Cellar stairs construction

[hamjam]

I’ve had a cellar built under my new extension and need to get some stairs set up. The access is via a trapdoor (approx 1200 long and 800 wide) in kitchen floor and currently I’ve just got a ladder down to the floor of the cellar. The overall height from cellar floor to the underside of the floorboards is approx 2800.

I don’t think I’ve got the room to set up a flight of stairs which fully complies with the BCA rules for tread and riser dimensions as this wouldn’t give enough head height. Therefore I’d be looking at something more like a loft ladder which I’d hopefully be able to get past the building surveyor.

Given that it has to be simple (and cheap), I’m looking at a getting a couple of pine stringers and using the same material for the treads (it would be open treads). So the questions:

Any suggestions on what thickness timber for the stringers and the treads?
Can I just use steel brackets to hold the treads to the stringers? For the brackets I was thinking of getting some angle iron and cutting to lengths
I’ve seen a lot of similar stairs with steel rods running under the treads holding the stringers together – this could be as well as or instead of the brackets- are these necessary?
Would I need to make a rebate in the stringers to slide the treads into or would the bracket be sufficient?thanks
hJ

[hamjam]

Anyone got any thoughts on this? I'm keen to get this project started.

Thanks
hJ

[SilentButDeadly]

Any suggestions on what thickness timber for the stringers and the treads? stringer = 150x50 F7 OB hardwood, treads = same - make handrails running down the stringer using 1/2 gal pipe
Can I just use steel brackets to hold the treads to the stringers? For the brackets I was thinking of getting some angle iron and cutting to lengths
Yes - angle is fine - 50x50x3 gal
I’ve seen a lot of similar stairs with steel rods running under the treads holding the stringers together – this could be as well as or instead of the brackets- are these necessary? Yes - it stiffens the structure. You can use the angle - run it in a triangular cross behind the treads
Would I need to make a rebate in the stringers to slide the treads into or would the bracket be sufficient?
the latter is fine

[hamjam]

Thanks very much.

hJ