BayWrap

A standard 7m² canted bay with 100mm hemp insulation and clay tile finish starts at around £2,800. Larch cladding starts at approximately £3,400 and cork at approximately £4,000. Larger bays, double-storey bays, complex geometry, or any structural remediation are priced individually after a site visit.

It depends on whether your property is in a conservation area.

Outside a conservation area, external insulation and cladding to a bay window generally falls within permitted development — meaning no planning application is needed. That said, the material choice matters. A finish that reads as broadly similar in character to the existing exterior sits on more straightforward ground than a significant visual departure, and it's always worth a quick check with the local authority before work starts.

In a conservation area, planning permission is required. This doesn't mean the work can't go ahead; it means it needs to go through the application process, and the choice of finish matters. Clay tile tends to read most sympathetically to planning officers because it draws on the same material language as traditional roofscapes. We can advise on what's likely to be appropriate for your specific property and area.

Listed buildings are a separate category and require listed building consent. We'd assess these individually.

If you're unsure whether your property is in a conservation area, we can tell you at the initial enquiry stage.

None. The entire installation is done from outside. We work from scaffolding or access equipment, so there's no need to move furniture, clear rooms, or have trades walking through your home. The only interior access we'd ever need is to check window reveals or confirm airtightness membrane positions before we start — and that's a brief survey visit, not a working day inside.

For some sections of a bay window — for example where the base of the bay is brick at ground floor level — internal treatment can be the right approach, and we carry it out to the same standard as external work.

The process is more involved for the household than an external installation. We'll need access to the room, furniture moved back from the bay, and a clear working area for the duration. The work itself is relatively contained — typically a day or two per room depending on complexity — but there will be some dust and the space will be out of use while we're in it.

We use the same insulation and airtightness membrane specification internally as we do externally. The main practical difference is that the finish is a lined and decorated internal surface rather than an external cladding, and the finished depth reduces the internal reveal slightly.

Because the bay is being opened up anyway, it's also a good moment to think about what else could be improved in the same visit. If there's a radiator positioned in the bay — common in older terraces — we'd recommend upgrading it at this stage. It's also a natural opportunity to consider bespoke storage built into the bay recess: window seating with lift-up lids, shelving, or a fitted seat are all things we can incorporate or coordinate with a joiner at the same time, making the most of what's often an underused part of the room.

Where a job involves both external and internal elements, we coordinate the sequence so the airtightness layer connects properly across the junction.

Insulation materials that can't handle moisture can cause problems over time. Hemp is vapour-open, which means moisture can pass through it and disperse rather than accumulating at the cold face of the wall. Foam-based insulants don't offer this. Hemp also performs well thermally (λ=0.038 W/mK) comparable to mineral wool, sequesters carbon during growth, and in our case is grown in North Yorkshire and turned into insulation in the Scottish Borders — so the supply chain is short and traceable. It's a certified, well-proven material, not an experimental one.

We're based in Leeds and currently work across Yorkshire and Lancashire. If you're outside that area and interested in the work, get in touch — we're happy to discuss what's possible.