How much does a wrap-around extension cost?

In Dorset, budget £55,000–£100,000 for the build plus £3,000–£6,000 in professional fees. Wrap-arounds offer good value per m² because of the shared structure at the L-junction.

Do I need planning permission for a wrap-around extension?

In most cases, yes — the side element typically requires planning permission. We can sometimes split the project into a PD rear element and a planning application for the side, depending on your property and timelines.

How long does a wrap-around extension take to build?

The build takes 14–20 weeks. With design and planning, the total project timeline is 7–10 months from first contact to completion.

Is a wrap-around better than just a rear extension?

If you have side space to use, a wrap-around creates significantly more living area for relatively modest additional cost (the side wing shares foundations and roof drainage with the rear). It is the best option for maximising ground-floor space.

Wrap-Around Extension Guide: Cost, Planning & Design in Dorchester

Q: Do I need planning permission for a wrap-around extension guide: cost, planning & design in Dorchester?

It depends on your specific property. Dorset Council covers a large rural area with many villages in conservation areas and AONBs (Dorset AONB, Cranborne Chase AONB). Permitted Development rights may be restricted in these areas — always check before assuming PD applies. Dorset Council approves approximately ~87% of householder applications. We assess your project and property designations before recommending the planning route — many Dorchester homeowners find they only need a Certificate of Lawfulness (£1,500).

A wrap-around extension combines a side return and rear extension into one L-shaped space. It is the most ambitious single-storey option, typically creating a large open-plan kitchen-living-dining room that wraps around the corner of the house. Here is what Dorchester homeowners — covered by Dorset Council — need to know about costs, planning, and timelines.

Local cost range — Dorchester

£1,700–£2,500/m²

Dorchester build costs are mid-range for Dorset. Poundbury extensions must follow the Duchy of Cornwall design code, which specifies traditional materials and construction methods.

Wrap-Around Extension Guide: Cost, Planning & Design rules in Dorchester

Dorchester falls under Dorset Council (Dorset Council). Dorset Council covers a large rural area with many villages in conservation areas and AONBs (Dorset AONB, Cranborne Chase AONB). Permitted Development rights may be restricted in these areas — always check before assuming PD applies.

Planning applications (annual)

~6,000

Average decision time

8–10 weeks

Approval rate

~87%

AONB coverage

Extensive

Fixed prices, no surprises

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What you need to know

What is a wrap-around extension?

A wrap-around extends your home on two sides — typically the rear and one side — forming an L-shape when viewed from above. This creates the maximum ground-floor space from a single project. It works particularly well on corner plots and semi-detached properties with side access.

Design possibilities

The L-shape naturally creates distinct zones: a kitchen area in one wing, a dining space in the corner, and a living area in the other wing. Bi-fold doors across the rear connect the space to the garden. Corner glazing where the two wings meet adds dramatic natural light.

Planning and PD

The rear element may fall under PD (up to 4m/8m). The side element typically requires planning permission unless it stays within the existing side wall plane. We assess each wing separately and advise on the most efficient route — sometimes a hybrid approach (PD for the rear, planning for the side) saves time.

How much does it cost in Dorchester?

Local Dorchester rates: £1,700–£2,500/m². The table below shows national Dorset figures for reference.

Item	Typical Cost Range
Build cost (25–40m²)	£55,000–£100,000
Professional fees	£3,000–£6,000
Corner glazing	£3,000–£8,000 extra
Kitchen	£10,000–£30,000
Party wall (per neighbour)	£700–£1,500
Contingency (15%)	£8,000–£15,000

Prices based on Dorset rates, 2026. Local Dorchester range: £1,700–£2,500/m².

Planning permission in Dorchester

Wrap-around extensions usually require planning permission for the side element, even if the rear element falls under PD. We recommend applying for the full project under one planning application for simplicity.

The rear wing may qualify as PD if it meets standard depth limits. Side extensions under PD must not exceed half the width of the original house and must match the existing ridge height. In practice, most wrap-arounds benefit from a single planning application.

Dorset Council — local planning context

Dorset Council covers a large rural area with many villages in conservation areas and AONBs (Dorset AONB, Cranborne Chase AONB). Permitted Development rights may be restricted in these areas — always check before assuming PD applies.

Dorset Council processes approximately ~6,000 planning applications per year, with an approval rate of ~87%. Average decision time is 8–10 weeks.

Building regulations

Complex junction between the two wings requires careful structural design. Drainage from both wings must be coordinated. The corner area where the wings meet needs particular attention for waterproofing and structural continuity.