Sheep Wool Loft Insulation

What sheep wool insulation is

Sheep wool loft insulation is made from natural wool fibres, cleaned, treated and formed into rolls or batts that are laid across the loft floor. The crimped structure of wool traps air, which is what slows the movement of heat. Some products blend a small proportion of other fibres to help the roll hold its shape, so it is worth checking the exact make-up on the manufacturer’s data sheet.

It is a breathable material, which is a large part of its appeal in traditionally built homes where allowing moisture to move through the structure matters.

Typical uses

Sheep wool suits a standard loft-floor installation and can also be used as a top-up over sound existing insulation. It is most often chosen for older homes and listed or traditional buildings, where a natural, breathable fibre fits the way the building was designed to handle moisture.

Main benefits

Wool is comfortable to handle, with far less of the skin and airway irritation associated with mineral fibres, so many homeowners like it in lofts they visit regularly. It is a renewable material with a low-energy production process, and its ability to take up and release moisture helps buffer swings in humidity within the loft.

Moisture behaviour

Wool is hygroscopic: it can absorb a proportion of its weight in moisture and release it again as conditions change, without a large loss of thermal performance. This buffering can be helpful, but it is not the same as stopping condensation. Damp still needs somewhere to go, so the eaves are kept clear and ventilation is considered together with the insulation rather than in isolation.

Fire and pest treatment

Sheep wool is naturally slow to ignite compared with many materials, but manufactured insulation is still treated to meet the relevant fire classification, and the data sheet states the rating for a given product. It is also treated to resist insect and moth attack. These treatments are part of why a proper insulation product differs from raw wool, and we follow the manufacturer’s requirements on handling and storage.

Thermal performance

Sheep wool’s thermal conductivity is broadly comparable to good mineral wool, so the depth needed to reach a target performance is similar. The 270mm benchmark commonly quoted for wool-based loft floors is a useful guide, but the exact build-up is confirmed against the specific product and your loft on the survey, not assumed.

Boarding implications

Like any soft wool, it must not be crushed. Boards laid straight onto the joists will compress the fibres and reduce performance. Where storage is wanted, a raised boarding system keeps the deck clear of the insulation so its depth is preserved.

Sustainability

Wool is renewable and, at the end of its life, is a natural fibre rather than a synthetic one. For homeowners who weigh the environmental profile of a material alongside its performance, that is often a deciding factor.

Cost factors

Sheep wool typically costs more per square metre than mineral wool, which is the main trade-off. The installed price also depends on the loft area, access and build-up — the cost guide explains the factors, and an assessment gives you an accurate written quotation. Work is covered by our guarantee, and depending on the service and location, work may be completed by The Insulation Company or an approved installation partner.

A note on suitability

Sheep wool is a good option for many older and breathable buildings, but it is not chosen on the age of a property alone. The right material for your loft depends on the roof, the existing insulation and any signs of moisture, all of which are confirmed on an inspection.