Underfloor Heating Insulation Board Factsheet

Overview of Heat Mat underfloor heating insulation boards


Insulation Boards

UK manufactured, BBA approved insulation boards

Category: Insulation Boards
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Increase energy-efficiency with Underfloor Heating Insulation Boards

Our thermal insulation board is ideal for insulating your floor and boosting the heating up time and efficiency of your underfloor heating system. The product is suitable for use beneath any of our underfloor heating systems and the boards can pay for themselves, through reduced heating bills, in as little as 3 years when used on un-insulated bases.

Underfloor heating insulation boards minimise downward heat loss. When 10mm boards are used beneath a 200W system the floor will normally heat up in as little as 20 minutes and they add very little build height for a great energy saving measure.

  • Insulation boards increase the efficiency of all Heat Mat systems
  • Available in various thicknesses from 4mm to 70mm to suit your requirements
  • 10mm boards offer a good trade-off between insulation value and build height
  • Structural insulation board guarantees no floor movement
  • Designed to withstand a load of more than 30 tonne/m²
  • Completely waterproof, they will not warp, swell or decay
  • Ideal for creating a wet room
  • Significant soundproofing qualities
  • Made in the UK, BBA approved
Reinforcement tape for joining the boards together is available in a 90m length (covering 36m² of boards).

Board Sizes

Dimensions: All boards are 0.6m wide x 1.2m in length. (4mm, 6mm, 10mm and 20mm boards are kept in stock)

Thickness (mm) Weight (Kg/Board) U Value (W/m²K)
4.0 2.60 3.75
6.0 2.35 3.05
10.0 2.37 2.23
12.5 2.42 1.91
20.0 2.59 1.33
30.0 2.81 0.95
40.0 3.03 0.74
50.0 3.25 0.60
60.0 3.47 0.51
70.0 3.69 0.44

Selecting the correct boards

To start with you will need to decide on the thickness of boards that you should use. The thicker the insulation board the more benefit you will experience, however this is at the cost of build height. In most circumstances a 10mm or 20mm board is ideal, however where build height is highly restricted a 4mm or 6mm board can be used. Once you have decided on the height of the board you will use, you should order enough packs to cover the area of the floor you wish to install them on plus another 5% to allow for off-cuts.

General installation guide

The boards are supplied in simple to transport packs. The packs are light enough for one person to carry and the boards can easily be cut with a knife. The boards should always be laid in a brick-like fashion (as with bricks in a wall) and once the boards are laid Heat Mat recommends taping up the joints between the boards with reinforcement tape to ensure a firm floor base.

Installing onto concrete or tile bases

When installing the boards onto hard floors they are affixed with a standard flexible tile adhesive laid with a notched trowel. The sub-floor should be primed and once the primer has gone off the boards can be secured down with the tile adhesive in a bed a couple of mm thick.

Installing onto floorboards or wooden bases (not 6mm boards)

10mm and thicker boards are suitable for securing wooden and chipboard floor bases and in these circumstances they are screwed down with at least 21 screws per board. Screws with 35mm washers should then be used to secure the boards at 300mm centres.

Waterproofing in wet rooms

If the boards are being used in a wet room to provide the tanking system all joins should be waterproofed with a silicon sealant. The simplest way to do this is to run a bead of sealant along the edge of the board before it is laid and then push it up to the abutting boards to complete the seal. All joints must still be taped with reinforcement tape afterward.

Coated vs uncoated boards

Heat Mat Underfloor Heating Insulation Boards are concrete faced which provides many benefits over uncoated non-reinforced boards. One of the main benefits of coated boards is they resist point loads so are not crushed during installation. They also prevent broken tiles and cracked grout if significant weight is placed on the finished floor, which can be a problem with uncoated boards. Coated boards provide Class O fire protection (uncoated boards offer no protection) and the concrete layer also helps the heat from the heating cables to spread providing an evenly heated floor.

Insulation Boards For Electric Under Floor Heating

Underfloor Heating Insulation Boards Technical Specification

Compressive strength: 300kPa
Thermal conductivity to BS874: 0.027W/mK
Thermal conductivity to BS EN 13164 - 5 year test: 0.031W/mK
Water absorption: 0.2% by volume
Density: 36Kg/m³
Flexural strength (transverse): 600kPa
Flexural strength (Longitudinal): 700kPa
Temperature range suitability: -50°C - +75°C
Fire resistance to BS 476 part 6, 7 surface spread of flame: Class O


Underfloor heating insulation boards


Product Code Description TSI Code GTIN No.
TTB-004-4PCK 4mm Thermal insulation board - 2.88sqm 403084393 5060424144082
TTB-004-5PCK 4mm Thermal insulation board - 3.60sqm 403084416 5060424144099
TTB-006-5PCK 6mm Thermal insulation board - 3.60sqm 402060952 5060424143771
TTB-006-6PCK 6mm Thermal insulation board - 4.32sqm 402061061 5060424143788
TTB-006-7PCK 6mm Thermal insulation board - 5.04sqm 402061074 5060424143795
TTB-006-8PCK 6mm Thermal insulation board - 5.76sqm 402061100 5060424143801
TTB-010-4PCK 10mm Thermal insulation board - 2.88sqm 398699987 5060424142972
TTB-010-5PCK 10mm Thermal insulation board - 3.60sqm 398699990 5060424142989
TTB-010-6PCK 10mm Thermal insulation board - 4.32sqm 398700012 5060424142996
TTB-010-7PCK 10mm Thermal insulation board - 5.04sqm 398700025 5060424143009
TTB-020-0004 20mm Thermal insulation board - 3.60sqm 389521268 5060424143016
TTB-111-0090 90m roll TTB reinforcement tape 389521307 5060424143030
TTB-111-1000 25mm Screws and washers for TTB x 50 screws 394573858 5060424143047