Conservatory Conversion

Planning permission almost certainly not required. Replacing the conservatory walls and glazing with a solid timber frame structure is an alteration to an existing building, and provided you're not increasing the footprint or height, it falls comfortably within Permitted Development. Building Regulations this is where it gets more nuanced, and the honest answer is yes, Building Regs will likely apply, for a few reasons: Change of use converting from a conservatory to a habitable WC/utility room is a material change. Conservatories have historically been exempt from Building Regs partly because they're not treated as habitable space. Once you're fitting a WC and using it as a utility room, that exemption falls away. Structural work replacing dwarf walls and the glazed envelope with a timber frame is a structural alteration, which triggers Building Regs regardless of use. Drainage/plumbing — adding a WC means connecting to the foul drain, which requires Building Regs sign-off under Part H. Thermal performance — the new solid walls will need to meet current U-value requirements (Part L). The existing tiled roof may also need upgrading insulation-wise once the space becomes conditioned. Ventilation — a WC requires mechanical or openable ventilation compliant with Part F. The existing roof keeping it is fine from a planning perspective, but Building Control will likely want confirmation that it's structurally adequate to bear the loads now that the supporting walls underneath are being rebuilt. A structural engineer's sign-off may be needed, or at minimum BCO satisfaction on inspection. Blocking the internal glazed doors straightforward, no issues there provided the new doorway into the house remains the primary means of access. Bottom line: Submit a Building Regs application (Full Plans route is better than Building Notice for this one, given the drainage and structural elements). Planning permission not required under normal PD rules, but worth a quick call to your local authority to confirm nothing unusual applies to the property. Kind Regards Abie