Sheep’s wool loft insulation
Real wool, washed and treated against moths, made into rolls. It insulates about as well as mineral wool, is pleasant to handle and copes well with moisture, but it costs more.
| What it is | Sheep’s wool, cleaned and treated against insects, often blended with a polyester binder |
|---|---|
| Comes as | Rolls and slabs |
| Typical lambda | Around 0.035 to 0.040 W/mK |
| Usual depth | Similar to mineral wool |
| Moisture | Absorbs and releases water vapour without losing much performance |
| Best for | Older and traditional homes, and people who want a natural material |
Why people choose it
Wool is a natural, renewable fibre. It isn’t itchy, so it is easy to handle without heavy protective gear, and it doesn’t give off the irritating dust mineral wool can. Its biggest technical advantage is how it deals with moisture: wool can take up water vapour from the air and give it back without feeling wet or losing much of its insulating effect. That makes it a good fit for older, solid-walled houses built from materials that are meant to “breathe”.
Things to check
- Moth treatment. Wool insulation is treated to stop clothes moths and carpet beetles. Ask what treatment the product uses.
- Binder. Many products include some polyester to hold the fibres together. Ask about the blend if being fully natural matters to you.
- Cost. Wool usually costs more than mineral wool for the same performance. Our quote will show the difference.
- Fire. Wool is naturally hard to ignite, and products are treated to improve their fire performance. It is not non-combustible like mineral wool.
Where it fits best
Period and listed homes, timber-framed buildings, and any loft where the people living below want to avoid synthetic fibres. In a modern house with a well-ventilated loft, mineral wool will do the same job for less money. See our guide to insulating period and listed homes.
Thermal conductivity (the “lambda” value, in W/mK) tells you how well a material resists heat: the lower the number, the less thickness you need. Figures here are typical ranges; the product’s own declaration of performance gives the exact value.
Common questions
Is sheep’s wool better than mineral wool?
Will moths eat it?
Ready for a free loft insulation quote?
Tell us about your home and we’ll give you a written quotation before any work begins.