How to add a mezzanine

Adding a mezzanine to create a split-level room is a great way to make any open-plan space more dynamic, in some cases it might also be a great way to get around an awkward room layout or use the space in a double-height room. Expert property renovator Michael Holmes offers his advice.

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A mezzanine storey is a great design solution for a room with a double height ceiling or loft space above. It provides additional valuable floor area, together with the impressive sense of volume created by a high ceiling.

Why would you install a mezzanine floor?

Typical situations that might suit a mezzanine are conversions, where the character of the building, be it a former barn or church, requires some double height space to remain on show. It may also be a good design solution in a listed building, where horizontal roof beams spanning the space are an obstacle to creating a full additional storey in the roofspace and can’t be altered.

On a smaller scale, a mezzanine can be an enlarged landing area overlooking the stairwell, or a gallery within the loft space above a bedroom, overlooking the room below, perhaps because the roof space is too limited for a loft conversion. In most situations you can use a mezzanine space at first floor level for any function, including a living area, sleeping platform, or a kitchen.

mezzanine level study in a power station apartment

Cantilevered stairs, by Glass UK, make a stylish feature and lead up to a mezzanine study overlooking the kitchen and living room in this converted power station

What permissions do you need for installing one?

Planning permission isn’t needed unless a house is listed, but all work must comply with the Building Regulations. If the work affects party wall structures, you must notify your neighbours (see the Party Wall Act in England & Wales). Leaseholders need permission from the freeholder for structural changes.

How to use the space

Mezzanines are a great way to maximise the footprint of a single storey home with a high ceiling. For example, a sleeping loft over a living space can create guest accommodation where a room is not available. Where this is done, you must not cover more than 50 per cent of the room it sits over.

Fire safety

At second floor level a mezzanine space cannot form a habitable room, such as a bedroom (unless the floor level is 4.5m or less, or above outdoor ground level and there is a fire escape compliant window) as it doesn’t comply with Building Regulations for fire safety as it’s open to the room below. If you do want a habitable space over a first floor room, you will need to treat it like you would a loft conversion and apply the same fire safety measures. Find out what this would entail in our loft conversion guide.

A second floor mezzanine must form a single space (no subdivision other than for storage, wardrobes etc) and the visible area of the room below should not be less than 50 per cent. Possible non-habitable uses for a second floor mezzanine can include an en suite bathroom (although this would need to be open to the room below), dressing room or storage.

a mezzanine bedroom with concrete ceiling in a loft style apartment

This converted aircraft parts factory features an enclosed mezzanine bedroom

Staircases and balustrades for a mezzanine

Access to a mezzanine level is via a conventional staircase — but if space is tight, options include a spiral staircase or, for a space that’s only used occasionally, a space saver staircase with hit and miss treads, or a fixed loft ladder with hand rails. You need to keep a maximum distance of 3m between the mezzanine stairs and the room below’s door, with a maximum of 7.5m from the furthest point of the mezzanine to the stairs.

An engineer will need to calculate the strength of the floor and any alterations required to the roof structure. The roof/ceiling will have to be insulated, and some form of balustrade will be needed where it overlooks the space below.

The balustrade and stairs are an important design feature. A glass balustrade and a simple staircase, or a spiral flight, work well in a modern space. The balustrade and stairs in a barn conversion should be minimal or sturdy and practical. For a traditional look, spindles, a handrail and a cast-iron spiral flight are a classic solution.