Tag Archives: Wood Fibre Insulation

advantages of wood fibre insulation

The Advantages of Wood Fibre Insulation

The Advantages of Wood Fibre Insulation : it’s all in the trees…

Wood Fibre insulation is a fairly recent addition to the EWI Pro insulation catalogue, so we’re going to talk about the advantages of Wood Fibre insulation. Today’s blog is going to be looking at a few of the many reasons why you would want to insulate your home using the most natural of all insulation materials: Wood Fibre. 

Looking for a more general idea of how external wall insulation can benefit you and your home? Check out our dedicated blog here.

Wood Fibre is Eco Friendly

One of the main advantages of Wood Fibre insulation is how environmentally friendly it is. We source our Wood Fibre insulation from a company called Pavatex, who aim to ensure that their Wood Fibre production process is as eco-friendly as possible. Pavatex are sustainable and environmentally conscious at every turn, creating their Diffutherm insulation boards from waste shavings created by local sawmills that use wood from sustainable forests. Indeed, Pavatex claims not to use ‘any old wood’ for their eco-friendly insulation, a statement that is further emphasised by their prestigious NaturePlus certification.

Wood Fibre offsets an impressive 1.6 tonnes of carbon for every ton of material. From the environmentally conscious timber sourcing and manufacturing process, to the actual purpose of the product (reducing energy consumption in homes), Pavatex has done everything in their power to make their Wood Fibre the most eco-friendly it can possibly be. It’s also 100% recyclable and compostable, so at the end of its long lifespan, the Wood Fibre can be safely disposed of in a non-harmful way.

Wood Fibre is Breathable

Wood Fibre insulation is naturally vapour-permeable. This means that water vapour can travel through the material from the inside to escape on the outside, an essential asset for most buildings in order to prevent damp and structural decay. This is an essential advantage of using Wood Fibre insulation when it comes to older homes. Popularly used with a highly breathable silicone render, or even a traditional lime render, Wood Fibre insulation systems offer a high-performance solution for even the oldest of the UK housing stock.

Wood Fibre has a low thermal conductivity

Going back to basic science, wood is a poor thermal conductor and therefore has excellent insulating capabilities. In terms of U-values, a 200mm thick board of Wood Fibre attached to a 215mm thick solid brick wall can bring the U-value of the wall down to new-build standards – 0.18w/m2k.

Wood Fibre is Fire Safe

Fire safety for cladding materials is understandably a large concern for many homeowners since the Grenfell tragedy, however, Wood Fibre insulation is rated a Class E combustible material. This is because rather than encouraging the flames to grow, the timber typically chars which in turn slows down the spread of fire.

Wood Fibre insulation offers a tight thermal envelope and improved indoor air quality

Another of the many advantages of Wood Fibre insulation is that because external wall insulation is secured to the exterior of a property, the thermal envelope is much more complete than with internal insulation as there are practically no gaps in the insulation. This leaves no room (literally) for thermal bridges, which means that the overall effectiveness of the insulation is much higher. What makes Wood Fibre unique is that it’s incredibly easy to install because it is tongue and grooved, meaning the boards slot together seamlessly so gaps between boards are minimised.

As well as this, because Wood Fibre insulation is such a clean material, it does not release any kind of harmful chemicals and its insulating capabilities prevents harmful emissions from entering the property through the building fabric. Indoor air quality is therefore much higher with Wood Fibre insulation.

Wood Fibre Provides Sun Protection on Lightweight Buildings

Another of the advantages of Wood Fibre insulation goes hand in hand with its abilities to prevent heat loss. Wood Fibre insulation keeps buildings significantly cooler during hot summer days where solar gain is at a maximum. This is because it has the highest thermal mass properties of all insulation materials; this means that Wood Fibre can absorb and retain heat, slowing down the rate at which it enters the interior space. This is ideal for lightweight building structures, such as timber and steel frame, where protection against solar gain is at a minimum.

Not only does this reduce energy bills by minimising the need for air conditioning during the summer months, it dramatically improves the thermal comfort of the building, improving lifestyle and wellbeing.

So there you have it! Wood Fibre is a remarkable insulation material that can offer a building many of its numerous advantages. We’ve previously written a blog all about our Wood Fibre insulation so for more information check that out, or if you’re looking to compare Wood Fibre with our other insulation materials then have a read of our blog post ‘the best type of insulation for EWI?’.

We upload new content every Tuesday and Thursday, so stay tuned for new blog posts all about EWI and render.


Approved Installers Request Form

Your Name*

Your Email*

Your Number*

Your Postcode

Additional Information

I would like to receive news and offers from EWI Store

Why Use Wood Fibre Insulation?

We’ve added Wood Fibre insulation to our product line-up, and we’re really excited about it because Wood Fibre is a completely renewable material with a very low environmental impact. The insulation can bring down the U-values of your external walls enormously, requiring just 120mm to reach a 0.3w/m2k U-value. We know that many customers who consider external wall insulation are very environmentally aware and are eager to choose materials that do not have a negative impact on the environment – we are keen to encourage environmental friendliness wherever possible, and we think that Wood Fibre insulation is the way to go to achieve this.

Because of its recent addition to our systems we thought we’d talk a bit about the benefits of Wood Fibre insulation, including where it comes from and why it’s so great.

Wood Fibre Insulation is Environmentally Friendly 

We source our Wood Fibre insulation boards from a company called Pavatex, who are dedicated to the notion that using secure and healthy forests for production helps to stabilise and manage the environment. Their Diffutherm Wood Fibre insulation boards serve as complete evidence for this, as they boast the achievement of being absolutely sustainable and environmentally friendly. This achievement has not gone unnoticed; Pavatex are certified by the renowned NaturePlus standard – the European quality standard for building materials set up by the WWF, FSC and Greenpeace.

Not only does the nature of their product contribute positively towards the environment, their manufacturing process is environmentally conscious as well. The Pavatex production locations in Cham and Golbey claim to be dedicated to being efficient and environmentally friendly, which has resulted in the Diffutherm Wood Fibre insulation having an overall positive CO2 balance of around 600kg per tonne of product.

When used as part of an external wall insulation system, Diffutherm Wood Fibre insulation helps to reduce the carbon footprint of property owners by lowering the U-values of the external walls of their property, resulting in reduced energy requirements. Wood Fibre boards are also safe to dispose of due to the fact that they are recyclable and compostable once they have reached the end of their lifespan.

The Diffutherm Wood Fibre boards are therefore eco friendly throughout their entire lifespan, and when used as part of our EWI system they will improve indoor air quality, reduce emissions and enhance the thermal performance of the building.

What Type of Property is Best for Wood Fibre Insulation?

Wood Fibre insulation is compatible for use on masonry, steel frame or timber frame structures and even historic or hard to treat buildings; Pavatex have worked with many organisations such as English Heritage, the National Trust, Scottish Heritage and Cambridge University (to name a few), and Wood Fibre also works really well with our new Heritage range of lime products. However, for the purposes of this article we are going to focus on the use of Wood Fibre insulation for timber frame structures.

Wood Fibre insulation is excellent for EWI on timber frame buildings because timber frames need to be able to breathe in order to resist damp and rotting of the timbers. Air circulation is essential, and because of this it can be incredibly difficult to insulate a timber frame property without increasing the risk of damp. This is where Wood Fibre insulation comes in to its own.

When used with a breathable render, water vapour is able to pass through the existing external walls and out through the many layers of the insulation system. We recommend our Silicone or Silicone Silicate renders for use with Wood Fibre insulation, as the breathability of both materials means that they will work well in conjunction with each other. Wood Fibre insulation boards must also be fixed to the substrate with mechanical fixings and our Premium Basecoat adhesive (our strongest and most breathable adhesive), so it will be able to completely support the weight of the Wood Fibre boards and maintain breathability.

Diffutherm Wood Fibre boards are waterproof so they won’t absorb rainwater or moisture, but they’re also vapour permeable at the same time. This essentially means that the Wood Fibre boards will allow water vapour from within the warm building to pass through walls without becoming trapped behind the insulation.

Breathable ‘Nature Plus’ Systems with Wood Fibre

In breathable systems, the insulation materials are arranged in such a way that the layers become increasingly more vapour permeable from the inside to the outside so that moisture can safely escape from within the house. This creates a harmonious climate within the house where moisture and the risk of damp is reduced.

To achieve this, we recommend an environmentally friendly ‘Nature Plus system’. This consists of fitting OSB (which can be taped for air-tightness) behind plasterboard on the interior of the timber stud-work, then laying Nature Plus certified Thermafleece insulation in between the stud-work. You would then install our Nature Plus certified Diffutherm Wood Fibre onto the exterior before rendering as a final step.

How are Wood Fibre Insulation boards made?

Pavatex Wood Fibre insulation is made from local, sustainably managed fir and spruce trees from FSC (Forest Stewardship Council) and PEFC (Programme for the Endorsement of Forest Certification) forests. They are manufactured from untreated softwood in the form of sawmill slabs, chippings and splinters which are a byproduct from the manufacture of timber or sustainably built furniture.

The Pavatex Diffutherm Wood Fibre insulation boards are manufactured in Switzerland under tight environmental regulations against high emissions and pollutants. In order to make Wood Fibre insulation boards, the previously mentioned waste wood is ground together to form a pulp. Water is then added and mixed with the pulp, then heated to activate the lignin that the wood naturally contains and which glues the fibres together. The pulp is then pressed into boards, dried and cut to size. Sheets of varying densities are then laminated together to produce optimal strength and stability as well as moisture control and vapour permeability.

Do Wood Fibre Insulation Boards Pose a Fire Risk?

For many, this is the first question that springs to mind when thinking about externally insulating with Wood Fibre. Pavatex Wood Fibre insulation boards are certified as Class E combustible materials. This is the same as many other insulation materials, however there is a key difference with Wood Fibre boards in that because they are made of timber they characteristically char, which actually slows down the spread of fire. To explain this, Pavatex state that:

‘In a fire a layer of ash forms on the surface of Pavatex Wood Fibre insulation boards. This acts as a safety shield, preventing oxygen from reaching the flames and slowing down the spread of the fire. This means the construction can withstand a fire for 90 minutes. In addition Pavatex Wood Fibre insulation systems do not release dangerous gases in case of fire.’ Check out the video below, which demonstrates this further:

We are really excited to be stocking Wood Fibre insulation! If you have any further questions about installation and technical advice, then comment below or give us a call.

We upload a new blog post every Tuesday and Thursday, so stay tuned for more future content about Wood Fibre insulation and EWI!

Approved Installers Request Form

Your Name*

Your Email*

Your Number*

Your Postcode

Additional Information

I would like to receive news and offers from EWI Store