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ThermoSphere Underfloor Heating Membrane / Cable

(3 customer reviews)

£15.00£745.52 (inc VAT)

Please note: The membrane and cable are supposed to be ordered as individual items. They are not sold in kit form.



The ThermoSphere Underfloor Heating Membrane & Cable system (previously known as Vario Pro) is a system that combines an uncoupling membrane with a electric heating cable. Please note that the membrane/cables are supposed to be ordered as individual items.

The ThermoSphere Underfloor Heating Membrane is a waterproof, polypropylene membrane matting with square shaped dimples that are designed to form channels that hold the ThermoSphere Electric Underfloor Heating Cables at variable spacing depending on the required heat output – 2 dimples apart equates to a 195W/m² output, 3 dimples equates to a 135W/m² output. This matting has an anchoring fleece on the underside to provide a strong bond to the substrate below and is designed to be used with tile adhesive. This matting forms an uncoupling layer between the tiles and the substrate – this neutralises the stress caused by different rates of expansion and contraction in a tiled floor and minimises the risk of tile delamination and cracking. This matting can also be used with the Comfortzone Electric Underfloor Heating Cable, a budget alternative to the ThermoSphere Underfloor Heating Cable.

The matting is also available with a self-adhesive backing – this cuts down on additional costs for adhesive to fix the matting and makes it quicker and easier to install. Please note this is only suitable for flat, level substrates that are dry and free from dust and debris.

The ThermoSphere Underfloor Heating Membrane provide a number of additional benefits – the studs and fleece backing in the membrane allow water vapour beneath it to escape effectively. This means you can save time by tiling over a substrate that is not fully cured. The stud structure also provides efficient load distribution for the tiled surface by transferring the load to the subfloor evenly – this reduces the risk of cracks so is recommended for high-traffic areas.

The ThermoSphere Underfloor Heating Cable features a Twisted Twin Conductor cable design that neutralises cable stress and results in a supple, durable, quality cable. This cable is designed for installation into the ThermoSphere Underfloor Heating Membrane, and can be laid out in a completely flexible, custom layout that best suits your walkable/exposed floor area, as it can be laid around fixed items such as toilets, cabinets, baths, etc. We recommend using a ThermoSphere Thermostat with this cable. ThermoSphere Underfloor Heating Cables are available in the following sizes to suit a range of area sizes, as shown below. 2 dimples apart equates to a 195W/m² output, 3 dimples equates to a 135W/m² output. Please note that laying the cable 2 or 3 dimples apart changes the area coverage of the cable length, which is why there are two area coverage figures for each cable.

Cable Length in metres
12 metres
18 metres
25 metres
31 metres
37 metres
42 metres
50 metres
55 metres
61 metres
75 metres
90 metres
100 metres
125 metres
150 metres
175 metres
200 metres
Area Coverage (3 dimples, 130W/m²)
1.15 m²
1.73 m²
2.31 m²
2.88 m²
3.46 m²
3.90 m²
4.62 m²
5.10 m²
5.77 m²
6.92 m²
8.32 m²
9.23 m²
11.54 m²
13.85 m²
16.17 m²
18.46 m²
Area Coverage (2 dimples, 195W/m²)
0.8 m²
1.15 m²
1.54 m²
1.92 m²
2.31 m²
2.60 m²
3.08 m²
3.40 m²
3.85 m²
4.62 m²
4.99 m²
6.15 m²
7.69 m²
9.23 m²
10.78 m²
12.31 m²
Total Cable Power Output (W)

These cables cannot be cut or joined, but more than one cable can be joined to the same thermostat, as long as the total system load/draw is under 3600W/16A (the limit of all ThermoSphere Thermostats) – which equates to a floor heating area of approx. 23m². Larger areas than 23m² with one thermostat are possible, using a ThermoSphere Snubber Unit.

The ThermoSphere Underfloor Heating Membrane & Cable system is easy to install. We recommend laying Tile Backer Board onto the floor area first to provide a thermal insulation layer underneath the membrane. This drastically reduces downward heat loss and speeds up the initial warm up time of the cable, but is not mandatory. Fix the uncoupling membrane to the entire floor area using a suitable adhesive. We recommend using Ardex AF200 or Mapei Ultrabond VS90 Plus for wooden substrates such as floorboards, any flexible cement-based tile adhesive is suitable for concrete, screed, tile backer board substrates.  The self-adhesive membrane does not require any additional fixing adhesive. Then lay the ThermoSphere Heating Cable into the grooves in the matting until you’ve covered the desired area/s that you want to heat. Tiles can then be laid directly over the installation using a flexible tile adhesive.  Levelling compound can also be poured over the membrane to fully encapsulate the installation prior to tiling.

Product Datasheet Installation Guide

Click here to view this product on the manufacturers website.

Additional information

Weight N/A

1m² Membrane Section, 15m² Membrane Roll, 1m² Self-Adhesive Membrane Section, 15m² Self-Adhesive Membrane Roll, 12m Heating Cable (1.15m²), 18m Heating Cable (1.73m²), 25m Heating Cable (2.31m²), 31m Heating Cable (2.88m²), 37m Heating Cable (3.46m²), 42m Heating Cable (3.90m²), 50m Heating Cable (4.62m²), 55m Heating Cable (5.10m²), 61m Heating Cable (5.77m²), 75m Heating Cable (6.92m²), 90m Heating Cable (8.32m²), 100m Heating Cable (9.23m²), 125m Heating Cable (11.54m²), 150m Heating Cable (13.85m²), 175m Heating Cable (16.17m²), 200m Heating Cable (18.46m²)

3 reviews for ThermoSphere Underfloor Heating Membrane / Cable

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