Guides to windows, doors and the rules in London.
Each guide answers one question: which door to choose, what the Building Regulations ask for, and what changes in a conservation area. Every guide shows the date it was last updated.
Extensions: doors, roof glazing and the rules
For homeowners planning an extension, and for architects comparing systems.
Bi-fold or sliding doors?
How much of the wall opens, what you see when the doors are closed, sealing, everyday use and stack space in a London extension.
Large sliding doors in London
Beam deflection, flush thresholds, glass weight and handling on terraced streets, and Approved Documents L, O, K, M and Q.
Planning for bi-fold and sliding doors
When new doors need planning permission: permitted development, extensions, conservation areas, flats and Building Regulations.
The 25% glazing rule
What counts towards the glazing limit for extensions, a worked example, U-value limits and what to do if you go over.
Roof lantern or flat rooflight?
Light, look, rain and cleaning, overheating, Part L U-values and the 25% glazing rule.
What affects the price
Size, system, glass, thresholds, access and installation: what drives the price of windows and doors, and where to save.
Period homes and conservation areas
Repair, replacement and glazing that conservation officers accept.
Steel windows in conservation areas
Original steel (Crittall-style) windows in a conservation area or listed building: repair, secondary glazing, consent and Part L.
Aluminium or steel windows?
Sightlines, insulation, condensation, durability and cost of steel and steel-look aluminium.
Slim double or secondary glazing?
Slim double, vacuum or secondary glazing for period windows: look, heat, noise and consent.
Rules, certificates and security
What the Building Regulations, planning and your lease ask for.
Replacing windows
What replacement windows in an existing home must meet: Part L U-values, Part F ventilation, Part B escape, Part K safety glass and certification.
Windows in a leasehold flat
The lease, the landlord’s consent, planning for flats, Building Regulations and fire safety.
FENSA and window certificates
What competent person schemes cover, when building control is needed, and what to do about a missing certificate.