Help / suggestions with design

[profchris]

Ah no, just looked at the first picture again and I see it's 150 mm wide where it joins. But I'm still scared!

 

[MikeG.]

........ My mental arithmetic tells me that each step is only 40 mm wide where it joins the pole..........

Building Regs require a minimum going of 50mm. The leading edge of an open step must overhang the rear edge of of the step below by 16mm minimum, so adding your 40mm calculation to 16mm suggests a minimum going (tread width) of 56mm. Another regulation that's important here is that there shouldn't be any opening in the stair exceeding 100mm, so there will need to be a downstand under each tread such that a gap which would otherwise have been of the order of 195mm is down to 100mm. This is effectively a structural rib=, strengthening each step.

Having said that, if the building inspector can be persuaded that there will never be access for children in any circumstances, then the 100mm rule need not apply. I imagine that would mean a lockable hatch, at the very least. In fact, because the handrail rules will be broken I suspect that a locked hatch is going to be an absolute requirement anyway.

Ah no, just looked at the first picture again and I see it's 150 mm wide where it joins. But I'm still scared!

Reading this first could have saved me some typing. :lol: