Types of extension we build
- Single-storey rear: the classic kitchen-diner extension opening onto the garden.
- Side return: fills in the alley beside a terrace to widen the ground floor.
- Side extension: extends out to the side for a larger kitchen or utility.
- Two-storey: adds space upstairs and down in one project.
How much does an extension cost?
Indicatively, single-storey rear extensions start from around £40,000 + VAT and rise with depth and specification; larger and wrap-around projects cost more. Our design and planning fee is £1,600 for a 3m rear extension and £2,000–£3,000 for 3–6m extensions — see pricing.
Roof and glazing options
- Flat roof with rooflights for a clean, minimal look.
- Roof lantern to flood the space with light.
- Lean-to or vaulted/pitched roof for character.
- Bi-fold or slim sliding doors, and Crittall-style glazing.
Planning for extensions
Smaller rear extensions often fall under permitted development; larger ones and those in restricted areas need householder planning permission. We confirm your route and handle the whole submission.
Recent projects
Glass-Infill Rear Extension
Open-Plan Ground-Floor Rear
Single-Storey Side Extension
Common questions
How long does an extension take?
Design and approvals take roughly 6–10 weeks, then most single-storey extensions are on site for 10–16 weeks.
How big can I build without planning permission?
Many single-storey rear extensions are allowed under permitted development within set depth limits — we confirm exactly what you can do for your property.
Do you manage the build too?
Yes — design, planning, structural and construction are all delivered by one accountable Virtue team.