mat. Start at one side of the room rolling the mat from the non connection end of each mat (end with no connection tails), ideally towards the wall the thermostat is located. Each mat can be held in place by using a suitable adhesion tape such as gaffa tape along the ends and side of the mats.

underfloor heating living heat film mats laid over 6mm soft thermal insulation

Once the mats have been laid and fixed in place the connection tails should be run back to the thermostat / junction box location. The connection ends and cold tails can be pressed into the insulation by scoring the insulation and firmly pressing the tails / ends into the scored insulation. It is advisable to tape over the connection tails and cold ends to keep them held in place during the instillation of your wood / laminate floor. The diagram below shows the two ways mats can be connected beck to the thermostat. (Mats must always be connected in parallel never in series).

living heat underfloor heating world heat mat layout options

Installing the Vapour Barrier.

Once the underfloor heating world (Living Heat) mats have been laid and fixed in place the vapour barrier is ready to be laid over the top of all the under floor heating mats. The vapour barrier must fully cover all under floor heating mats, (it is not a necessity to cover the whole floor area only the actual heat mats themselves). If necessary the vapour barrier can be taped around the edges to hold it in place.

Underfloor heating world (Living Heat) heat film is designed for use directly under all wood and laminate floors. Please note however it is advisable to regulate the floor temperature using the floor probe with the thermostat set to floor only. This is because all wood and laminate floors have different max permitable temperatures and thus the flooring supplier should be consulted first to confirm the max permitable floor temperature the heating can be set to. This tends to be approximately 28oc for most wood and laminate floors.

In screed underfloor heating.

Before instillation can proceed, the sub floor must first be made suitable for receiving the intended screed flooring and a suitable insulation should be installed such as kingspan to fully insulate the heated floor area.

underfloor heating world living heat floor build up under tile and stone floors

1: Make sure the floor is level , free of dust and debris & suitable for the desired floor covering. Over un-insulated sub floors it is recommended to first install an additional minimum 10+mm suitable insulation layer, (Ideally 20+mm should be installed).

2: Time should be taken to plan the floor layout, please see the diagram below. The cable length on each system is set and the power output is also set to 17watts per linear meter. To use the heating as a primary heat source it is recommended to install 170w/m2 or more over a minimum of 70% of the floor area. To achieve this the spacing's between wires should be approximately 100mm , (this spacing can be reduced to increase the wattage up to 250w/per m2 if required ).

in screed underfloor heating world living heat under floor heating cable kit

3: Install the supplied fixing bar/spacing strips parallel to each other, across the two narrowest ends of the floor area approximately 10cm in from any wall or fixed/immovable object.

4: Starting at the power/thermostat position role out the cable to the nearest spacing bar. Starting at one end fix the cable to the bar through the clips and proceed to run the cable back and forth between the bars fixing the cable to the bars at approximately 100mm spacing's, Additional tape can used if required to maintain an even spacing between wires. (please note that the cable is a set length and should not be altered. The spacing between wires should be altered instead to make the cable fit).

5: Once installed the cable should be run back around the edge for the room to the start position ready for wiring.

6: If required the fibre tape can be used in place of the fixing bars. Often in small odd shaped areas the tape can offer more flexibility to the installer.

7: Before installation and before any screed is installed the cables should be tested for electrical resistance . If at any point during the installation procedure or floor cover fitting procedure damage is caused to the heating cable the cable should be re-tested and if necessary a repair kit used to repair the cable.

8: A 50 - 75mm screed should now be installed taking care not to displace the heating cables during instillation. (No heating cables must touch or overlap at any point). Once the screed has been installed the floor covering ie tiles can be laid as per the manufactures instructions.

Please feel free to email or phone us Monday - Friday 8am - 5.30pm and Saturday 9am - 1pm if you require assistance.

Living Heat Hard Insulation boards.

Living Heat, ‘Underfloor heating world’ hard insulation boards are designed for use under tile and stone flooring. Available in 6mm 10mm and 20mm depths.

living heat underfloor heating world hard insulation under tile instilation cross section

1: Make sure the sub floor is suitable for the intended floor covering. (Concrete floors are solid and sound and wood floors do not have excessive movement and are plied when necessary). Hard underfloor world insulation board will not make any unsuitable sub floor suitable. Note you will require sufficient insulation to cover the total floor area being tiled not just underfloor heated area.

2: We always recommend the use of a suitable acrylic primer to be applied over the floor prior to any tile adhesive being trawled over. This is to help with the adhesion of the adhesive to the floor and is good practice as part of a normal professional tiling process.

3: Using a shallow notched trowel spread a thin layer of 1 part flexible tile adhesive over the floor area you are working. Make sure not to trowel to large an area at once as if the adhesive begins to dry and forms a skin it will not adhere correctly to the hard under floor insulation boards.

4: Lay the hard underfloor insulation boards directly over the fresh 1part flexible tile adhesive using a large flat object / board to firmly press the boards down making sure to force out any trapped air pockets under the hard insulation boards. The boards can easily be cut with a sharp knife or fine tooth saw to achieve a full floor coverage.

Once the adhesive has fully dried, a suitable waterproof tape can be installed over all joints to provide a sealed floor but under normal conditions this is not necessary. The underfloor heating mats and subsequent floor covering (tiles / stone) can then be installed over using 1 part flexible adhesive as per manufactures instructions.

Please note that underfloor heating world hard insulation boards are not suitable for mosaic tiles or any tile less than 150x150mm in size. If you would like to fit mosaics over these boards a 10mm layer of self levelling must be installed over the boards prior to the mosaics being installed.

If underfloor heating world hard insulation boards are to be fitted under other floor coverings other than tile and stone flooring a flexible levelling compound must first be installed over the boards and electric under floor heating to a depth of 10mm prior to the floor coverings ie carpet and vinyl being installed.

If you have any questions or require further assistance on any living heat underfloor heating systems or ancillary products please do not hesitate to contact living heat. We are here to help and our advice is free.

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