Fitting the centre post was simple. I first fitted an off cut of the 100 x 100mm timber into the Floor with half joints in to three joists to spread the load. The notches in the joists are only 700mm from the wall and the joints are tight so I wasn't worried about weakening the floor. The bottom of the centre column is bolted on to it. The column at the attic floor level is mortice and tenoned to the end of a floor joist I had left sticking out.

I wish I could find the pictures I had taken at this stage, but thats the down side of digital pictures. I think the camera was borrowed and the card wiped before I'd transferred them.

The next pictures should give an idea of the construction methods used. I screwed stringers on to each of the two walls, after some final measuring. Then made the the side/stringer that goes over the existing stairs. This fits on to the other vertical post I put up. Followed by the last two bits of stringer. All of the stringer are flat, no recess or grooves to take the risers or treads. All these I cut from 18mm Birch Ply, its good to cut with a smooth edge, no voids and should finish well for painting.

The risers and treads are cut from the same ply, 3 off 8x4 sheet in total. The risers needed cutting at an Angle to meet the stringers and the inside ends fitted in the slots of the column. On the wall stringers I shaped brackets out of ply and screwd and Glued them on to Suit. The other risers are screwed and glued directly on the outer stringers.

The steps are individually cut to fit. Almost every one tricky to mark out because of the number of angles. But seeing it go up one step at time kept me going and I eventually got to the top.

If any one wants to know more about how I built these, please leave a comment. It took me ages to figure out the construction method to suit my skills, a minimum of tools and materials availability.