House extensions & alterations

Outbuildings and garden rooms

Garden offices, gyms, garden rooms and the conversion of existing outbuildings into living accommodation.

Get a free quoteFrom £600 for homeowners

When an outbuilding needs planning permission

A garden building used for purposes incidental to the house can often be built as permitted development if it is single storey, covers no more than half the garden, sits behind the front of the house and is no higher than 2.5 metres within 2 metres of a boundary, or 4 metres with a dual pitched roof elsewhere. Anything with a bedroom, anything in front of the house, two storey buildings, and outbuildings at listed buildings or in conservation areas need planning permission. Converting an outbuilding to a separate home always needs a full application.

Designing a garden building

We keep garden buildings low and simple, with timber or composite cladding or brick to match the house, and place them where they do not overshadow neighbours or harm trees. Where trees are close we coordinate a BS5837 tree report and protection plan, as at 8 Pitts Lane in Earley. For conversions we reuse as much of the existing structure and roof covering as possible, which is often what makes a scheme acceptable in the Green Belt or next to a listed building.

Outbuilding projects

The projects below include a garden room in Tilehurst, a garden gym in south Reading, a two storey gym and office in Earley, a garden study in Crowthorne, a pair of outbuildings converted to a guest house next to a listed cottage in Twyford, two approved outbuildings at 20 Culver Lane in Earley, a gym and playroom in Finchampstead, and a garden gym and a summer house with an office at 50 Amblecote Road in Tilehurst.

Planning constraints we check

Garden buildings must stay incidental to the house, and their height near boundaries, the trees around them and their effect on neighbours decide whether they need permission and whether they will be approved.

Permitted development and Article 4: Classes A to E of Part 1 of the General Permitted Development Order 2015, prior approval for larger rear extensions, and Article 4 directions that remove permitted development rights in parts of Reading, Wokingham and West Berkshire.
Local Plan policies: Reading Borough Local Plan 2019 (CC7 design, CC8 amenity, H9 house extensions, H11 garden land); Wokingham Core Strategy CP3 and the Managing Development Delivery Local Plan (TB06 garden land); the Bracknell Forest Local Plan; West Berkshire Local Plan Review 2023 to 2041 (SP7 design quality); Spelthorne Core Strategy and Policies DPD 2009 (EN1); Slough Core Strategy and saved Local Plan policies; and the National Planning Policy Framework.
Design guidance: The Wokingham Borough Design Guide SPD, Reading's Residential Conversions SPD and design guidance, the Slough Residential Extensions Guidelines SPD and the Bracknell Forest Design SPD, which set rules on scale, roof form, materials, set backs and separation distances.
Neighbour amenity: Daylight and outlook tested with the 45 and 25 degree methods in BRE 209 (Site layout planning for daylight and sunlight), overlooking distances, overshadowing and the effect of new windows on neighbours' privacy.
Trees: Tree Preservation Orders and conservation area trees, root protection areas, and tree surveys, arboricultural impact assessments and protection plans to BS5837:2012 where building works come close to trees.
Ecology and biodiversity: Bat and nesting bird checks under the Conservation of Habitats and Species Regulations 2017, preliminary roost assessments where roofs or old buildings are affected, and Biodiversity Net Gain under the Environment Act 2021 with the statutory biodiversity metric (householder applications are exempt).
Flood risk and drainage: The Environment Agency flood map (Flood Zones 1 to 3), site specific flood risk assessments, the sequential test for new homes in higher risk zones, and sustainable drainage (SuDS) for surface water.
Heritage: Listed buildings and conservation areas under the Planning (Listed Buildings and Conservation Areas) Act 1990 and NPPF chapter 16, with heritage statements where needed.
Green Belt, landscape and the Thames Basin Heaths: Green Belt tests on proportionate extensions and replacement buildings, National Landscape settings, and Thames Basin Heaths SPA mitigation (SANG and SAMM contributions) for new homes within 5km.

Prices from£600 fee for the full package of documentation for our homeowner planning service

Fixed fee agreed before we start. Council application fees are paid separately. New dwellings, conversions, appeals and consultancy are quoted per project.

Questions

Can I sleep in a garden outbuilding?

Not under permitted development. Bedrooms and other primary living accommodation in an outbuilding need planning permission, usually as an annexe that stays ancillary to the house.

Can I use a garden office for work?

Yes, an office for your own use is normally incidental to the house. Regular visits from clients or staff may amount to a change of use, which we can advise on.

10 projects