Portland, Dorset
Two-storey rear extension in Portland
Thinking about a two-storey rear extension in Portland? A larger kitchen downstairs and an extra bedroom or bathroom upstairs, under one roof. Our team handles the drawings, the planning route and the build, and your contract is with one company throughout.
Portland sits in Dorset, with postcode districts including DT5. In Portland, a two-storey rear extension is worth comparing with the cost of moving once stamp duty, agents' and legal fees are counted.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a two-storey rear extension cost in Portland?
For Portland we work from the South West England rate: £1,870–£2,810 per square metre of new floor, including VAT, standard specification. South West prices run slightly above our West Midlands baseline; natural stone to match the house is the main variable.
| Size | Guide price inc VAT |
|---|---|
| 3 m × 5 m footprint, two floors (30 m²) | £56,000–£84,000 |
| 4 m × 6 m footprint, two floors (48 m²) | £90,000–£135,000 |
Your written price follows a measured survey and an agreed design, so it reflects your house, not an average.
Do you need planning permission for a two-storey rear extension in Portland?
Whether your two-storey rear extension in Portland needs a planning application depends on its size, your house and any local restrictions.
A two-storey rear extension can be permitted development in England only if it projects no more than 3 metres, stays at least 7 metres from the rear boundary, matches the existing roof pitch and has obscure-glazed upper side windows. In practice most double-storey rear extensions go through a householder planning application.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. We check your house's planning history and any conservation area before drawing, so the route is clear before you spend on plans.
What are homes in Portland like to extend?
Stone-built and rendered houses are common around Portland, so matching the walling is a design decision in its own right: natural stone, reconstituted stone or a render finish across old and new.
How a two-storey rear extension in Portland comes together
Look round and measure
A free visit to see the back of the house, measure it, check the drains and boundaries and hear what you need.
Drawings and budget
Floor plans and elevations for the options, each with a guide price.
Planning and regulations
We take the design through the right planning route, then produce the construction drawings and engineer's calculations for building control.
Build and sign-off
We build to the approved drawings with regular updates, then hand over the building control completion certificate and any guarantees from suppliers.
Two-storey rear extensions near Portland
From Portland, the nearest places we also cover are Weymouth (3.3 miles) and Dorchester (10.3 miles).
- Two-storey rear extension in Weymouth
- Two-storey rear extension in Dorchester
- Two-storey rear extension in Bridport
- Two-storey rear extension in Swanage
- Two-storey rear extension in Poole
Other work in Portland:
FAQ
Two-storey rear extension questions in Portland
Can I live at home while the extension is built?
Usually yes. Most of the work is outside until the back wall is opened near the end, and that stage is screened off.
Is the site visit in Portland free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.
What is the 45-degree rule?
Many councils check that a two-storey extension does not cross a 45-degree line drawn from the nearest habitable window of the neighbouring house. We test it at the first drawing.
What postcode areas do you cover around Portland?
Including DT5, and the surrounding Dorset area.
Can I get a price without a visit?
Our online guide-price tool gives a range in a couple of minutes. A written price needs a survey.
How much does a two-storey rear extension cost in Portland?
As a guide, £1,870–£2,810 per square metre including VAT for a standard specification. For example, 3 m × 5 m footprint, two floors (30 m²): about £56,000–£84,000 at that rate. Your written price follows the survey.