If you work with older or listed buildings, you’ll know the usual tension: improve comfort and energy performance, but don’t compromise the fabric. That balance sits at the heart of everything we do with Sisalwool natural fibre insulation.
Sisalwool is a breathable, natural fibre insulation made from sheep’s wool and recycled sisal fibres, designed to work with traditional construction rather than against it. It’s comfortable to handle, easy to fit into irregular spaces and helps you manage moisture safely in solid walls, roofs and floors….exactly where many conservation architects are most cautious about introducing insulation.
We’re keen to build longer‑term relationships with conservation practices who are looking for low‑risk, fabric‑friendly ways to tackle heritage retrofit and energy efficiency. That’s why we’ve invested not just in the product, but in training, case studies and technical support created with your kind of projects in mind.
Why natural fibre insulation fits conservation work
Older buildings were designed to breathe. When you add impermeable materials and closed‑cell insulation into that mix, you can easily trap moisture where you don’t want it.
Natural fibre insulation offers another route: vapour‑open, hygroscopic and sympathetic to lime, stone, brick and timber.
Sisalwool helps to:
- Support moisture movement, reducing the risk of interstitial condensation and damp in solid walls and roofs.
- Improve thermal comfort in winter and help limit summer overheating, especially when combined with appropriate ventilation and shading.
- Cut noise transfer, which is increasingly relevant in mixed‑use and residential conversions.
- Lower embodied carbon compared to many synthetic insulation products, while reusing waste wool and coffee‑sack sisal fibres.
Because it’s soft, non‑itchy and low‑toxicity, Sisalwool is also straightforward for contractors to work with on site, without specialist PPE or special handling procedures.
Recognised CPD for conservation architects
We know CPD is not a “nice to have” for conservation professionals, it’s an essential part of practice.
Sisalwool has been appointed as a Recognised CPD Provider by the Institute of Historic Building Conservation (IHBC), which exists to support and accredit conservation specialists across the UK.
Our CPD on natural fibre insulation and breathable retrofit looks at:
- How vapour‑open, natural fibre insulation interacts with traditional materials and assemblies.
- Practical build‑ups for heritage retrofit—solid stone walls, timber roofs, suspended floors and internal wall insulation.
- Detailing, buildability and what contractors need on site to deliver a robust, conservation‑grade outcome.
Because the CPD is IHBC‑recognised, you can log it against your formal CPD requirements, safe in the knowledge it meets the Institute’s expectations around quality and relevance.
We can deliver sessions for individual practices, local authority teams or mixed conservation groups, online or in person, and we’re happy to frame the conversation around live projects you’re working on.
Real projects: Sisalwool in heritage retrofit
Rather than talk in abstracts, here are a couple of examples of natural fibre insulation in action on real buildings.
#1 Solid granite home: tackling damp and comfort together
In a historic granite home in the north‑east, the brief was familiar: deal with persistent damp and cold internal environments, without compromising the character of the property. The design team needed a breathable insulation that would sit comfortably with solid masonry and traditional finishes.
Sisalwool was used as part of a natural internal wall insulation build‑up, allowing moisture to move safely through the fabric while improving thermal comfort. The result was a warmer, more stable internal environment and reduced reliance on constant heating, without resorting to impermeable layers or synthetic insulants.
#2 Pre‑1919 solid wall retrofit: lime, breathability and detail
On a pre‑1919 solid wall house, the project team stripped out later, non‑breathable interventions and went back to the original construction. Floors were rebuilt with a limecrete slab and capillary‑breaking layer, and walls were lime‑parged to improve airtightness before natural insulation was installed.
Sisalwool insulation was pressed between joists and studs, then finished with wood fibre boards, delivering better thermal performance and airtightness while staying firmly in line with conservation‑led best practice. Careful moisture management—checking ground levels, masonry condition and ventilation—meant the retrofit improved comfort without introducing new damp risks.
Working with conservation architects, not just supplying product
We don’t see Sisalwool as a “drop‑in” product; we see it as part of a conversation about how to retrofit old buildings well. That means being available early, listening to the constraints of the building and the brief, and offering honest guidance on where natural fibre insulation is (and isn’t) the right answer.
If you’re exploring breathable insulation, natural fibre insulation or heritage retrofit options for a current or upcoming project, we’d be very happy to talk things through. Whether it’s a quick sense‑check on a detail, a practice‑wide CPD session or a deeper dive into build‑ups for a tricky solid wall or roof, we’re here to support you and your clients for the long term.
We’d love to hear from you.
Drop us a line with a current or upcoming project, and we can talk through options, share relevant case studies and arrange an IHBC‑recognised CPD session tailored to your team.
la colección de lana de sisal
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