Thermafleece CosyWool Roll is non-hazardous and can be handled without protective clothing, although we recommend you wear PPE in spaces such as lofts.
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Thermafleece UltraWool is our denser insulation slab that is designed for use where space is limited. The insulation is designed to friction fit comfortably between studs and rafters.
Download FactsheetBefore ordering your insulation, measure your loft to calculate the total area you need to insulation. This will help you determine the quantity of insulation required and ensure you choose the correct product dimensions for your project.
Use the calculator below to estimate how much CosyWool insulation you will need for your project. It’s a simple guide to help you calculate the quantity required before you order.
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Use the calculator below to estimate how much UltraWool insulation you will need for your project. It’s a simple guide to help you calculate the quantity required before you order.
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Airtightness, vapour control and breathability play a critical role in the operational performance of buildings. Understanding how they work together enables us to control air leakage, maximise energy efficiency, optimise indoor air quality and ensures durability of the building fabric.
Learn more about Thermafleece air-tightness, breathability and vapour control.
Thermafleece CosyWool is compress-packed to minimise packaging waste and reduce the environmental impact of transportation from the factory.
Because it is compress packed, the insulation requires time to “loft” or return to its original thickness once opened.
Find out how long it will take for CosyWool to return to its original thickness.
“Mineral fibre” is a general term for common insulation materials like fibreglass and rockwool. While Thermafleece and mineral fibre can be used interchangeably in many building situations, Thermafleece offers several distinct advantages.
Learn about the differences between Thermafleece and mineral fibre insulation.
In an acoustic system, Thermafleece acts as the absorbent in-fill within voids, breaking up sound waves and reducing the amount of sound reverberation or echo in the void.
Find out about the sound-absorbing properties of Thermafleece.
Making a like-for-like comparison between PIR boards and Thermafleece is challenging because they are completely different products. Choosing the right one depends entirely on what you want your insulation to achieve.
Breathability is a property that prevents the accumulation of harmful water—liquid water or persistently high humidity—within a building’s structure. While it does not replace primary systems like ventilation or weatherproofing, it is an important factor in maintaining stable, harmless moisture levels within the building fabric.
Thermafleece is a British-made, sustainable insulation rich in British sheep’s wool. It is a natural fibre insulation designed to be highly breathable and provide long-term thermal and acoustic performance.
Thermafleece uses wool from hardy hill and mountain sheep in England, Scotland, and Wales. The sheep run free on fells and mountains and are shorn annually in the spring.
We treat Thermafleece with a borax-based fire retardant because of this our wool is not susceptible to clothes moths or carpet beetle damage.
To find out more about the borax treatment process read our ‘Insects and Durability‘ information sheet.
The polyester binder ensures the insulation maintains its shape and structural stability, preventing it from slumping over time.
It allows for a lower-density product with high thermal performance and enables the insulation to be compressed for more efficient shipping and reduced packaging.
Thermafleece is designed to be compatible with the natural environment. Our use of borax (sodium borate) provides essential protection against wool-eating insects while remaining safe for protected species like bats.
See how Thermafleece has been designed to interact safely with the natural environment.
The amount of insulation you need depends on where you’re installing it.
Check our application guidance for more details, or use our estimator tool with your project’s dimensions to calculate exactly how much to order.
Downloads of our events and presentations can be found here.
Want to learn more about natural fibre insulation? Discover the benefits that sheep’s wool and other natural fibres bring to the built environment by visiting the ASBP Natural Fibre Insulation Group (NFIG).
Navigating insulation options doesn’t have to be confusing. Our team is here to simplify the process, providing everything you need to know, from answers to common questions to expert guidance on complex build-ups.
Thermafleece has been used in a vast range of projects across the UK for over 25 years. Explore our case studies to see how properties of all shapes and sizes from historic restorations to modern eco-homes have benefited from our British wool insulation.
Insulating your loft with Thermafleece sheeps wool insulation is a great DIY project because it’s easy and safe to handle. Read our simple, step-by-step guide to help you get the job done correctly and safely.
Our experts can provide U-Value calculations and condensation risk analysis. For calculations, please fill in our online request form with details of your building elements and we’ll get back to you with your calculation report.
Download our application guides for roofs, walls, and floors below. These resources are designed to make using and specifying Thermafleece straightforward and understandable, helping you create a healthy, breathable building.
We’ve compiled a list of the most common inquiries to help you get the information you need quickly. If you can’t find what you’re looking for, please get in touch.
Yes. It is non-itchy, safe to handle, and can be installed by homeowners. UltraWool friction-fits between rafters and studs, while CosyWool is ideal for laying between and over joists in lofts and floors. CosyWool also friction fits but this is not so important for horizontal applications.
Download our product factsheets here
While both materials are great for sound absorption, Thermafleece offers distinct advantages over mineral fibre like fibreglass and rockwool. Unlike mineral fibre, Thermafleece actively buffers humidity to reduce the risk of condensation, naturally absorbs indoor pollutants like formaldehyde, and carries a lower carbon footprint.
While mineral fibre is cheaper upfront, the long-term energy savings of Thermafleece make the lifetime cost difference negligible.
Thermafleece is suitable for most standard building applications, though mineral fibre remains necessary where non-combustible fire ratings are necessary.
Truly breathable insulation must be vapour-open and also be able to buffer moisture. Thermafleece absorbs and releases moisture to help manage humidity levels and maintain the structural health of the building fabric.
Read more about breathability here
It is important to take the time to calculate how much insulation you need to ensure the best fit and avoid over or under-ordering. Planning the installation is an important part of the job, and correctly installed insulation will significantly improve thermal performance.
Tools Required: Sharp Scalloped Edge Knife or Insulation Saw.
While it can be torn by hand, the recommended “Roll and Cut Method” provides a neater edge. This involves rolling the insulation tightly and cutting through the roll with a sharp scalloped edge knife or insulation saw.
FOR AN ACCURATE LENGTH: If you have a slab or a roll and want an accurate length, take the insulation and roll it as tightly as possible along the width. Measure where you need to cut to give you the length you require. Taking the insulation saw / knife easily cut through. This provides a nice, neat edge and is an alternative to tearing by hand.
TO CUT THE WIDTH OF THE ROLL: Tightly roll a length of insulation, typically up to 2.5m. Keep the insulation rolled and do not unwind. Measure the required width that you need then using the knife or insulation saw begin to cut through the whole roll.
Both CosyWool and UltraWool contain 75% British wool, 15% recycled polyester loft agent, and 10% polyester binder. The recycled polyester helps create a ‘bouncier insulation’ that enables us to compress pack and the binder provides strength and durability. The polyester does not affect the breathability of the insulation.
Thermafleece is an excellent insulation product that makes great use of British wool. It offers excellent thermal performance while allowing the building to breathe, helping us meet building regulations. Installation was quick, simple and safe, with no fuss.
We are great fans of Thermafleece CosyWool sheep’s wool insulation & have used it for approximately 20yrs. It is so much more than a quilt insulation. It’s ability to control vapour within a structure is outstanding. Plus it’s so nice to handle!
The thermafleece cosywool sheep’s wool insulation was amazing to work with and very easy to lay. We noticed the difference immediately and are super pleased with its performance so far. Service from ordering to delivery was excellent.
Meets all insulation and regulation requirements beautifully. So much better than other man made alternatives. So much better to install. Far more healthy from many angles – especially installation – no irritating particles.
My loft was insulated with fibreglass, which required me to wear a face mask when entering the loft, and I needed to replace it.
As a sheep farmer, I looked into using sheep’s wool. I thought that this was the right thing to do environmentally, “walk the
UltraWool is an excellent sustainable product. Being sourced and manufactured in the UK helped reduce our project’s carbon footprint, and it was safe and easy to install without the need for special protective equipment.
Lovely to be using a natural product. Not sure we had the right tools to cut it, but managed with scissors and persistence! Used to insulate the summer house in the garden – feels very cosy in there now.
Insulating with UltraWool signigicantly reduces the amount of energy lost from the building envelope, reducing energy consumption and carbon dioxide released to the atmosphere
Breathable natural fibres contribute to a more stable humidity and moisture lev
Felt the Difference all most right away.
Beyond its fantastic and self-evident insulative properties, the most remarkable thing for us was how pleasant Thermfleece insulation was to use. It turned the job of insulating from a messy, uncomfortable and unpleasant task to one we genuinely looked forward to.
Choosing a natural insulation product was a key priority for us, and Thermafleece CosyWool proved to be an excellent choice. We liked that it’s British made and supports local farmers, while also allowing our older property to breathe naturally.
CosyWool is a versatile insulation rich in British sheep’s wool and the ideal choice for all round performance and value for money. The wool rich blend ensured the full benefit of sheep’s wool with enhanced performance, durability and sustainability.
The moisture wicking properties together with the air purifying quality of CosyWool are the real reason I always choose it, allowing the building to breathe and removing toxins from the air make it the obvious choice.
fantastic to work with
This stuff is so much easier to install than rockwool, fibreglass or celotex.
Great product. Very pleasant and easy to use.
Simply excellent! Gone are the itches of fibre glass loft insulation instead a natural product of sheep’s wool, wrapped around your house for warmth. Must try a wool jumper again myself!
Great price and product
Thermafleece insulation has transformed our house. It was easy to install in our attic – we did it ourselves – it was all done in a day. Best thing ever.
No irritation from the sheep’s wool, made the room warmer straight away.
Worth it just for the abilty to breathe while using it and not getting itchy. Rips apart easily with hands or decent scissort. Excellent Product.
So easy to work with and has made a real difference to the warmth in the room below. Will be looking to replace all our loft insulation with this
Excellent quality insulation.
Effective and easy to use, fast and great service.
I’ve used the wool insulation for my campervan conversion very happy with the with the product
Great to handle and very easy to install.
Exactly as described, perfect for the job I was doing.
Excellent product, service, and delivery
Good price for item that we have used before. Straight forward order and delivery.
Really helpful with getting the right amount and overall great service, super range of products. about to buy again!
Take a look at the projects showing the versatility of our products.
We understand that choosing the right insulation for your project can be daunting. That’s why our team is on hand. We offer impartial and truthful advice as well as providing general and technical help. So feel free to submit an enquiry via our contact page.
Alternatively call us on 01768 486 285
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