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Loft conversions

Loft conversions are a popular way to increase space in your home, but they can be more complicated to build than extensions and more restrictions apply to them.

Do I need building regulations approval?

Yes, if the room will be lived in. You should make a Full Plans or Building Notice application, and a Building Control Surveyor must inspect the work.

If you’re going to use the loft for storage you might still need approval, as many properties’ loft floors won’t be strong enough to support additional weight. 

Planning permission

Many loft conversions don’t need planning permission as they are within your development rights. But if you want to extend or alter the roof space and it exceeds specified limits and conditions you will need permission.

What regulations apply?

The main things to take into account in loft conversions are:

  • structural stability
  • fire escapes
  • stairways  

Is the existing structure strong enough?  

Existing houses which are in good structural condition are generally capable of accepting the additional loads from loft conversions without any further strengthening works being necessary. Older properties should be checked for structural defects which may need to be addressed before a loft conversion can take place.

Most loft conversions need steel beams to support the new floor joists and roof. The structural design of a loft conversion is often more complicated than an extension. So you will probably need a professional (for example, a chartered structural engineer) to do the calculations for you.

Do I need fire doors?

Lofts are a long way above the ground, so you should consider fire escape routes. If you have a two-storey house, you will usually need to replace the existing doors around the whole staircase (except those to low risk rooms like bathrooms and cloakrooms) with fire-resisting doors, to make a fully-protected path to the ground-floor exit.

The new room(s) in the loft also need to be provided with fire-resisting doors. Any glazing in the walls enclosing the stairs will need to be replaced with fire-resisting glass. It is sometimes possible to retain existing period doors (providing they are reasonably substantial and in good condition) by upgrading them, or putting in compensatory measures (contact Building Control for further details).

If you have an open-plan layout at ground floor level, you can put in walls to separate your stairs from any rooms, and link them to an escape route to the outside. There may also be options for using domestic sprinkler or water mist systems.

Until April 2007, all doors to habitable rooms off the stairwell had to be provided with self-closers. You no longer need to do this, but everyone in the household will need to be much more aware about keeping doors protecting your escape route closed, especially at night.

Do I need smoke detectors?

You must fit mains-powered interlinked smoke detectors at each level in the hall and on each landing. All smoke alarms must have a standby power supply (e.g. battery backup)

Do I need stairs?

You must put in fixed stairs to give safe access to and from the new room. The regulations cover things like staircase steepness, headroom, step sizes and handrails. The stairs should meet the current regulations whenever possible, but some variations may be considered if there is insufficient space for this to be achieved.

How do I make an application?

The quickest way to apply is directly through the Planning Portal website. Alternatively, you can complete an application form and return it to us via email, ensuring to attach copies of your building plans, structural engineering designs and site location plans (where appropriate). Payment can be made directly through the Royal Borough of Kingston Upon Thames website. Our charges are among the most competitive in London and start at just £665.00 inclusive of VAT for a simple extension. When the work starts or you need to schedule a site inspection, you can book this on-line through the Royal Borough of Kingston Upon Thames website. If you prefer, you can always contact us on 020 8547 5002.

Last Modified: 14/03/2022 14:27:07