Can You Convert Your Loft?

The main feature that will be decisive whether or not you can convert your loft is the available head height. The head height should be no less than 2.4 meters; this measurement needs to be taken from the loft floor to the top of the ceiling joist. If the head height is less than 2.4 meters there are a couple of options. The first option would be to remove part or all of the original roof and rebuild it higher to gain the extra head height. This is generally not the best option due to the high cost and gaining planning permission. The second option is to pinch some height from the rooms below and lower the ceiling height. In the rooms below there needs to be a height of at least 2.4 metres.

Planning permission is not normally required for loft conversions; however, permission is required where you intend to extend or alter the roof space to exceed specified limits and conditions. The limits and conditions are:

• A volume allowance of 40 cubic metres additional roof space for terraced houses.
• A volume allowance of 50 cubic metres additional roof space for detached and semi-detached houses.
• No extension beyond the plane of the existing roof slope of the principal elevation that fronts the highway.
• No extension to be higher than the highest part of the roof.
• Materials to be similar in appearance to the existing house.
• No verandas, balconies or raised platforms.
• Side-facing windows to be obscure-glazed; any opening to be 1.7m above the floor.
• Roof extensions not to be permitted development in conservation areas or article 4 land.
• Roof extensions, apart from hip to gable ones, to be set back, as far as practicable, at least 20cm from the original eaves.
• The roof enlargement cannot overhang the outer face of the wall of the original house.

Please note: the permitted development allowances described here apply to houses not flats, maisonettes or other buildings. View guidance on flats and maisonettes here.
To further understand planning requirements and whether you need it or not visit the planning portal.

Since the end of 2008, changes to permitted development laws have made it easier than ever to convert the loft and you shouldn’t need planning permission. However there are still a few hoops to jump through before you can. Your extension must still comply with Buildings Regulations and this means that you will need professional input in the planning and design stages. The floor may need reinforcing if it has not been designed to take heavier loads and the loft must also be sufficiently insulated from sound coming from below.

Fire safety is a crucial aspect of the regulations; the new storey must be isolated from the house by half an hour’s worth of fire resistance, which almost certainly means installing fire doors. Your existing doors can be upgraded to provide sufficient protection (useful if you have period features). In addition, any method of escape must be via a corridor, which means that your loft stairs can’t lead straight down into an open-plan area.
Last but definitely not least, if any work affects the wall, floor or ceiling of the adjoining property, you will need written consent from your neighbours under the Party Wall Act with relevant notices being served.

What you will need in order to get you project started:

• Full plans and drawings to gain approval whether it be for full planning permission or under permitted development. The plans are also key in ensuring your
design will actually work within the space available.
• You will need further plans that are compliant with building regulations.
• Relevant party wall procedures followed set out under the Party Wall etc Act 1996.

The main question everyone has after all of this is how much does a loft conversion cost from start to finish? Every conversion is bespoke and costs vary from project to project.

If you are thinking about converting your loft or have any further questions please feel free to contact us and one of our architects would be more than happy to answer any questions you may have.

Best Regards


April 2015

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