3rd storey open plan loft conversion & fire suppression

If you’re planning on adding a 3rd storey then you’ll also need to install fire suppression if you want an open plan arrangement.

Fire safety isn’t just important; it’s an essential building regulations requirement. Follow our handy guide to find out about the risks, the regulations and how to stay safe. There are several different types of loft conversion according to design and how much potential new space is being added. They range from the relatively simple addition of roof lights and Dormer windows, to hip to gable, gable to gable and Mansard conversions. Whatever type you choose, it’s worth noting that you’ll also require a minimum practical ceiling height of 1.9m, though you can incorporate areas with sloping ceilings usable for seating and storage. When it comes to the stairs, building regulations require 1.9m of clear headroom above, at the centre of the flight, and 1.8m at the edges, to allow for sloping roofs.

Loft conversion

Loft conversion

Converting your loft is one of the most cost effective ways to add extra living space to your home and it can add value, but while you probably won’t need planning permission, your project will require building regulations approval. These regulations will ensure that the structural strength of the new floor is sufficient, that the stability of the structure (including the existing roof) is not endangered, that there are safely designed stairs to the new floor, that there is reasonable sound insulation between the conversion and the rooms below, and that there is safe escape from fire.

When it comes to fire safety, you need to provide an escape route as well as additional fire protection throughout the rest of the house.

The following four conditions aren’t law, but they form part of a national guide and a project that complies with them will pass building regulations more easily than ones that don’t.

  • Where your loft conversion forms a third storey, it needs to be separated from the rest of the house, and the walls, floors and doors need to be given what’s referred to as half-hour fire protection. This can be achieved using two layers of plasterboard and installing fire doors.
  • The usual means of escape in the event of a fire is the main staircase, which must lead directly to an external door, so this also needs to be enclosed and given half-hour fire protection. This means all doors to habitable rooms need to be fire doors. Mains powered, interlinked smoke alarms must also be added within the stairway of each floor of the house.
  • If the staircase ends in an open plan room, this area needs to be fitted with a fire suppression sprinkler system as well as a fire door separating the ground floor from the first floor. In the event of a fire, escape can be made via an appropriate first floor window.
  • Loft conversions to bungalows don’t need an enclosed staircase if there’s an appropriate fire escape window in the habitable loft rooms.

With guidance from a building control officer or appropriate advice from a Fire Engineer, you may be able to make additional changes. See Approved Document B for more information.

Fire suppression is key to survival, but compartmentation isn’t realistic in contemporary open plan layouts like loft conversions, especially if there are dummy walls. However, UK regulations allow the use of fire suppression options like sprinklers to compensate for this.

Sprinklers were originally designed for large business spaces and are considerably expensive. In UK homes the project is a lot smaller, and low mains pressure, high flow requirements mean substantial costs to the homeowner in the form of pumps, tanks and upgrades. Now there’s a convenient and cost effective alternative in total compartment application systems (retrofittable sprinkler alternatives).

Fitting the right fire suppression into your home doesn’t have to significantly increase the cost of your loft conversion, it can in fact give you peace of mind your home is safe.