Minimum width of an understair WC

[Adsibob]

We are having new staircase built for our renovation. Architect has allowed a width of 900mm for the staircase and thought the WC underneath might be 86cm wide plus 13cm for the stud wall such that the wall would stick out by 9cm. I don’t think that would look good at all. Surely the external surface of the WC wall should be in line with the external surface of the staircase stringer, or the stringer should stand proud. If the WC wall protrudes beyond the staircase, I think it will look odd.
here is a picture:

How wide would you make:

- the staircase

 - the internal width of the WC room; and

- the stud wall of the WC room?

 

 

[Temp]

Just measured our stairs..  The width of our treads is 900mm between the stringers but overall the staircase is around 1m wide including the wall stringer one side and the newel posts on the other.

 

If your WC wasn't under the stairs I would recommend 1m internal width. However that would make your stairs about 1.1m wide which is quite big, perhaps ok if you have space.

 

I reckon 80cm internal width/90cm stairs is the smallest I would want to go for the WC. 

 

So I reckon a reasonable compromise would be 90mm internal width and roughly 1m wide stairs. Personally I think it looks better if the stringer stands outside the wall like this. 

 

 

 

 Source of image:  http://www.at-carpentry.co.uk/worcestershire-oak-staircase-renovation/

 

 

 

[Adsibob]

18 hours ago, Temp said:

Personally I think it looks better if the stringer stands outside the wall like this.

I couldn’t agree with you more. Hence my shock when architect thought it would look fine for the wall under the stringer to stand outside instead!

 

we aren’t having a newel post (having a wreathed handrail that continues into the floor instead) so might be able to go to 94 internal width of staircase, plus 2 X 42mm for width of each stringer, would make 102.4cm, which would allow about 88cm, if stringer is to stand a couple of cm proud for internal depth of space for WC. 

[Big Jimbo]

I think from memory that a staircase of 1000mm or more needs a handrail on both side ?

[syne]

Could you afford the space to budge the stairs over above the wall below to keep it looking 'traditional' and then bulk the wall out on the stairs themselves?