Best Seller

Steico Therm Internal T&G

Steico Therm (T&G) Internal - Wood Fibre Insulation Board

Write a review



Test Category

No Downloadable

No Specification

Play Videos

Product Tags

Use spaces to separate tags. Use single quotes (') for phrases.

full view icon

Steico Therm Rigid insulation board T&G edged is made from natural wood fibres. The tongue and groove edge adds the following advantages over the square edge board.

  1. Easier to fix to studs and rafters with an OSB backer board
  2. Quicker and easier to install
  3. Improves airtightness 
  4. Improved joint strength
  5. Less likely to leave gaps when installing

Steico Therm Rigid insulation board T&G edged is normally used for internal renovations where the structure is built on studs (timber frame or a stud sub frame).  Using the T&G profile for stud applications helps minimise potential cracking of the plaster coat the T&G profile locks the boards together, effectively supporting the joints but the use of an OSB backer board is recommended.

Like the square edge board Steico Therm T&G is suitable for wall and roof applications it can also be used as sub screed insulation (please ask us for technical guidance for sub screed use)

Easy and fast fixing wood fibre board with superior insulating properties in both summer and winter. High compressive strength, water vapour open (helps regulate the indoor climate of a building) & fire resistant.

The board has a light side (machine sanded in the factory) and a darker unsanded side, the lighter side is the plaster carrying face.

FSC® accredited, ecologically friendly, recyclable.

1200mm  x 380mm, each board covers 0.434m2

Price is per board

full view icon

Steico Therm is a rigid thermal insulation board made from sustainably sourced natural wood fibres for application in roof, wall and floor systems.

Steico Therm tongue and grove edged boards are available in the following sizes:

Thickness mm

Dimensions mm

Weight per sheet kgs

Maximum sheets per   Pallet


380 x 1200




380 x 1200



Steico Therm Internal is a T&G edged wood fibre board that has many uses in eco friendly homes. Predominantly sold by Ecomerchant for internal wall insulation, it is used to fit on to rafters, joists and studs with an OSB backer board.  

This insulation material is water vapour open, which means that water moisture can pass through it without hinderance. If you have a house built with lime mortar, this can be a critical factor in deciding which insulating materials you need to use to insulate your house. With most houses built before 1920, builders relied on the heat within the house to force any excess moisture to the outside. Lime is breathable so the moisture would breath out through the walls. If you apply something like polystyrene to the inside wall of this type of house, then moisture could become trapped and start causing the likes of mold and mildew.  By correctly setting this eco friendly board to a wall built with lime mortar and plastered with Lime plaster, the structure can continue to breath as it should and you will get a upgrade to the thermal performance of your house.


  • - Steico Therm has high compression strength
  • - Steico Therm has high heat protection during summer months (absorbs heat from the sun and give it off when it gets cooler)
  • - Steico Therm has excellent insulation qualities
  • - Steico Therm is water vapour open
  • - Steico Therm helps to regulate the indoor climate, due to the long phase shift so helps with summer heat protection as well as winter heating.
  • - Steico Therm is an eco friendly insualtion board
  • - Steico Therm rigid insulation board is recyclable
  • - Steico Therm is an accredited heat insulation material


  • - Wood fibre insulation board produced in accordance with EN 13171 with on-going quality supervision
  • - The wood comes solely from sustainably cultivated forest

Produced and supervised according to EN 13171

Board designation

WF – EN 13171 – T3 – CS(10 \ Y)40 –TR2,5 – AF 100

Edge profile

Tounge and groove

Fire class according to EN 13501-1


Declared thermal conductivity λD [ W / ( m * K )]


Declared thermal resistance RD [( m2 * K ) / W]

0.5 / 1.0 / 1.5 /2.0 / 2.5 / 3.0 / 3.5 / 4.0

Density [kg / m3]


Water vapour diffusion resistance factor μ


Sd value [m]

0.1 / 0.2 / 0.3 / 0.4 / 0.5 / 0.6 / 0.7 / 0.8

Specific heat capacity c [J / (kg * K)]


Minimum compression strength at10 % deformation σ10 [N / mm2]


Minimum compression strength [kPa]


Tensile strength perpendicular to face ^ [kPa]

≥ 2.5

Declared level of airflow resistance [( kPa*s ) / m2]

≥ 100

Raw material

wood fibre, bond between layers

Waste code (EAK)

030105 / 170201

Not sure if this is the right product for you?  Want to talk about it?  Please contact our team on 01793 847 444 or email your enquiry to

Write Your Own Review

You're reviewing: Steico Therm (T&G) Internal - Wood Fibre Insulation Board

How do you rate this product? *

  1 star 2 stars 3 stars 4 stars 5 stars

Availability: In stock

  • Buy 80 for £3.66 each and save 11%

* Required Fields


You may also be interested in the following product(s)