Constructing a basic staircase for a loft conversion follows 11 stages:

Checking building plans

Stripping back to bare wood the area that will become the landing

Building a load beaming timber-frame wall (stud-partition) from floor to ceiling. This supports the sawn attic joists and ceiling

Check and re-route any electrical cables/wiring or plumbing in the loft that obstruct the opening into the stairwell and route to where they will be required

Accurately measure, mark and cut the opening in the loft. Sawing through ceiling and now supported joists and disposing of waste

Install the diagonal 'strings', these form the sides of the staircase and carry the load of the stairs

Make the steps (treads and risers), measure and mark entire string, glue and tension screwed wedges (noggins) where treads/goings (horizontal) and risers (vertical) sit, joined at the overlap by a rebated groove. Minimum depth of tread/going is 220mm; Maximum rise not more than 220mm

Build in any turns, installing a newel post (vertical post from the ceiling) firmly bolting it to the attic joists. Constructing kite-winder (up and round) or quarter turn landing (flat)

Fitting handrail and balusters to agreed designs

Around the top of the flight of stairs, build a handrail or partition wall and design elements depending on room use and designs.

Plaster and skim the partition walls and decorate.