A Victorian terrace, a 1930s semi and a new-build mews need different windows. We make casement, tilt & turn, sliding sash, steel-look and fixed windows in aluminium, timber and PVC, and help you pick what the building, the planners and the budget will accept.
The everyday British window. Sashes open outwards on friction stays, so they don’t take up room inside. A flush sash sits level with the frame for a cleaner, more traditional face. Stepped sashes are simpler and cost less.
One handle, two ways to open. Tilt the top in for secure ventilation, or turn the whole sash in to clean the outside from the room. Ideal for flats and upper floors, and for big single panes where outward-opening sashes would be too heavy.
London’s signature window. We make timber sashes with the proportions, horns, run-through or stuck-on bars and slim double or vacuum glazing that conservation officers look for. PVC sashes are a cost-effective option outside conservation areas.
The industrial look of old steel windows, in thermally broken aluminium. It suits warehouse conversions and modern extensions, and can replace original metal windows where the planners will accept aluminium, without the cold frames and condensation of single-glazed steel.
Where you want a view, not a vent. Fixed panes can be much larger than opening sashes and have the slimmest frames. We combine them with opening sashes or vents so the room still meets the ventilation rules.
Typical figures for a casement window. Your quotation gives the certified values for your sizes and glass. Indicative
| Aluminium | Timber | PVC | |
|---|---|---|---|
| U-value, double glazed | c. 1.3–1.6 W/m²K | c. 1.2–1.4 W/m²K | c. 1.2–1.4 W/m²K |
| U-value, triple glazed | c. 0.9–1.1 W/m²K | c. 0.8–1.0 W/m²K | c. 0.7–1.0 W/m²K |
| Frame and sash face width | c. 65–90 mm | c. 90–120 mm | c. 100–120 mm |
| Upkeep | Wash twice a year | Wash; recoat every 6–10 years | Wash twice a year |
| Typical service life | 40 years or more | 40–60 years, maintained | 25–35 years |
| Relative cost | ££–£££ | ££–£££ | £ |
| Conservation areas | Steel-look can replace metal windows, case by case | Usually preferred; often required for sashes | Often resisted; check for an Article 4 direction |
We check these at drawing review and say in writing how each window complies. Planning comes first: in a conservation area or a listed building, you may need consent before anything else.
Listed buildings need listed building consent for new windows. Many London conservation areas have Article 4 directions that remove the right to change windows on front elevations without permission.
Replacement windows in existing homes need a U-value of 1.4 W/m²K or better, or Window Energy Rating band B. New homes are designed to a notional 1.2 W/m²K.
First-floor habitable rooms usually need an escape window: a clear opening of at least 0.33 m², at least 450 mm wide and high, with the bottom no more than 1,100 mm above the floor.
Replacing windows must not reduce the background ventilation a room had before. We fit trickle vents in the head where they are needed, sized for the room.
Safety glass in low and critical locations, guarding for low sills, and restrictors where Part O limits openings in new homes.
Ground-floor and easily reached windows in new dwellings must be tested to PAS 24. All our window systems are specified to it.