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An open-plan layout can make your home feel lighter, more modern and more spacious and can add value. But the building regulations put limits on what you can build, requiring that your project has safe escape routes for occupants in the event of a fire. In this article we talk through some of the main options, tricks, tools and tips to ensure that your open plan layout project goes smoothly.

What is an open plan layout?

At its core, open plan simply means that your project has larger rooms with few or no internal dividing walls. The building regulations guidance may have a little or a lot to say about your open plan project, depending on exactly which rooms are to be combined into a single open space. The more open the layout, and the higher the property from ground level, the more restrictions you will encounter. So let’s get a bit more specific.

If your project has a kitchen and possibly other rooms open to the main escape route from the property, we will call this a type 3 open plan layout. For example this would normally be the case if your main staircase passes through a kitchen-diner.

If the kitchen is separate but the staircase or escape route passes through a habitable room, we’ll call this a type 2 open plan layout. For example this would be the case in many flats where bedrooms are accessed via the living room.

Finally, if you have a kitchen combined with another habitable room, but it’s not on the escape route from the property, i.e. there are no living or bedrooms off the open area, we’ll call that a type 1 open plan layout.

What sorts of open plan layouts are allowed?

The main law in this area is the building regulations, enforced by your Building Control inspector. If you have not yet started building, you have the right to choose between local authority building control, and private sector Approved Inspectors.

The Building Regulations are written in very general terms, but more detailed guidance is available: Approved Document B sets out how the regulations should normally be implemented. Although in theory you might be able to comply with the law without following the guidance, it’s essential to liaise very closely with your building control provider if you plan to do anything non-standard. All too often, projects can come unstuck because plans change during the build; layouts that Building Control deem inappropriate will not be signed off, leaving you with an unsafe and probably unsaleable property.

Let’s assume that your property has the correct complement of escape windows at first floor and below, and of fire doors. Here’s what the guidance will normally require:

  • Type 1 will normally be allowed.
  • In two-storey houses (or two plus basement) you’ll also be allowed type 2 or 3. However on the Isle of Man these layouts will need a fire suppression system.
  • A three-storey house (or three plus basement) with a type 2 layout is allowed in England and Wales, provided that you fit a suitable fire suppression system in the open area. You don’t normally need suppression in the upper storeys, but you will need a fire door between ground and first floors. Going from type 2 to type 3 is not always possible; sometimes it can be done based on a report from a fire engineer that justifies why your project is safe, and in most such cases an enhanced alarm system or some other fire safety measures are needed.
  • In houses of four storeys and above, you are likely to require either a second escape staircase from the upper floors, or a fire suppression system throughout most of the property, irrespective of your open plan aspirations. A type 1 layout will normally be allowed, and with a suppression system fitted throughout, your Building Control officer may be a little more flexible, but again you should expect to take some specialist advice relating to your specific project.
  • In flats no higher than first floor, you should usually be able to create type 2 or 3 layouts, though there may be some constraints on the location of the kitchen.
  • In flats above first floor, you are permitted to create open plan layouts if you install a fire suppression system. However the guidance is still being developed and you may need to appoint a Building Control Inspector familiar with the matter, or a Fire Engineer.
  • In some buildings, open plan flats must have a lobby or hallway between the front door and the open plan area. This lobby is a key safety feature for the building, and it’s best to assume that you will not be able to dispense with it, although this is sometimes permitted when supported by a fire engineer’s report, particularly if the character of the building is at stake.

Fire Suppression Systems

Traditionally, the only available fire suppression systems for the home were sprinkler systems, and these are still quite well suited to larger buildings and to new build projects where suppression is required throughout. Normally such systems are based on the British Standard BS 9251.

For some projects however, other suppression systems such as Automist may be an attractive option. Automist uses water mist to fight fires, acting as an alternative to sprinklers. This can be attractive when:

  • only a small proportion of the rooms need fire suppression
  • a premium on space makes it difficult to install a large tank
  • the water supply is somewhat limited
  • the project is a loft conversion, extension, retrofit or refurbishment.

Automist is covered by an LABC Registered Detail which currently allows type 2 layouts to be easily approved in three-storey houses in England and Wales, with additional layouts planned for the future. Your local Automist installer can provide advice on what is currently possible.

What about Scotland and Northern Ireland?

In Scotland and Northern Ireland the support for open plan in the guidance is unfortunately limited or non-existent. You also won’t be able to use private sector Building Control. You should expect to discuss your options with your local Building Control office at an early stage, and be ready to bring in a fire engineer if your Building Control officer agrees to this in principle.

Open Plan in Rented Properties

If you are plan to rent out your property, you need to go beyond the building regulations: you also need to comply with the laws applicable to landlords. In England and Wales, these are the Housing Act and the Fire Safety Order, which together have been written up as the LACoRS guidance. These regulations apply even if you aren’t changing the layout, and you should consult your local authority’s private sector housing team as to what is expected of you. In broad terms, the LACoRS guide does allow most of the types of open plan layouts that are permitted by the building regulations, except where a house has been subdivided into bedsits where residents lead separate lives. As a landlord you must comply with the law whether or not your property is an HMO (house in multiple occupation) – and you could go to jail if someone is seriously injured or dies in your property and you have failed to do so.

Getting Going

Open plan layouts can make a huge difference to a property and can be relatively straightforward to achieve with the right partners in place.

For any sort of unusual layout – for example a type 3 layout with rooms above first floor, or if your property includes higher floors in a building of four or more storeys, we recommend beginning with discussions with your building control provider to discuss the types of layouts that they can approve. For the more typical cases, an architect or loft conversion specialist with detailed knowledge of the field may be your best place to begin. And for cases that will need fire suppression, a specialist installer should be able to help you explore the types of layout that are commonly approved.

Finally, and we can’t emphasise this too strongly, you should discuss your plans in detail with Building Control before you build!

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