Ecological Building Systems

You are shopping in

The “GB” region can deliver orders to England, Scotland and Wales. For Northern Ireland deliveries, please choose the “Ireland” region.

Your region is: Great Britain Not right?
An image of a product
An image of a product
An image of a product
An image of a product An image of a product
An image of a product
An image of a product

Gutex Thermoflex

Choose width and thickness (8 options)

Product calculator

I need m2 of Gutex Thermoflex
  • Product Overview
  • Technical Details
  • Downloads
  • Installation guide

Product Overview

Main purpose

High performance breathable thermal Insulation to protect buildings from cold in winter and overheating in summer.

Use it on

Timber frame walls, roofs and floors and as loft insulation installed between ceiling joists in a loft space.


Gutex Thermoflex is a high performance easy-to-install flexible wood fibre insulation made from recycled wood chips. Thermoflex is supplied in 1350mm long mats (batts) and provides excellent thermal insulation in winter and helps to significantly reduce the risk of overheating in Summer. The product is also highly breathable so can assist in regulating humidity and controlling moisture in the building all year round.

Where to use it

Gutex Thermoflex mats can be used in between rafters, joists and studs in walls, roofs and suspended timber floors. It can also be used as loft insulation installed between ceiling joists in a loft space. Thermoflex is suitable for internal or external timber frame stud walls, pitched roofs and flat roofs.

What it does

Gutex Thermoflex provides excellent thermal performance in the winter months and reduces the potential for summer overheating.

It is highly breathable (moisture vapour diffusion open), which means that it can assist in regulating internal humidity and help prevent interstitial condensation and mould growth within the fabric of the building. Control of condensation and eradication of mould make an excellent contribution to the improvement in indoor air quality.

Thermoflex insulation mats can be used in conjunction with breathable external structural boards (for example Elka Strong Board) and with Pro Clima Intello Plus. This provides excellent breathability in winter and allows for moisture driven back into the building by summer sun, to dry harmlessly.

Why we love it

Gutex Thermoflex is ideal for insulating new buildings or thermally upgrading existing buildings. It is easy to cut and easy to install by squeezing it in between timbers. Friction and the spring of Thermoflex keep the insulation securely in place, making it ideal for DIY or professional installation. It is a natural product that is safe to handle, does not irritate skin. 

Thermoflex is made from recycled wood chips that were produced as waste from locally manufactured products for the timber frame industry. The wood chips were originally trees grown in sustainably managed forests. As the carbon emitted during manufacture is less than the carbon absorbed by the trees and stored in the wood, Thermoflex actively contributes towards reducing global CO2.


  • Easy to install
  • Superb thermal performance
  • Excellent winter thermal performance and summer overheating reduction
  • Breathable
  • Excellent acoustics
  • Sustainable


  • Flexible and lightweight, it fits snugly between wall studs and rafters with no gaps. Makes for an easy DIY installation.  
  • Top performing thermal insulation creates a cosy, comfortable indoor environment, helping reduce heating bills and keep you cool in summer.
  • Breathable natural insulation allows moisture vapour to move through the insulation preventing a build-up of damaging condensation. This prevents mould forming and ensures great indoor air quality.
  • Reduces airborne noise between rooms and floors due to its excellent acoustic dampening properties
  • Made from recycled wood chips from sustainably managed forests. More carbon is stored in the wood fibre than emitted by manufacture.


There are currently no questions and answers published for this product

Ask A Question

Technical Details

Key Technical Data

Technical Datasheet

  • Download

Material Safety Datasheet (MSDS)

  • Download


  • Download

Environmental Product Declaration (EPD)

  • Download

Declaration of Performance (DOP)

  • Download

System Brochure

  • Download
  • Download
  • Download

Brand/Manufacturer Brochure

  • Download
  • Download
  • Download

Installation Guide

How to Install

Gutex Thermoflex should be cut so it is 10mm larger than the space in which it will be installed. The insulation should then be placed in between the timbers. 

Being slightly oversized, it will be compressed and grip the timber to stay in place without slumping or movement. For loft application, the first layer should be fitted in between ceiling joists and then a second layer should be laid over the top of the timbers at right angles to the first layer.  

Thermoflex that has been cut 10mm too large being fitted between two roof joists.
Cut Thermoflex 10mm larger than the actual space for a snug fit
Gutex Thermoflex neatly compressed in-between two joists.
Gutex Thermoflex neatly compressed in-between two joists
A man squeezing a Thermoflex mat to demonstrate its flexibility.
Thermoflex is designed to be flexible but retain its shape and not slump

Hints and Tips

Combine Gutex Thermoflex with Elka Strongboard (externally) and Pro Clima Intello Plus internally, for a fully breathable building element.

Recently viewed products

This website uses cookies to ensure you get the best experience on our website. 

View our cookie policy here.