Moths do not like Sisalwool.
We use a long-lasting, biodegradable insect deterrent treatment to moth proof our wool. The treatment works as an insect resistance agent by making the wool
protein unpalatable to the wool moth larvae.

No, Sisalwool won’t stop mice or other rodents if they're in the building but it’s no more problematic than any other insulation.

Sisalwool is a blend of sisal and wool. Sisal is a sustainable fibre crop, used to make a variety of items across the globe, including dart boards, ship ropes and coffee sacks. The latter of which is used in our insulation. The wool is sourced from waste and off-cuts from the clothing and carpet making industries.
Our loftroll is made from the same sisal fibre but uses cotton from denim offcuts instead of wool, which not only makes it flexible and easy to lay, but also makes it a vegan product and gives it a vibrant blue hue.

In a direct comparison with conventional insulation materials, Sisalwool has a similar thermal performance to stone wool type products and a better thermal performance than glass fibre. It outperforms fibreglass and foam products, such as Polyurethane and EPS, in terms of breathability. Sisalwool is also non-itchy, free from harmful chemicals and risky irritants. This means protective gear like gloves and masks are totally optional. Not to mention the long-term benefits of a healthier breathing environment.

Absolutely! We use low carbon materials and processes from start to finish. We prioritise using off-cuts from the carpet and clothing industry for wool, and used coffee sacks from roasters across the UK for our sisal.

Sisalwool Loftroll comes in large, flexible rolls that are ideal for quickly insulating loft floors between joists. 

Sisalwool 50 & 100 slabs are pre-cut batts designed for a snug fit in walls, roofs, and floors – perfect where a secure, friction-fit is needed. Both offer the same thermal and breathable performance.

No, the insulation is odourless.

Sisalwool currently comes in depths of 50mm and 100mm. A 50mm and 100mm can be used together and squeezed down to 140mm.

Sisalwool has been tested to Euroclass E for reaction to fire, meaning it self-extinguishes when exposed to a small flame and does not melt, drip or emit toxic fumes. This rating makes it suitable for use on non-boundary walls in homes up to 11 metres in England and up to 18 metres in Scotland.

However, fire safety depends on more than just the insulation. In real buildings, materials like fire-rated plasterboard provide additional protection, and the full wall build-up matters.

Natural insulation will not achieve the highest fire ratings (such as A or A1), as those require synthetic layers like foil, which can release harmful gases when burned.

Sisalwool includes a fire-retardant treatment as standard and is a safe, low-toxicity option for most residential builds. For high-rise or higher-risk buildings, other materials may be more appropriate depending on local regulations. Always check with a qualified professional for your specific project.

We tried to burn Sisalwool using a blowtorch, watch the video here.

Fire ratings are extremely important, and equally complex. We’ve untangled the nuances and broken down the key points here.

Yes - Sisalwool is THE insulation for retrofitting both residential and commercial properties. It’s ease to work with, moisture resistant properties and breathability make it the perfect choice for any retrofit project.

Typically wherever you have timber studs, Sisalwool can be used in-between. This could be in a wall, a pitched roof, or even under a suspended timber floor.

Yes, that's one of the strengths and why it's perfect for retrofit projects, saving space and making installation simple.

The insulation can be friction fitted between the joists. No netting or other systems are required.

Sisalwool has been used in numerous builds. Some van builders like it because it
can be used without a vapour barrier and doesn’t cause problems when moisture
gets into the van through leaks and seals, others love that it's low carbon and made from recycled natural fibres.

Yes, Sisalwool can be used on a boat, we would recommend attaching a waterproof membrane to the hull prior to installation.

No, although a specialist insulations saw (we recommend the Bahco Insulation saw) will give a neater cut than a general purpose wood saw.

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For most loft floors, Sisalwool Loftroll is the ideal choice. It’s designed to be rolled out easily between joists, making installation quick and easy – especially for DIY projects. If your loft space has irregular gaps or you need a snugger fit around obstacles, then Sisalwool slabs may work better. Both options are safe to handle, breathable, and provide excellent thermal and acoustic insulation – so it really comes down to the shape of your space and how you plan to use it.

No, Sisalwool is easy and pleasant to use and can be installed successfully by anyone following the provided installation guides.

Sisal fibres have a naturally breathable structure that allows vapour to pass through, helping regulate indoor humidity and reduce the risk of condensation or mould. Combined with wool’s ability to absorb and release up to 30% of its weight in moisture without feeling damp, Sisalwool insulation helps maintain healthy indoor environments – ideal for traditional buildings that need vapour openness and long-term stability.

Yes, Sisalwool is ideal for acoustic insulation! Our 100 mm slabs have a Class A certification, meaning they typically absorb 90-100% of sound energy.

Our 50mm slab carries a Class B certification indicating it effectively reduces noise levels, echoes and reverberation within a space. 

We recommend using Sisalwool insulation internally within the building for a wide range of applications including roof, wall and floor insulation for temperature control and acoustic benefits. It is particularly suited to use in traditional buildings due to its breathability and unique friction fit capability. 

Some people like to use them to sit on or cuddle with. We’ll leave that decision up to you!

No, it is much safer and more pleasant to work with than most insulation products, so unless you have a wool allergy, Sisalwool should be - dare we say it - an enjoyable experience. 

Yes, although due to fire regulations it is not certified for use in buildings more than 18m tall or in boundary walls (like in-between flats).

You can find them on each product page and can also be viewed and downloaded here

Yes, some funding is available from Home Energy Scotland / Business Energy Scotland & The Great British Insulation Scheme

At the moment our sample boxes are made to house the exact size of our 100mm slab and to keep the shipping costs low so we don’t require passing them on to you, the customer. We are regularly reviewing our sample boxes for effectiveness and sustainability. 

We endeavour to post the samples the same day or following day depending on when the order is placed using Royal Mail Tracked 48 delivery.

100mm sample = 230mm x 160mm x 100mm

50mm sample = 230mm x 160mm x 50mm

Yes, a Bahco High Speed Steel Sharpener is included with each saw purchase. 

The Bahco Insulation saw blade is 500mm in length and .83mm width.

We like to sharpen the saw after every two - three bats are cut. This isn’t necessary, however it’s quick and easy to do and keeps the saw cutting smoothly and almost effortlessly.