Backland Development
0800 088 6248Free to call Free plot appraisal

Build a home for family in your garden in Portland

The first question for any family in Portland thinking about building in the garden is usually this: annexe or proper house? The answer turns on the person moving in, how long they’re likely to stay, and whether you might ever want to sell or let the building on its own.

An annexe is used with your home and usually tied to it by condition. A separate dwelling stands alone, with its own permission and potentially its own title. Dorset Council assesses them on different terms, and council tax, CIL and VAT rules split along the same line. Our free plot appraisal sets out both, so you can decide with your family and your advisers.

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Single-storey garden home with wide glazed doors and a covered porch at the back of a family garden
Planning authority
Dorset Council
Postcodes
DT5
Noon sun, 21 March
About 39°
Shadow from a 5 m eaves line
About 6.1 m
Planning plan
Local Plan
County
Dorset

What shapes a plot in Portland

Daylight matters twice over when the new home is for a relative who spends much of the day indoors. At noon on 21 March the sun in Portland is about 39° above the horizon, so a two-storey eaves line around 5 m high casts a shadow of roughly 6.1 m. A single-storey annexe with eaves at half that height casts one about half as long, which is one reason low buildings often sit more easily in a garden. By late December the midday sun climbs only about 16°, so we test winter light on both homes, and on next-door gardens, before the layout is fixed.

Section showing noon sun and shadows in Portland: about 39 degrees on 21 March and 16 degrees on 21 December21 m21 Mar, noon: sun 39°, shadow 6.1 m21 Dec, noon: sun 16°, shadow 17.4 mExistingNew home
This section is worked out for the latitude of Portland: around 39° of sun at midday in late March and about 16° at midwinter. It shows why the gap between your house and a new home behind it is about light as well as privacy. Garden assumed to face north.

What happens next in Portland

Getting started in Portland costs nothing. Send us a few photos of your garden and the way in, or simply call, and we’ll look at the plot from the desk and talk through your family’s plans. If there’s a realistic scheme, we arrange a site visit. Survey and design are quoted in writing before you commit, and the build price follows once the design is settled.

  1. Free plot appraisal

    We look at your plot, access and the planning picture from the desk, talk through who will live in the new home, and visit if it looks viable. There’s no cost and no obligation.

  2. Annexe or separate home

    We set out both routes for your plot, covering what each means for planning, ownership, council tax, CIL and VAT, so you can decide with your family and advisers before design starts.

  3. Survey and design

    A measured survey, then a design built around the person moving in: step-free routes, a ground-floor bedroom if needed and privacy for both households. You get a written quote after design and survey.

  4. Planning and approvals

    We prepare and submit the planning application and manage it with the council, which makes the decision. Before work starts, approval under the Building Regulations is in place and any CIL exemption has been claimed.

Worth checking early

  • Planning is the council’s decision, and an annexe is not a way round the rules that apply to a new house.
  • Family plans change: agree ownership, costs and what happens if circumstances change in writing, with a solicitor.
  • An annexe tied by planning condition usually can’t be sold or let separately, which limits flexibility later.

Portland: questions to ask

How much garden do I need for a family home in Portland?

There’s no fixed figure. A single-storey annexe close to the house can work on a smaller plot than a separate dwelling, which needs its own garden, parking and access. What matters is whether Dorset Council can be satisfied on privacy, daylight and the space left for both homes. The free appraisal gives you a first view based on your plot’s actual shape and access.

Can I reclaim VAT on a family annexe in Portland?

Often not. HMRC’s guidance gives an annexe that can’t be used or sold separately from the main house as an example of work that can’t be zero-rated, and the DIY housebuilders refund scheme asks the same question. A separate dwelling is usually treated differently. Take advice from a tax adviser before you settle the planning route, because the wording of the permission matters.

How long will building work disrupt my home in Portland?

A single garden home usually takes several months on site, with the noisiest work, such as groundworks, drainage and heavy deliveries, concentrated near the start. We agree working hours, access and parking with you up front, and with the people next door where it affects them, so your household knows what each week will look like.

Is CIL payable on a family home in Portland?

Only if Dorset Council has adopted the Community Infrastructure Levy, which its website will confirm, and we check it for you during the appraisal. Where it applies, self-build and residential annexe exemptions exist, but both must be claimed before work starts and can be withdrawn if the home is sold or let within three years of completion.

Other options in Portland

Family home in your garden near Portland

Find out what your garden could become

Free garden plot appraisal. No cost, no obligation, and a straight answer if it won’t work.

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