Single-storey extensions in Knowle

Before your single-storey extension in Knowle

Planning applications and lawful development certificates for Knowle go to Solihull Council. Many single-storey extensions fall under permitted development, but not every house keeps those rights — conditions on newer estates, conservation areas and Article 4 directions can remove them. The structural work also needs Building Regulations approval, through the council's building control team or a registered building control approver.

Every extension needs Building Regulations approval, even when planning permission isn't required.
Under permitted development, a rear extension on a semi or terrace can usually project 3 metres from the original back wall, or 6 metres through the prior approval route.
If you're building over or near a public sewer, the sewerage company has to agree before the foundations go in.

Postcode district: B93
Planning and building control: Solihull Council
From our West Bromwich base: 14 miles

Options to consider in Knowle

Rear kitchen-diner extension

The usual layout: a 3–6 metre extension across all or part of the back wall, with the old rear wall replaced by a steel beam so the new and existing rooms become one space. Roof lights or a lantern bring daylight into the middle of the house, and bifold or sliding doors open onto the garden.

Flat roof or pitched roof

Flat roofs, usually GRP fibreglass or EPDM rubber, keep the height down near boundaries and suit roof lanterns. Pitched or lean-to roofs with tiles to match the house look more traditional and shed rain faster, but need more height. The choice affects permitted development limits, cost, and how much light reaches the existing rooms.

Guide prices for Knowle

For a home in Knowle, our guide range is £28,000–£90,000 depending on size and specification. A 4 m × 5 m rear extension on a semi, with roof lights and bifold doors: usually £40,000–£52,000.

Guide prices for single-storey extensions
Option	Guide price	Good to know
Small rear or side extension (10–15 m²)	£28,000 – £40,000	Utility, WC or a modest kitchen extension
Rear kitchen-diner extension (18–25 m²)	£38,000 – £58,000	The glazing spec moves it within the range
Wrap-around or large extension (30 m²+)	£58,000 – £90,000	More steel and roof, and normally a planning application

Guide ranges include VAT where it applies. Your fixed price for the agreed specification follows a free survey at your Knowle address.

Single-storey extensions in Knowle: common questions

What guarantees come with the extension?

Windows, doors, roof lights and roofing membranes come with manufacturers' guarantees, and the terms for each product are set out in your quote. Building control's completion certificate confirms the work met Building Regulations when inspected. If anything in our workmanship isn't right after handover, call us and we'll come back and look at it. Ask us for current insurance details with your quote.

Do you cover Knowle?

Yes. Knowle (B93) is about 14 miles from our West Bromwich base and inside the area we cover. Call 0800 088 6248 or send the form on this page to book a free survey.

Do I need to tell my neighbours about an extension?

You don't need their permission for permitted development, but you will usually need to involve them. Under the prior approval route the council writes to adjoining neighbours and gives them 21 days to comment. If the build is on the boundary or the foundations are deep and close to their house, the Party Wall Act requires formal written notice. A friendly conversation before any notice arrives usually makes everything smoother.

Does Solihull Council need to approve my single-storey extension?

Usually building control, and sometimes planning. Solihull Council is the planning authority for Knowle; Building Regulations approval comes from its building control team or a registered building control approver. We'll tell you which applies after the survey.

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Book a free survey in Knowle and we'll measure up, check the drains and boundaries, and give you a written, itemised quote.