Almost a loft conversion?

I'm thinking of increasing the space in my house. One idea I had was to remove the ceiling in the main front bedroom making the roof space a part of that room, then building a 'platform' level above part of the main front bedroom and extending back over the bedroom at the back of the house. This would make a large split level space, but essentially one room. What building regulations would apply? Is this a loft conversion re fire regulations etc. What kind of staircase would be required? What about any requirements thoughout the rest of the house, which already has a basement level. Any help on building regs and problems I may encounter would be useful. Anyone done anything similar? I know I need to speak to local building officer etc. But would like to know if the idea is a non-starter. Many Thanks. Paul

All of them :-)

You will probably need to strengthen the floor over the back bedroom and as you will not be able to use joists running front-back of the house this may require more inventive steelwork.

You may need to add more daylight and ventilation, perhaps by Velux windows in the sloping part of the front ceiling, and be aware that heat from the main room will rise up to the mezzanine so you might need to give the bedroom radiators some more oomph.

It is a loft conversion as regards insulation etc. However, AIUI you would not be creating an extra storey and providing the mezzanine space is integral to the main bedroom would not require additional fire precautions in the rest of the house. This obvoiusly must be confirmed with BCO.

I think you have some leeway on that as regards width and pitch as it's only for reaching a mezzanine and would not be treated as continuous of the existing staircase. However as it's a bedroom and people might be sleepy (especially if going up to an en-suite loo up there), I wouldn't do anything too radical.

And is therefore already 3 storeys? I don't know if the BCO would thus require the fire regs to apply to the new space, or would accept the existing on the 'not making worse' principle.

I would strongly suggest that you do have interlinked smoke detectors anyway, and if the door to the main bedroom (and the ceiling below it and the conversion space) is 30 min fire rated and you have first floor escape-from-able windows on the front bedroom you have I think a strong argument for saying that means of escape are adequate.

I think the mezzanine idea is very much a starter and a good way of creating some additional space where a full loft conversion isn't possible and a self-contained extra room is not required.

However, it isn't going to add the value to the house than an extra bedroom ie full conversion would, it might end up not costing much less than a full convcersion, and the resulting room might be a rather odd shape which might not appeal to everyone.

Owain