Stairs opening trims

A message for Amber. We have a Two storey town house extension requiring single flight Stair Block, we can trim the opening on one side with shorter Floor Blocks but the adjacent external side wall will not have the Floor Blocks. How do we do we make up for this missing thickness? Do you envisage trimming beams? Also intrigued to how the Stair Block are fixed to the upper Floor Block? Help please with some details? Graham Osborne, Australia

Hi Graham,

Thanks for your question.

The stair will need to be supported by (and fixed-into) a supporting wall on both sides.
If I’m visualising your situation correctly, another structural element, i.e. potentially timber trimmers, could be used to fill the gap to one side and join the stair to the existing side wall, but this detail would need reviewing by a local qualified designer to check the element is strong enough to support the load from the stair.

The stair element itself should be viewed like any typical timber stair.

I’ve attached some images of a recent project here in the UK which used a WikiHouse stair. Some of the design details might be helpful as a guide for your project.

Thanks Amber, for your promptness, we will try for straight flight but presently waiting on DA approval before sending you any sketches etc.
Graham Osborne