Planning Permissions & Building Regulations in Hampshire, Southampton, West Sussex and the South East

Planning permissions and building regulations are a crucial aspect when considering home improvements, extensions, and conservatories. With this in mind, we’ve compiled relevant up-to-date information however, if there’s anything we haven’t covered, don’t hesitate to get in touch with an IWS expert today.

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What’s the difference between planning permission and building regulations?

In simple terms, planning permission refers to the assessment of whether the extension will conform with local and national development rules, whereas building regulations are standards that must be followed to make sure the development is safe to reside in and be around.

Do you need planning permission for replacement windows or doors in a conservation area?

Unless your property is listed or covered by an Article 4 Direction, you shouldn’t need to apply for planning permission. As experts in this field, with many timber and timber alternative windows and doors accepted in conservation areas across Hampshire and Sussex, don’t hesitate to contact us to discuss this further.

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Permanently relaxed planning permissions that apply to houses in England only

*Subject to the associated Neighbour Consultation Scheme, as of 1st June 2019, single-storey extensions that are situated outside of Designated Land and Sites of Specific Interest will not require planning permission as long as glazed extensions do not exceed 6m for attached houses or 8m on detached houses. This only applies to houses in England. Contact us for further clarification.

These permitted allowances apply to houses only.

Further clarification on planning permission guidelines can be found via the Planning Portal website.

Do I need planning permission to put a conservatory on a listed building?

Did you know that ignoring planning regulations can result in a £5,000 fine, with your new conservatory being altered or even demolished? Therefore, it’s always advisable to contact your Local Building Authority for clarification on whether you need to apply for planning permission to install or refurbish a conservatory attached to a listed building.

Hampshire County Council Planning Department

West Sussex County Council Planning Department

Get in touch to find out how you can increase your chances of getting planning approval, via specialist conservatory design support.

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Do I need planning permission for a conservatory?

As long as you meet the following conditions, your glazed extension refurbishment should remain within permitted development status (exempt from planning permission):

All single storey extensions

  • Must not cover more than 50% of the size of the original house
  • Must not be built fronting a highway
  • Must not include verandas, balconies or raised platforms
  • Must not be higher than the highest part of the existing roof
  • Must not be higher than four metres high

Conservatories built on the side of a property

  • Must not be wider than half the width of the original house
  • Must not have eaves higher than 3 metre if within 2 metre of a boundary

Conservatories built to the rear of a property

  • Must not extend more than 3 metres beyond the rear wall of an original attached house and not more than 4 metres for a detached house*
  • Must not have eaves higher than 3 metres if within 2 metres of a boundary


Serving Basingstoke, Southampton, Winchester, Portsmouth, Hampshire and the surrounding areas

With a showroom in Fareham and a showroom in Chichester, we're ideally placed to provide homeowners with valuable inspiration. Open 6 days a week, 10am-5pm, an array of beautiful products, a welcoming atmosphere and a professional, friendly and knowledgeable team await your arrival! Areas we serve include Basingstoke, Southampton, Winchester, Portsmouth & Hampshire.

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