Single storey extensions, across West Yorkshire
Calder Windows - Single Storey Extensions
If a conservatory or orangery isn’t enough and you need a full room that reads as part of the house, a single storey extension is the answer. We design and build single storey rear, side, and wraparound extensions across West Yorkshire, from initial conversations through planning, build, and final handover.
Over 30 years building for West Yorkshire homeowners, and still the work we’re most often asked about.
What a single storey extension actually gives you
It sounds obvious, but it’s worth saying. A single storey extension is a full-build addition with proper walls, a proper roof, proper insulation, and a room that’s indistinguishable from the rest of the house once it’s finished. It’s not a conservatory with a solid roof. It’s not a glorified orangery. It’s an extension.
That matters because:
You can put a kitchen in it with all the services (water, gas, drainage, electrics) designed into the build
It reads as part of the house to valuers, estate agents, and future buyers
It adds real value rather than just “additional living space”
There are no compromises on heating, cooling, or year-round use
Planning, building control, and certification is treated properly as a structural addition
When to build an extension rather than a conservatory or orangery
You want a kitchen extension
Conservatories and orangeries can have kitchens in them, but an extension is where it really works. Full services, solid walls for appliances and cabinets, proper ventilation, and no thermal concerns around the cooker.
You want multiple rooms
A big enough extension can give you a kitchen, dining area, utility, and downstairs WC in one build. Hard to do that in a glass room.
You want upstairs space too
A two-storey extension isn’t covered on this page (it’s a different quote and build complexity), but we do them. Ask us if it’s what you’re actually after.
Year-round use is non-negotiable
Extensions are warm, cool, and lived-in 12 months a year by default.
You want to add meaningful value
A well-designed, well-built single storey extension typically returns more of its build cost in property value than a conservatory does. Not always, and location matters, but it’s usually the case.
Permitted development vs full planning
Most single storey rear extensions qualify under permitted development rules if they stay within the size and height limits set by current regulations. That means no full planning application, no neighbour consultations, and a faster start date.
Permitted development limits (standard, not exhaustive)
- Rear extensions on semi-detached or terraced: up to 6 metres projection with prior notification
- Rear extensions on detached: up to 8 metres projection with prior notification
- Maximum ridge height: generally no more than 4 metres for a pitched roof
- Cannot extend beyond the side wall of the original house (for side extensions)
- Cannot exceed 50% of the area around the original house
- Listed buildings, conservation areas, and some designated areas have different rules
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We check permitted development eligibility for every project. If your build needs full planning permission, we’ll tell you upfront and guide you through the application.
Design choices
Roof style
Pitched tiled roof (most traditional), flat roof with modern finishes, or a hybrid with a roof lantern over a dining area. All are available. Most of our Yorkshire extension builds go with a pitched roof to match existing house style, with flat roof sections where they specifically suit the design.
Glazing
Large bifold or sliding patio doors opening to the garden are almost always part of the brief. Full-height fixed glazing, corner glazing, or roof lanterns can all be included. Every glazed element is specified to hit modern thermal performance.
Exterior finishes
Matched brick (most common on Yorkshire builds), rendered finish, stone cladding, or a mix. We source brick carefully and lay to blend with the existing house.
Interior finishes
Plastered walls and ceiling, flooring to your spec, and full electrical and plumbing first and second fix. We can take the build to second fix ready for your kitchen fitter and decorator, or manage the finishes ourselves.
What’s involved in the build
- Initial chat and site visit to understand what you want, what the site allows, and what your budget expectations are.
- Drawings and design development working through layout options and elevations.
- Planning permission or permitted development prior notification handled by us.
- Building regulations approval and structural calculations.
- Written quote with a clear cost breakdown and timeline.
- Groundworks and foundations including drainage rerouting if needed.
- Structural walls and openings with proper lintel specification.
- Roof build with insulation, membrane, and finish.
- Windows and doors installation.
- Plastering, electrics, plumbing and internal finishes.
- Snagging, final clean-down, and walk-through.
- Certificates and guarantee documentation.
Typical build time: eight to sixteen weeks on site, plus the design and planning phase before the build starts.
FENSA-registered for windows and doors, CERTASS certified, Secured by Design on qualifying products, building regulations signed off.
West Yorkshire ground conditions
It’s worth calling out. The ground under many West Yorkshire homes is clay, and some properties sit on former industrial land, mine workings, or sloping gardens. Foundations for an extension have to account for all of this, and it’s one of the areas where cheap builders cut corners.
We specify foundations properly, do the ground investigations where they’re needed, and don’t start building above ground until we’re sure what’s below it is going to hold.
Where we build extensions
All across West and South Yorkshire. Most of our extension work is in Wakefield, Leeds, Bradford, Harrogate, Huddersfield, Halifax, Barnsley, Doncaster and the surrounding villages.
Extension FAQs
Do I need planning permission?
Most single storey rear extensions qualify under permitted development. We check every project and handle the prior notification process. If you do need full planning, we’ll guide you through.
How long does a single storey extension take?
Eight to sixteen weeks on site for most builds. Larger or more complex projects take longer. We give you a proper timeline before the build starts.
How much does an extension cost?
It depends on size, finishes, groundworks, and glazing specification. We’ll give a written quote after a free site visit. We don’t guess at prices over the phone.
Can I live in the house during the build?
Yes. We work to minimise disruption and protect the inside of the house during the build. The kitchen is usually the trickiest room because its walls are often where the new opening goes, and we’ll plan around that.
Do you handle planning and building control?
Yes. We manage the planning side, the building regulations, and the certificates at the end.
Can I add an extension to a listed building?
Yes, but listed building consent will be required, and the design constraints are significant. We’ll tell you honestly if we’re the right team for the specific project.
Related Pages
Traditional conservatories
Contemporary orangeries
Flat roof orangeries
Warm roof conservatories
Replacement conservatory roofs
Start your extension project
Come and talk to us. We’ll listen, look at your site, and tell you honestly what’s possible.
