converting winders to quarter landing

S

sammoseley

Hi
I am in the process of working out whether my extension will be possible, currently have an existing staircase with 2 winders going off to the right where the existing landing is. It's a 30s semi.

I want to convert this to a quarter landing with stairs going off either side as I will knock through to the left as you go up the stairs.

I can't do much to make the existing stairs any steeper or put winders at the bottom, as this will break the 2m headroom rule (there is a wall about half way up the stairs which currently is less than 2m, the pink one in the pic, but I am guessing that's OK for building regs if I leave that part of the staircase alone - I could be wrong?!!)

My other concern is how the big existing joist that supports the ends of the landing joists will be supported as the new stairs up to the existing landing will effectively cut through it, can it be bolted to the newel post?

I know I've not described this very well but the pics may help hopefully, I'd really appreciate anyone's thoughts, whether I'm on the right lines or not, feel free to tell me I'm talking rubbish, etc

Cheers
Sam

 
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S

sammoseley

sorry meant to add, my plan is to cut into the existing landing as I will have to, in order to have 2 extra steps up into it from the quarter landing.
Hopefully it won't make the landing too narrow as there will still be 800m square area at the top of the stairs which I think is OK.

Cheers
Sam
 
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This is a very tricky one and tbh your options are very limited. A job I'm involved in at the moment has exactly the same configuaration as yours.
What we propose doing is to lift the existing straight flight vertically upwards by one riser in height. This will give a little more space to the 1st winder, making it trapezoidal in shape instead of triangular. We will continue this level through the thickness of the wall, and then have a couple more steps up to the (new) bedroom door.
Obviously, at the bottom, we will add one step, though this will bring it too near to the front door, so we propose angleing the tread to the left (ie like a single winder). At the same time, we will have to trim back the bulkhead the equivalent of 1 step length, to maintain the 1.9m headroom (ie this will be no worse than at present).
Putting a square quarter landing in, and then putting more steps to the right is not an easy option, as you will be cutting through the main trimmer along the landing. You may also have to push the bedroom doors further back, thus affecting those rooms. (the newel will be bolted to the joist, not the other way round, by the way).
Hope this makes sense.
 
S

sammoseley

Tony
Thanks for the reply, really useful. Yes what you say makes sense. However I can't cut the bulkhead back here without effectively losing a bedroom because there's already a narrow point where I'm knocking the box room through.
If I'm reading your post correctly, the main problem with doing a quarter landing is supporting one end of the landing trimmer, there must be some other way to do this (like a structural newel post going all the way down to the concrete floor below, maybe thats the wrong term but basically something vertical to support the end of it). I dont mind taking the ceiling down and propping it up etc to do that.
I'll re-check the measurements but don't think I can get away with doing what you say. PS is your method with the trapezoidal stair definitely OK with the BCO, I cant see why it wouldn't be
Thanks again
Sam
 
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You would have to support the cut trimmer with a post; something like 4" x 4" hollow steel. The important point is the base, as BC will probably want some suitable foundation pad, depending on load. If you are not sure about loadings, it may be best to speak to a SE.
You will also of course need to cut and trim the other joists to form an opening for your new steps.
Would it affect the doors to your rooms? This method was not an option on the job I described as the doors are too close to the top of the existing winders and so would have to be moved back. And no, we haven't had it approved yet, just hoping!............
 
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You would have to support the cut trimmer with a post; something like 4" x 4" hollow steel. The important point is the base, as BC will probably want some suitable foundation pad, depending on load. If you are not sure about loadings, it may be best to speak to a SE.
You will also of course need to cut and trim the other joists to form an opening for your new steps.
Would it affect the doors to your rooms? This method was not an option on the job I described as the doors are too close to the top of the existing winders and so would have to be moved back. And no, we haven't had it approved yet, just hoping!............
 
S

sammoseley

Don't think there is a problem with the doors, I still have 800 square at top of stairs, but depends what is meant by too close.
I'd hoped the post could just rest on the concrete floor below the ground floor joists, digging that out would be a pain.
Cheers again for the info,
Sam
 
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what is meant by too close.
At the top of the stairs, there has to be an unobstructed landing equal in depth to the width of the stairs. This means that the door facing you would have to be about 750-800mm away from the top edge of the stairs; on that score you should be OK.

The oversite concrete subfloor is an unknown quantiy. At the least, BC would ask for a decent spreader to spread the load over a reasonable area but, from my experience of inspectors, I think they will ask you to form a proper base. The Councils engineer may ask you for loading figures and this is why you would probably need an SE to do a scheme for you.
 
S

sammoseley

Tony
Thanks again for the advice, bearing in mind I will put a new trimmer in going from wall to wall, which will only be ~440mm back from the existing one (due to having 2x stairs eating into the existing landing), we are only talking about a 440mm "overhang" one end of which is unsupported so I think the whole thing will be doable, with a steel going down to the floor as you say.
Thanks again and good luck with yours
cheers
Sam
 
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Hi both,

Just stumbled across this thread and I am curious to see if either of you got the stair design to work out for the extension works? We've got the same staircase and are faced with the same dilemna, we cannot pull the stairs forward because of the bulk head and we cannot extend them due to the bedroom at the rear of the property.

I look forward to hearing how you got on with things and hope they'll be able to help us.
Thanks,
 
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Hi Guys, did any of you come up with the solution to this problem as I'm up against the same issue. Design Drawings and/or photos of solution would be helpful if possible? Many thanks
 
L

Leofric

the main problem with doing a quarter landing is supporting one end of the landing trimmer, there must be some other way to do this (like a structural newel post going all the way down to the concrete floor below,
Yes, a structural newel post going down to the ground floor - Tony 1851 has provided other information on this but the post could be 100 x 100mm timber.
 

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