
Because of its ability to rapidly absorb and release water vapour, THERMAFLEECE wool insulation can help to keep buildings cool in summer and warm in winter.
NATURALLY BREATHABLE - being hygroscopic, it can absorb and desorb water vapour without compromising its thermal efficiency. It is therefore ideal for use in roofs and timber framed walls designed to avoid a damaging build-up of moisture by allowing water vapour to migrate through the structure.
CONDENSATION CONTROL - Wool generates heat when it absorbs moisture from the air. That energy is known as the heat of sorption and accounts for the warmth felt by wearers of woollen clothes in winter conditions. When the air is saturated with water vapour, wool absorbs some 40% of its dry weight in moisture, producing 960 kilojoules of heat energy for every kilogram of dry wool. This warmth is not noticeable inside the building but it acts to prevent condensation in construction cavities by maintaining the temperature above the dew-point in damp conditions.
ENERGY EFFICIENT - it uses only 14% of the embodied energy that is used to manufacture glass fibre insulation, therefore paying back its manufacturing energy cost seven times faster than glass fibre.
HARMLESS - it can be installed without gloves or protective clothing. It is not irritating to the skin, eyes or respiratory tract and causes no discomfort to site workers during installation. Any fibres which happen to reach the living space will present no hazard to health. The necessary insect proofing and fire resistance rating is achieved by the inclusion of naturally derived additives.
EXTREMELY DURABLE - the fibre adapts to the shape of rafters, joists and studs to provide a permanently tight fit. Properly installed, it will retain its low density and thermal performance - with a life expectancy similar to that of the construction in which it is installed.
At the end of its useful life, it can be RECYCLED for other environmentally friendly applications.
It contains no permethrin, pyrethroids, pesticides or formaldehydes and so is completely safe to use and live with.
The low thermal conductivity of THERMAFLEECE (0.039W/m.K) compares favourably with that of other fibrous insulants.
The product contains a necessary lofting agent and so it maintains fibre stability.
It has a higher fire resistance than cellulose and cellular plastic insulants; it does not burn but rather melts away from an ignition source and extinguishes itself. THERMAFLEECE is treated with a natural fire-proofing agent to improve its intrinsic fire resistance and comply with BS 5803-4 (Spread of Fire) achieving results of zero for ignitability, spread of flame and heat evolved.
It is protected against attack by moths and beetles using a borax treatment. Borax is a natural mineral salt that is used in a wide variety of applications. The use of borax to treat wool is extremely safe and poses no risk to people or the environment. Our wool is treated with borax at the wool cleaning stage to ensure a consistent treatment that penetrates deep into the wool fibre.
It has good acoustic properties - see Documentation, which means that it can now be specified as part of your noise control scheme.
The above are points are made with reliance of Second Nature's own published material and the BBA certificate - all of which are in the documentation section.
Why should I insulate?
According to the Energy Saving Trust, an average sized property installed with 270mm of loft insulation can expect:
1. Saving on heating bills of up to £180 to £220 pounds every year
2. Reduced CO2 emission by up to 400kg
3. Greater comfort in both winter and summer
Why use sheep's wool insulation?
See the benefits section of this website.
Why should I be concerned about indoor air pollution?
Indoor air pollutants can cause health effects ranging from respiratory irritation to cancer. They have been linked to sick building syndrome and can have a significant impact on quality of life.
How can I minimise the level of indoor air pollution?
Reducing sources of pollutants and ensuring a supply of fresh air are critical. The use of pollutant reducing building materials such as Thermafleece will have an impact on indoor pollutant levels.
How does Thermafleece reduce formaldehyde levels?
The protein building blocks in the wool fibres react in a complex and permanent way with formaldehyde molecules. The reaction is very rapid and cannot be reversed even at high temperatures. Under typical conditions, tests have shown that the wool in Thermafleece will absorb formaldehyde for at least 30 years.
Can I just use the wool from my farm?
No, raw wool must be cleaned using a scouring process and treated to protect against insect attack and improve fire resistance before it can be used for insulation. The clean wool is then blended with a polymer binder to help it keep its structure. The blend is then formed into light weight non-woven insulation using a state of the art manufacturing process.
Why is it so much more expensive than buying raw wool?
Wool purchasing, processing and manufacturing costs are substantially higher than the raw wool itself. The market structure for wool purchasing is set by the British Wool Marketing Board and we are bound by their rules. Like many manufacturing processes, the price of the unprocessed raw material is only a fraction of the processing, manufacturing and marketing costs required to create a finished product.
Why don’t you process it in Wales?
We have conducted extensive research and concluded it is better for the environment if we utilise existing capacity and manufacture insulation in close proximity to the main wool collection and processing sites in the North of England (where all the wool goes to be scoured) BUT using Welsh wool. We then transport finished insulation to our Brecon Warehouse in large loads to enable flexible local distribution and to minimise environmental impact of transport.
Where does your wool come from?
All of our wool is purchased through the British Wool Marketing Board, at least 75% of which originates from the Welsh collection stations in Brecon, Porthmadog and Newtown. By sourcing Welsh wool in this way, we are helping generate a market for a local material and are able to put money back into the local, rural economy. We feel this is sustainability in action!
Welsh wool insulation has a much lower environmental impact than ‘cheaper’ sheep’s wool products that contain wool imported from as far afield as China and New Zealand which often have a worse environmental impact than some of the conventional materials they are designed to replace.
By using Ty-Mawr Thermafleece, you can be sure you are buying genuine Welsh sheep’s wool with the minimum number of road miles used to transport the insulation to you!
How do I install Ty-Mawr Thermafleece?
Ty-Mawr Thermafleece is harmless and can be installed without gloves or protective clothing, although we do recommend that you wear a dust mask in an enclosed space like a loft. It is not irritating to the skin, eyes or respiratory tract and causes no discomfort to site workers during installation. Any fibres which happen to reach the living space will present no hazard to health. The health concerns around glass fibre insulation do not apply to this product.
How easy is Thermafleece to install?
Thermafleece is very easy to install and does not require skilled labour.
• Thermafleece is harmless and can be installed without gloves or protective clothing. It is not irritating to the skin, eyes or respiratory tract and causes no discomfort to site workers during installation. Any fibres that reach the living space will not be hazardous to the health of occupants. We do however recommend that you wear a mask in an enclosed dusty area, such as a loft.
• Even though Thermafleece is a tough and durable product it can be cut to size, or alternatively 'torn' apart using your hands.
How can I cut sheep's wool insulation?
For accurate cutting, tightly compress or clamp the insulation between two pieces of solid 15mm board. Overhang the fleece where you want to cut keeping the two board edges aligned. Saw cut the edge using a sharp, scalloped edged knife and keep the blade firm and square against both board edges throughout. Trim any fine remaining fibres with large scissors or shears. Ty-Mawr Thermafleece can also be cut using a straight edge and a Stanley knife, or simply torn apart.
Does Thermafleece meet Building Regulations?
Yes, Thermafleece has British Board of Agrément (BBA) for three applications, meaning that it totally complies with Building Regulations, in between joists in ventilated and unventilated lofts; under pitched roofs and between rafters for tiled or slated pitched roofs, as well as timber frame wall applications between studding with a weather resistant cladding, and a ventilated and drained cavity.
What depth of sheepswool insulation is required to achieve insulation government recommendations for loft insulation?
Sheepswool has marginally better thermal conductivity values to conventional mineral fibre insulation (0.039 W/mK). Therefore the government recommendation of 10 inches or 250mm is applicable.
Please use our quantity calculator on this website which we have written specifically to help you work out the number of batts or rolls you require!
There are now many natural fibre products on the market – how do I know which to choose?
You should satisfy yourself that :
1) it meets your technical performance requirements - the easiest way is to check that the product has appropriate certification. Ours is still the only fully British sheep's wool insulation product with full BBA certification, this gives you the peace of mind to know that the product will perform in the application you use it in exactly the way we say it will for the life of the building!
2) it meets your environmental credentials - see Where does your wool come from? above - this is not easy but anyone using these products generally cares about the environment, although there maybe 'cheaper' natural products available, you should try to look at the whole picture e.g. where the raw material comes from, where it is manufactured, what road miles are involved in its production, what is the embodied energy of the production process - in our experience, you do pay for what you get!
3) value for money - it is not as easy as just comparing price per square metre of these products any more, you also need to look at the technical characteristics and importantly the service life of the product. Sheep's wool insulation has a service life of of the building in which it is installed which makes the initial investment look healthier!
From the BBA Certificate "The product is stable, rot-proof and durable and will remain effective as an insulant for the life of the building in which it is installed."
It should also be noted that because it does not loose it's thermal value when/if it gets wet/damp like conventional insulation, it is actaully doing a better job, we find that this is an especially important consideration in older buildings!
Can I get a grant?
It is possible to get a grant to insulate your home – the best website in Wales to check is the Home Energy Efficiency Scheme http://www.heeswales.co.uk/do-i-qualify.htm,or call 0800 316 2815.There is also a lot of useful information on the Energy Saving Trust website as well as other sources of grants but don’t be put off if the installer refuses to use natural insulation, they will be tied into a scheme, call us and we will try to help you find a local installer who will use it although most clients either do it themselves or get their usual builder to do it as it is so safe and easy!
Can I 'top-up' my existing insulation?
Yes, we would advise that you lay the batts crosswise over the mineral fibre, this will cover up the glass fibres and avoids having to remove it and disturbing the fibres.
Is it a better insulator than conventional insulation?
Thermafleece provides better insulation performance than many conventional insulation materials such as fibreglass. Thermafleece can provide more than 10% performance improvement compared to conventional fibreglass insulation. What’s more, because wool fibres bind free moisture, the insulating performance of Thermafleece is not significantly affected by fluctuations in levels of humidity compared to conventional insulation materials.
How much more expensive is it than conventional insulation?
The price of other insulation varies greatly so it is difficult to make an exact comparison. However, the price difference has narrowed as the energy costs in producing conventional insulation have increased. Thermafleece, along with most natural insulations, tends to be more highly priced than the mainstream, but do bring significant attributes to your home.
What is embodied energy?
Embodied energy usually refers to the embodied energy of manufacture which is the amount of energy used to produce a product. Because wool processing and wool insulation manufacture does not need the very high temperatures required for mineral or glass wool manufacture, Thermafleece has a lower embodied energy of manufacture compared to these types of insulation.
Are any of the chemicals used to dip sheep still present in sheep’s wool insulation?
No. The raw wool fleeces are thoroughly scoured to clean them and remove any chemical residues from the raw wool.
Is it affected by moisture?
The insulating performance of Thermafleece is not significantly affected by fluctuations in humidity levels. Wool fibres can bind up to 40% of their weight in moisture before feeling wet. This effect, reduces the likelihood of free moisture conducting heat within the insulation which can reduce insulation performance. The ability of the wool fibre to absorb and release moisture also helps promote a more stable level of humidity within the building envelope helping contribute to a healthier indoor environment.
Is sheepswool insect and rodent proof, and is it fire proof?
Sheepswool insulation is treated with natural mineral based agents to prevent infestation, and meets class O fire regulations.
What is the difference between Ty-Mawr Thermafleece and the PB20 Rolls?

Can I use Ty-Mawr Thermafleece to insulate my walls?
Yes, it can be combined with wood wool or woodfibre boards to upgrade the insulation value of solid wall buildings without compromising the vapour permeability. We provide full support for all our products and are happy to look at u-value calculations, condensation risk analysis etc for your specific wall build up - email us on technical@lime.org.uk
Are there any grants available for solid wall insulation?
No, as far as we know there are no nationally available energy efficiency grants for solid wall insulation. There may be some local schemes running particularly in Neighbourhood Renewal Areas or other regeneration projects. If you are in one of these, or similar areas it may be worth checking with your local council as insulation may be included in a renovation or home improvement grant.
Can I insulate around flu pipes with Thermafleece?
Working on a double skin flu, building regulations states there must be a 50mm gap from the flu and insulation.
Can I insulate my water tank & pipes?
Yes.
Will the wool delaminate or slump?
Due to the cross-fibre technology used in its manufacturing process the wool will not slump over its life and will remain stable. As PB20 is compressed for transportation it should be allowed to regain its form before installation.
How do I store it?
Store under cover and clear of the ground. It should also be protected from prolonged exposure to sunlight when unpacked and avoid wetting for extended periods.
How long will Thermafleece last?
Thermafleece will last the lifetime of the building in which it is installed.
Do mice like sheep's wool insulation?
It will not 'attract' them any more than any other insulation but you should take appropriate precautions, close up gaps etc to deter them.
Can I insulate my timber floor with wool?
Timber floors can be insulated by lifting the floorboards and laying the wool insulation between the joists - see applications.
Do you deliver ?
Yes, we choose the most cost effective way of getting product to you. It varies depending on the quantity and type of product ordered, we deliver with our own vehicles or with National pallet carriers. If you use the quantity calculator on this website, it will not only calculate the amount of material you require but also the delivery cost for you, we are also happy to do this over the telephone, just call 01874 611350 or email us at tymawr@lime.org.uk