Loft Conversions



A loft conversion can add a significant amount of money  – up to 20% – to the value of a property. Many families choose to convert their loft area as a means of obtaining more space without having to endure the costly and stressful process of moving home. Work taking place in the loft can also be less disruptive than, say, a major extension to an existing living space.

Be careful not to outgrow your road. If you invest too much and extend too far you’re unlikely to see a return on your investment.



You’ll want to start by assessing whether your roof space is suitable for conversion. Most are, but there are three main things to check:

  • Internal height. Measure from the top of the ceiling joist to underneath the ridgeboard in the apex. It needs to measure 2,500mm to suitably convert.

  • Roof pitch. Measure the angle of the roof. The higher the pitch angle, the higher the central head height is likely to be.

  • Footprint. As a minimum rule of thumb, internal rules should measure 5,500mm side to side, inclusive of chimney, and 7,500mm front to back.


For most loft conversions, planning permission is not required. That's because they generally fall under your permitted development rights.

That said, you will need to get planning permission if your plans exceed certain limits and conditions, such as extending or altering the roof space beyond its current limits. You'll also have to follow strict building regulations, which are in place to ensure that building work is done safely. In this article, we'll discuss both of these important topics.


The rules of permitted development outline the work that can be carried out without the need to seek planning permission. The limits and conditions of how permitted development applies to loft conversions are outlined in Schedule 2, Part 1, Class B of The Town and Country Planning (General Permitted Development) (England) Order 2015.

To find out whether or not you need planning permission, it’s always wise to speak to a professional to confirm it for you. That said, a loft conversion falls under permitted development and does not require planning permission as long as it meets the following conditions:

  • The new loft space won’t be larger than 40 cubic metres for terraced houses and 50 cubic metres for detached and semi-detached houses.

  • The loft conversion doesn’t extend beyond the plane of the existing roof slope at the front of the house (principle elevation).

  • The loft conversion does not extend higher than the highest part of the existing roof.

  • The loft conversion does not include any verandas, balconies, or raised platforms.

  • The loft conversion is made using materials that are similar in appearance to the rest of the house.

  • Any side-facing windows must be obscure-glazed (to stop people seeing in and out).

  • Any side facing windows must be at least 1.7m above the ground.

  • Your home is not located in certain designated areas, including national parks, Areas of Outstanding Natural Beauty, conservation areas, and World Heritage Sites.

  • A roof extension, with the exception of hip-to-gable extensions, must be set back at least 20cm from the original eaves.

  • A roof extension must not overhang the outer wall of the original house.

For any alterations that exceed the limits and conditions listed above, you will need to apply for planning permission from your local authority. Fortunately, this can now all be done online, and you can apply to every local authority in England via the planning portal

For further information on permitted development, please read the government's technical guidance on permitted development rights for householders.

Please note: The limits and conditions for loft conversion permitted development above only apply to houses, and planning permission will have to be sought if you live in any of the following:

  • Flats

  • Maisonettes

  • Converted houses

  • Houses created through the permitted development right to change use

  • Other non-dwelling buildings

  • Homes in areas where there may be a planning condition or other restriction that limits permitted development rights

Roofing Specialists - Building - Carpentry

07887 937905

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