Two proposed Class E outbuilding schemes at a house in Ripley, Surrey, have failed because the applicant did not adequately justify the size of the home gym. Inspector Robin Buchanan dismissed linked lawful development certificate appeals 3368625 and 3374325 on 23rd October 2026, upholding Guildford Borough Council’s decisions.
The two designs were not rejected because physiotherapy, exercise, sauna use, car storage or garden machinery were inherently inappropriate domestic activities. The Inspector accepted that these could be incidental to the enjoyment of the house. The problem was the unexplained floorspace in the proposed gym, which made the overall size of each building difficult to justify.
I think that distinction is useful for anyone preparing a Class E outbuilding application or certificate of lawfulness. An outbuilding can contain familiar household facilities and remain subordinate to the house, yet still fail if the evidence does not explain why its particular footprint is reasonably required.
Class E outbuilding plans: 88 and 77 square metres
The appeals concerned Pipkin, Grove Heath Road, Ripley, where the owner proposed an outbuilding on land beside a four-bedroom family house. Both applications sought a certificate under section 192 of the Town and Country Planning Act 1990 to establish whether the works would have been lawful on the dates of application. The first application was made in February 2025 and the second in July 2025.
Appeal A, reference 3368625, concerned a single-storey building about 17.33 metres long and 6 metres wide, with an approximately 88 square metre gross internal area. Plans showed a gym, sauna, changing room, garage with workshop space and a services room.
Appeal B, reference 3374325, proposed a shorter building, about 15.33 metres long and 6 metres wide, measuring approximately 77 square metres internally. That version replaced the garage and sauna arrangement with a garden store or tractor shed, workshop and services room, while retaining the gym. Because the designs occupied substantially overlapping positions, only one could be constructed.
The issue was not simply whether a Class E outbuilding could occupy such an area. The Inspector examined what the rooms were for, how their proposed dimensions related to those activities and whether the evidence justified the buildings as a whole.
Why the Class E outbuilding gym evidence fell short
There was medical evidence that the owner’s wife needed long-term musculoskeletal rehabilitation following spinal surgery. The Inspector regarded a home gym used for physiotherapy, including occasional visits by a practitioner, and for wider family exercise as a normal domestic activity. He also accepted that a dedicated exercise room could prevent the displacement of ordinary living accommodation.
For Appeal A, however, the drawings did not provide a gym equipment layout. The gym would occupy approaching half the building. The Inspector could not establish whether that amount of room was necessary for the intended equipment, safe circulation or future use, rather than leaving substantial surplus space.
Appeal B supplied more information, but it was inconsistent. Seven pieces of equipment were listed, while only five unlabelled equipment symbols appeared on the plan. The appellant said the illustrations were indicative and the arrangement might change. The Inspector accepted that equipment could be replaced or rearranged later, but did not regard this as enough to show that almost half the proposed Class E outbuilding was reasonably required at the outset.
It was the lack of objective justification for the gym dimensions, not a rejection of the family’s medical circumstances, that proved decisive. A smaller or better-evidenced room might have raised a different assessment, but the Inspector could not rewrite the certificate applications or substitute different drawings.
Domestic uses the Inspector did accept
The other parts of the proposals were not dismissed as excessive by default. The proposed sauna and changing room in Appeal A were considered reasonable adjuncts to the gym. A garage comparable with the property’s former garage was also regarded as reasonably required for a family car, circulation space and cycle storage.
For Appeal B, a garden store capable of housing a ride-on mower, household garden equipment, furniture and bicycles was consistent with the large rural grounds. Modest workshop space and plant rooms for services to the home and outbuilding were also accepted. Those findings show why labelling every garden building over a particular area as unlawful would be the wrong lesson.
The existing property was being extended and its former garage and studio building had been converted to a habitable annexe. The Inspector recognised that an owner need not rearrange all existing rooms or keep an old shed purely to avoid another structure. The real question remained the normal functional relationship between each proposed use and the house.
Another point matters for Class E outbuilding certificates: the house was unoccupied when the applications were made. That did not itself make the proposals unlawful. Permitted development rights attach to the land, and separate applications for possible future domestic arrangements are not automatically contradictory.
How the Class E outbuilding lawfulness test was applied
Paragraph E.(a) of Schedule 2, Part 1, Class E of the General Permitted Development Order requires the building to be provided for a purpose incidental to the enjoyment of the dwellinghouse as such. The Inspector considered the distinction between recognising an incidental domestic use and establishing that the whole of a particular building was reasonably required for it. Our Class E outbuildings guide explains the separate siting, height and other limitations on this permitted development right.
Neither national planning policy nor a development plan balance could rescue these applications. They were proposed lawful development certificate cases, not applications for discretionary planning permission. The burden was on the applicant to demonstrate lawfulness on the balance of probability at the relevant dates.
Although both designs would remain visually subordinate to the larger house and some individual rooms were justified, the unexplained gym area dictated a substantial part of each overall footprint. The Inspector concluded that neither complete Class E outbuilding met the incidental-purpose limitation. Both appeals were therefore dismissed.
There was also a question about whether vehicles could practically reach the proposed garage from the existing entrance. The Inspector did not determine that access issue, observing that any future driveway or access works would be separate matters. It would be incorrect to report this case as a refusal based on vehicle access, Green Belt harm or the mere presence of a home gym.
What to include in a Class E outbuilding certificate
My starting point would be a properly dimensioned room plan matched to the actual intended use. For a gym, identify the type and approximate dimensions of equipment, sensible safe circulation areas and why the overall space is necessary. For stores, explain the items to be accommodated, including larger machinery, rather than relying on a generic label alone.
This does not mean that a household must freeze every future furniture arrangement. It means the Class E outbuilding assessment needs enough credible detail to distinguish reasonable practical space from unnecessary surplus floorspace. Where several facilities are combined into one structure, show why that combination and total area make sense as incidental domestic accommodation.
The comparison with our Harrow outbuilding appeal is particularly instructive. Inspector Robin Buchanan allowed a 66 square metre building there on 9th October 2026 because its plans explained the equipment and clearances, but rejected a larger 94 square metre alternative. At Ripley on 23rd October, both the 88 and 77 square metre proposals failed, despite accepted medical and domestic reasons for a home gym, because its proposed floorspace was inadequately evidenced. These are separate appeal decisions, and neither creates a statutory maximum size for a Class E outbuilding. Our Teddington Class E decision concerns a different factual question.
The Inspector’s primary decisions can be accessed through the Planning Inspectorate records for appeal 3368625 and appeal 3374325. The appeal decision is also available on AppealBase.
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