> We would like to replace our two collapsing, winding staircases with one
>> (gonna block up the other) spiral staircase, in our late 1700's
>> farm-workers cottage.
>>
>> The stairwell is very small, 1700mm x 94mm, but this would seem just
>> big enough to fit in a 11 tread spiral, with 200mm treads.
Trying to work out if you mean 1700 x 940 or 1700 x ?94
200mm rise per tread? So a total rise of 2200mm By winding do you mean a 180deg turn or a +90 -90deg type?
Not keen on spirals as a sole means of access, although it would be possible to fit one made of standard stair joinery i.e. central full height newel with treads extending to the wall. Old winding 18thC stairs sound charming, modern spirals do not. Please be more detailed, it's an interesting problem.
Sorry, my mistake - I meant 1700mm x 940mm, and yes our ceilings are 2200mm.
The existing staircases do a complete 180' turn, with treads that go to the wall (ie, not circular when viewed in plan).
The 940mm dimension is between the end wall of the house and the landing. It cannot be widened because the landing is needed there to access the bathroom and a bedroom.
There really is no chance of a full staircase, so we'll have to do something in this space! I suspect we can't get something off the shelf and will have to build something in-situ; I was more concerned about having to have this as a single staircase.
I believe there would be nothing to stop you 'rennovating' one of the existing stairs even if this meant renewing every single piece of timber if the exisiting condition is of concern. Also there is no problem if this is the only access between the two levels. Although an alternative stair fitted as part of conversion work _should_ comply with the regs. Very few stairs are 'off the shelf' anyway unless you want a straight 12 flight. The rise will be from floor to floor so I guess yours will be closer to
2400mm.
From Powell-Smith & Billington's Building Regs Explained "Generally spiral stairs designed in accordance with BS5395 Part 2:1984 will satisfy AD K. It is permissible to provide stairs with lesser goings for conversion work if space is limited, but the stair should only serve one habitable room and perhaps a bathroom. The degree of variation from the norm is however unspecified." I've considered and rejected a spiral in a previous project in similar circumstances. I assume you would place the column closer to the landing to gain a passage width greater than 450mm, but still the headroom at the base may cause concern. If your spiral was of a 270deg 4 treads per 90 type, the headroom at tread three/four would be a problem.
You may be concerned with maintaining a satisfactory means of escape throughout the property. A single stair serving a two storey property is deemed adequate. You also have the backup option of egress through an upper window opening of sufficient size.
It seems the only way to fit a standard 42degree timber stair would be to extend the 1700 length at the ground floor. A three flight extension to the
90deg entry within the exisiting base would most likely compromise the
2000mm headroom rule, whereas extending the length of the flight would not. I believe an off the shelf 1400mm spiral would also create the same headroom problem.
No easy answers, but you knew that, I hope you can retain the existing steep staircase.
From the chaotic regions of the Cryptosphere, Succorso wrote on Sun, 03 Aug 2003 09:45:37 +0100:
No problem with using a spiral as the main stair (subject to the correct goings, etc.); use BS5395 Part 2. The minimum diameter for a stair serving more than one room given in this BS is 1800mm, but speak to Building Control to see if they would permit a narrower stair- possible if it is replacing a non-compliant one.
The other issue about removing a stair is making sure that you are not adversely affecting the means of escape. With only one stair you will probably have to make sure that all the first floor (bed)rooms have windows large enough to escape through.
You also will probably need Listed Building consent.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.