Loft conversions: is your house actually suitable?

Before any design work, four things decide whether a loft conversion is straightforward, expensive, or not worth doing.

Head height comes first. Measure from the top of the ceiling joist to the underside of the ridge. Around 2.2 to 2.4 metres gives you comfortable options once the floor is built up and insulation is added. Less than that and you are looking at lowering ceilings below or altering the roof, both possible, both significant.

Roof structure matters next. Traditional cut roofs with purlins are usually easier to open up than modern trussed roofs, which need structural work to remove the webs and transfer loads. Trussed does not mean impossible; it means steelwork and engineering, and that shows in the price.

Then the staircase. It has to land somewhere sensible with adequate head height over the flight, and it has to come out of a space you can afford to lose. This is the point where many conversions are redesigned, the room in the loft is easy, the route to it is not.

Finally, fire safety. Adding a storey usually means fire doors to habitable rooms off the stair, a protected escape route, mains-linked alarms, and sometimes escape glazing. Budget for it from the start; it is not optional and it is not cosmetic.

If all four stack up, a conversion is one of the best value ways to add a bedroom and en-suite to a property, usually without touching the footprint of the garden.