Most common issues can be answered by the questions below.

Our technical staff are fully qualified electricians and plumbers and can offer expert advice on any additional issues you may have.

Need to talk to us? Call direct on: 01268 567016.

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Underfloor heating frequently asked questions

Below are a selection of questions we are regularly asked by our customers. They cover the most common queries we hear and should help out in most situations. If your question is not answer below feel free to call our highly experienced team, using the number at the top of the screen, who will be more than happy to help.

Our mats are for use beneath laminate/ engineered wood floors and some floated solid wood floors (check with manufacturer).

The flooring must be fitted 'floated' it must not be nailed or glued down. If using click together this is fine or if tongue and groove it must be glued along the joints. The biggest benefit of this system is that the wooden / laminate floor can be laid directly on top of the heating mat (there is no need to encase in tile adhesive or levelling compound).

What is the difference between the heating mats and cable systems?

Heating Mats:

Heating mats are the same cable as the loose cable kits (3mm loose heating cable rated @10 watts/m) already spaced out for you and attached to a fully adhesive mesh backing. Our heating mats come in 3 wattages:

  • 200 watts per square meter

    this is the most powerful type of heating mat. It can be used beneath tiled or stone floors and is recommended for high heat loss areas such as conservatories. It should also be used where laying onto a concrete floor when not using insulation boards. The maximum size of mat on 1 thermostat is 18m2

  • 150 watts per square meter

    this is a mid-range powered mat which is suitable for most applications which can be used as a primary source of heating beneath most floor finishes. It should be noted that finishes such as Kardean or Amtico have a maximum of 150w per meter. The maximum size of mat on 1 thermostat is 24m2

  • 100 watts per square meter

    This is the lowest powered mat which is suitable for taking the chill off cold tiles – it is not suitable for a primary heating source. The maximum size of mat on 1 thermostat is 30m2

Heating mats are for use on a finished subfloor such as concrete screed or plywood and we recommend they are encased in either a flexible tile adhesive (if laying tiles) or a flexible levelling compound if laying any other floor finish.

Heating Cables:

The loose heating cable is rated at 10 watts per linear meter and is the same cable used in the heating mats. The cable comes on a drum and spacing must be manually measured (full instructions on how to do this are included in the kit).

In Screed Heating Cable:

Must be encased in the finishing screed of the concrete floor (usually a minimum of 65mm as per Building regulations) with a minimum of 20mm of the screed above the cable. The same maximum outputs are recommended for the in-screed cable, that is, up to 200watts/sqm beneath tiles / stone and 160 watts/sqm beneath all other floor finishes.

How wide are the mats?

The mats are 500mm wide and come in different lengths to suit the size of the room you require. For instance if you require a 4m2 mat kit, it would come on a roll of 8m2 long by 500mm wide. This covers 4m2. You roll out the mat and cut it when you reach the end of the room then flip it over and come back the other way.

How high will the system raise my floor levels?

Our heating cables are 3mm thick, but you need to allow for your tile adhesive (5mm), your tile and any insulation board used.

What is the maximum wattage per meter square for my room?

Underwood – 140w per meter
Under Tiles / stone floors - up to 200w per meter
Under carpet or lino - maximum of 150w per meter

What wattage do i need?

If you would like to heat a standard room which is well insulated 150 watts or greater is required. If you are heating a conservatory, which is considered high heat loss or a room with lots of fixed furniture such as a kitchen then we suggest 200w. 200w by nature heats up faster than the 150w so if you can use it then you may as well have the most powerful.

Will the heating system be able to heat the room sufficiently ?

This depends on a number of factors including room height and insulations levels in floor and walls, but if insulation boards are used (blueboard or Heatstore tile backer boards for tiles – depron or blueboard for wood) then the system should heat the room.

The system always works best if used with suitable insulation boards as this prevents the heat from going downwards instead of upwards. We understand that not everyone has the floor height to install a board so in this case you could use Thermacoat thermal paint, which does not raise the height at all.

Can you connect up more than 1 cable or mat to a thermostat?

Yes, our range of thermostats will switch 15amps so any combination of mats or cables can be connected as long as the total load does not exceed this. If you would like to switch a larger area with 1 stat then you can use a contactor to switch the load, please call for more info on this.

When using more than two heating mat / cables to connect into 1 thermostat it may be a little tight to get all the cables into the thermostat terminals – in this case you can use a junction box to connect them which can be positioned on the wall behind a blanking plate or similar.

How hot does the floor get?

The floor will reach a temperature of approx 28c and will never feel too hot too touch

What size heating kit do i need?

You should aim to cover between 80-95% of the free floor space of the room. Covering less than 80 % of the FFS means you will end up with cold spots on your floor. We recommend that you measure the intended area to be heated and remove 10% of your total measurement to ensure that you don't order too much.

Are all wood and laminate floors suitable to use with our underfloor heating system?

These days most flooring manufacturers approve there flooring products to be used with underfloor heating systems, but we always reccomend you check with your supplier that your wood or laminate floor is suitable to use with our underfloor heating systems

What type of insulation should i use with underwood heating?

If you are using the underwood system as a primary heat source we always reccomend using our 10mm thick blueboard insulation, if you are using it as a secondary heat source our cheaper depron is suitable.

Is the underwood heating suitable for wet areas?

Yes - our system is suitable for wet areas and is fully 17th edition compliant, providing you follow the installation instructions.

What is the power output of the under wood heating system ?

Our mats are rated at 140w per m2.

What size are the mats?

The Heating mats are all 500mm wide and come in pre determined lengths from 1m2 to 12m2, eg: if you wanted to cover an area of 8m2 the mat would come 16 meters long by 0.5m wide, the mats can be cut and turned to suit any given floor space, this makes our system much more versatile than the old fashioned carbon film systems. (PLEASE NOTE DO NOT CUT THE CABLES).

Can i put furniture on top?

Yes most free standing furniture is fine to use, we dont reccomend installing it under any fixed appliances or fitted wardrobes etc, also thick rugs, dog beds etc can also cause localised heating issues.

Can i connect 1 or mats directly into the thermostat?

Yes you can wire 2 mats directly into the bck of 1 thermostat.

How do i keep the earth continuity?

The silver aliminium tape that comes with the kit needs to be placed across any mats that have been cut, this will ensure the mats continuity.

What is the maximum thickness of wood floor i can install?

18mm is the maximum thickness we reccomend to use to ensure you obtain the most from the system.

What is the total thickness it will raise my floor?

If you use our 6mm insualtion boards the total thickness will be 8mm as the heating mat is only 2mm thick.

Can the mats be cut?

The mats can be cut and turned to suit any given floor space, this makes our system much more versatile than the old fashioned carbon film systems. (PLEASE NOTE DO NOT CUT THE CABLES).

Why should i use warm water underfloor heating?

Warm water Underfloor heating has been around for over 2000 years, the concept behind Underfloor heating is very simple, using a much larger floor area the Underfloor heating pipes generate a much more evenly spread heat source, meaning the system can run at a lower temperature saving you costs on your fuel bills, Underfloor heating acts like a big evenly spread out radiator gently heating the room from the ground up, this requires approximately 20% less energy to achieve the same level of comfort experienced by a traditional radiator.

Do i need a special boiler?

No, nearly all types of boiler systems will work with warm water underfloor heating systems they just need to be able to provide enough power, its best to check with your installer who can carry out a on site evaluation to see if your boiler is suitable.

Is warm water underfloor heating better than conventional radiators?

There are many different advantages to using warm water Underfloor heating, the main one is the energy saved by heating a larger floor space at a lower temperature, other advantages include, more freedom of design from the developers point as radiators take up valuable wall space, also the convection style heating from a radiator systems means the warmest part of the room is the ceiling void, this obviously being a waste of heating and energy. As the warm water underfloor heating radiates slowly through the floor it gives off a much more even heat.

How does it work?

Warm water is circulated from the boiler to the electrically switched zone valves this is for all radiators and underfloor heating. When the room stat calls for heat the water then passes through the zone valves and then into the manifold where the water is circulated through continuous lengths of plastic pipe incased in the floor, which is run at a lower temperature (typically 50°C) whereas radiators are (70°C).

The Extension kits are designed to provide a solution for underfloor heating to single zone extensions + conservatories with a proposed concrete or sand and cement screed floor area up to 40m2, the manifold setup provides excellent water temperature control, blending the hot water from your heating system down to the safe temperatures used in warm water underfloor heating systems.

Our kits include the electrical controls and valves that enable your warm water underfloor system to operate independently from your existing heating system, in line with current building regulation part L.

Is warm water heating better than electric heating in new developments?

For new build extensions and new property developments where the sub-floor is not yet down, the warm water underfloor heating pipework can be incorporated within the cement screeded subfloor, this means that the pipework can be installed directly onto a foil faced insulation i.e. kingspan/celotex.

This means that no further insulation products are required saving both money and installation time. Another big advantage of warm water underfloor heating over electric systems in large areas is that most houses will only have a 100amp fuse rating meaning that a whole house system could possibly draw too much current.

Can a warm water underfloor heating system be fitted into any floor construction?

Our warm water underfloor Heating kits are primarily designed for fitting into a solid screeded cement based sub-floor. Timber suspended floors do not conduct heat as efficiently as screeded sub floors.

Lots of manufacturers use aluminium emission plates to try to achieve an even floor temperature. This is a very expensive way of installing underfloor heating in timber suspended floors, and at the end of the aluminium plate the temperature is not going to be very high. Clearly there should be a cheaper solution that works without using the very expensive aluminium plates, normally the first floor is usually a suspended timber floor and less heat is usually required as the first floor is supplemented by the heat radiating from the ground floor up.

Between the joists, a 50mm insulation board is normally installed and is supported by battens attached to the joists.

Our pipes are then clipped onto the insulation with our special pipe clips, the floor boards are laid on top of the joists, please note the recommend air space distance between the insulation boards and floor boards is 25mm . The joists will need to be notched where the pipe is run.

If your building is 20 years old or has a ground floor suspended floor we recommend getting the timber suspended floor to act as a screeded floor and it will give out more heat, we recommend air gap between the insulation and the floor boards should be filled with a light weight screeded mixture, this infill is normally required in most older type property's.

What are zones?

Zones are individual circuits of pipe up to a maximum of 100 metres of continuous heating pipe laid without joints each zone can be independently controlled via a thermostat or if required 1 thermostat can control everything.

If you require larger heated areas of 20m² or more our multi-zone manifold kits can be used, each zone is laid as a single circuit within the room up to a max of 100 linear metres of pipe; multi-zone systems for single rooms can be controlled using a single thermostat.

Multi -zoned manifold kits are also used to heat individual areas, pipework is laid out within the room as 1 or more circuits, with each circuit being no greater than 100 metres of pipe or up 20m² depending on the pipe layouts i.e. conservatories requiring closer spacing's.

Can i install warm water heating in my new conservatory?

Our warm water under floor heating is ideal for use in new build conservatories. To comply with the Part L of the new building regulations you must install controls that allow the switching off the underfloor heating when it is not required.

As most conservatories are built with a dwarf wall construction there is not much wall space left to integrate an effective central heating radiator system, making our under floor heating the ideal solution all round.

How do i work out pipe quantity?

To work out your require pipe length,  you will need to use the following calculation based on your required space spacing and area to cover. For example; Pipe spacing at 200mm centers and covering an area of 70m2 .

1000/200 = 5.0 linear meters of pipe
5.0 linear meters x 70m2  = 350 linear meters of pipe.

You would the round this up to the closest full length, in this case you require 400 linear meters of pipework to cover 70m2 @ 200mm spacings.

Do i need to use a notched trowel when installing tile adhesive?

Nearly all flooring adhesives are installed using a notched trowel. The size of the notching is important because it limits the amount of adhesive applied.Have your notch too large and you will spread too much adhesive. This can cause excessive indentations to show through sheet goods and trowel mark show-through or bleeding at tile joints. Always check the adhesive label for the recommended amount of notching.

What do you mean by working time?

Working time is the amount of time recommended for the adhesive to set before it is covered with the flooring. Working time is affected by temperature, humidity and porosity of the subfloor. Placing tile into the adhesive too soon may cause the tile to move and adhesive to ooze up between the tile joints. Placing flooring into the adhesive after the working time has passed will result in a failed installation as the flooring will not bond.

What does "dry to the touch" mean?

Dry to the touch means when you place your fingertips lightly on the adhesive ridges, no adhesive transfers to them.

I applied a levelling compound 24 hours ago, why isn't it dry yet?

There can be a number of reasons as to why this can happen. 90% of the time it relates to site conditions, such as room and product tempereture, lack of air flow, dew point etc. These conditions will have an effect on ALL types of levelling compounds overall.

When using levelling compounds and flexible tile adhesive, do you have to prime the substrate?

It is imperative that you prime the substrate prior to the leveller's application. We strongly recommend that you prime wood, non-prous and highly porous surfaces.

Why do i need to use flexible tile adhesive and flexible self levelling compound (latex) when i am fitting tiles over underfloor heating?

Due to the nature of underfloor heating, the tile adhesive and or levelling compound around the underfloorheating cables will be continually expanding and contracting. Over time this would cause a standard adhesive or leveller to crack and the tiles would crack.

How much adhesive or leveller do i need?

Find out more here.