Loft conversion

Building regulations approval is required to convert a loft or attic into a liveable space.

This section provides guidance for making alterations to the loft space of an existing house which is no more than two storeys high. Requirements for alterations to an apartment or other dwellings like maisonettes, or houses over three storeys, will be similar but may be more extensive and possibly extend to other parts of the building.

The regulations will be applied to ensure, for example:

• the structural strength of the new floor is sufficient
• the stability of the structure (including the existing roof) is not endangered
• safe escape from fire
• safely designed stairs to the new floor
• reasonable sound insulation between the conversion and the rooms below.

You may wish to make these alterations to enhance the storage facilities available or to increase the living space of the home. If you plan to make the loft space more accessible or more habitable by, for example, installing a stair to it and improving it by boarding it out and lining the walls/rafters etc., more extensive work is likely to be required and the Building Regulations are likely to apply.

It is recommended that you contact Building Control to discuss your proposal and for further advice and you must also find out whether work you intend to carry out falls within The Party Wall etc. Act 1996.

Boarding-out for storage

In most homes, the existing timber joists that form the "floor" of the loft space ( i.e. the ceiling of the rooms below) will not have been designed to support a significant weight (known as "load"). The joists tie the pitched members of the roof together to prevent them spreading and support the ceiling lining of the rooms below.

An excessive additional load, for example from storage, may mean that the joists are loaded beyond their design capacity. If you decide to lay flooring boards over the existing joists in the loft space, then this may require a Building Regulations Application to Building Control. Your local Building Control body will be able to advise you on this issue.

Creating a liveable space

If you decide to create a liveable space (a 'liveable space' is where you intend to use the room as a normal part of your house, including spare bedrooms which may be used infrequently) in an existing loft space of a home it is likely to require a range of alterations.

Many of these could have an adverse impact on the building and its occupants if they are not properly thought out, planned and undertaken in accordance with the requirements of the legislation.

Further information

A planning consultant may help with the smooth running of your loft conversion project. To find an accurate consultancy quote, explore Studio Charrette's calculators¹. Further information

The following common work sections give an indication of several other elements normally required to satisfy the requirements of the Regulations when converting a loft:

• Doors and windows²
• Drainage³
• Electrics⁴
• External walls⁵
• Internal walls⁶
• Kitchens and Bathrooms⁷
• Roofs⁸

1. https://www.planningportal.co.uk/permission/home-improvement/planning-consultancy-calculator
2. https://www.planningportal.co.uk/permission/common-projects/doors-and-windows/building-regulations
3. https://www.planningportal.co.uk/permission/common-projects/drains-and-sewers/building-regulations
4. https://www.planningportal.co.uk/permission/common-projects/electrics/building-regulations-general-information
5. https://www.planningportal.co.uk/permission/common-projects/external-walls/building-regulations
6. https://www.planningportal.co.uk/permission/common-projects/internal-walls/what-building-regulations-apply-to-internal-walls
7. https://www.planningportal.co.uk/permission/common-projects/kitchens-and-bathrooms/is-building-regulations-approval-needed-for-work-to-a-kitchen-or-bathroom
8. https://www.planningportal.co.uk/permission/common-projects/roof/building-regulations-work-to-an-existing-roof