Mezzanine/loft play area

[Badgerlovesmashedpotatoes]

Has anyone made a mezzanine into their loft from the box room?
Just wondering how feasible it was/whether it looks good/how expensive it was?
DS (4) is currently in the box room but has little floor space for playing. We can't have a raised bed as it would obstruct the loft hatch. We may do a loft conversion eventually but wondering if this sort of part conversion would work / be cheap enough in the interim. Ceilings are high but not high enough for a proper mezzanine. Been looking online but can't see much thats similar to what I am thinking of.
Does anyone have any experience (or other suggestions?)

I know a couple of people with very basic conversions, just staircase, floor reinforcement, insulation/plastering, velux windows but no dormer and no changes to the roof profile. Depending on the shape of the building this might be enough to give you a decent sized room for a young child. It's not a good idea to do any less than this. The joists in the loft aren't designed to support a floor, so a proper conversion would have (expensive) steels right across the width of the house and the new floor suspended on those. You also need fire doors throughout the house when you add a third floor, I think this also includes a fire door closing off the loft, but not sure how this works with mezzanines. A house near us had a bad fire and the insurance company did not pay out because they had an 'unofficial' loft conversion and no fire doors. It might also make it hard to sell your house in future if it's not a 'proper' loft room.

Personally I'd get some quotes for a very minimal loft conversion. Speak to a few builders who have worked in your area to get an idea of prices and what would be the minimum you could get done that would comply with building regs and maybe they will be able to give you some ideas for a solution that is affordable.