Stair build

[LBCarpentry]

Hello gents (and possibly ladies),

Got a straight flight of oak stairs to build soon and looking for some pointers as i haven't set a staircase out before.

I know the rise is 2600mm and the available Going is no issue.
I'm basically trying to work out if there are upper and lower limits to the size of riser and treads. Is there an ideal standard? or a ratio between the two?

I intend to have 30mm solid treads and 12mm oak veneered MDF for the risers.

I do know how to physically construct them once set out. but its the setting out I'm not 100% sure about....

Thanks in advance!

 

[Trevanion]

If you're conforming to building regulations and depending on the type of stair there is a maximum rise and a minimum going, for a private dwelling this is 220mm maximum rise and 220mm minimum going. I find a comfortable going is about 260mm or so without feeling too cramped or too long.


What is the construction? Trenched, Cut String, Etc...? 30mm treads would be a bit excessive in my opinion for a trenched staircase and would look out of proportion, not to mention bleeding heavy to lift the stairs into place!

 

[LBCarpentry]

If you're conforming to building regulations and depending on the type of stair there is a maximum rise and a minimum going, for a private dwelling this is 220mm maximum rise and 220mm minimum going. I find a comfortable going is about 260mm or so without feeling too cramped or too long.


What is the construction? Trenched, Cut String, Etc...? 30mm treads would be a bit excessive in my opinion for a trenched staircase and would look out of proportion, not to mention bleeding heavy to lift the stairs into place!

Thanks for the input, a great help.
There's no issue with me making 25mm treads, I just wanted it to not look standard or off the shelf as usual.

It is a trenched staircase in Oak
275/300mm x 32mm stringers
approx 900mm wide

 

[Trevanion]

There's no issue with me making 25mm treads, I just wanted it to not look standard or off the shelf as usual.

An off the shelf staircase usually has 19mm treads, they flop about quite a bit! :lol:

It is a trenched staircase in Oak
275/300mm x 32mm stringers
approx 900mm wide

I like to opt for 42mm strings, reason is that I can comfortably take a 15mm trench out of it with plenty of meat left to make it a totally dead staircase with no flex, a big bonus is you can take the router to the other side of the string to remove 15mm off each side for your tenons with leaves 12mm to go into the newels.

Most of my strings end up being about 210mm, which is what I'll get out of a 9x2 softwood plank amply. If in oak I usually can push it to 250mm if I've got the sizes but there really isn't much need to do so.

900mm wide is quite a width, perhaps 30mm treads wouldn't look too ridiculous.

 

[LBCarpentry]

There's no issue with me making 25mm treads, I just wanted it to not look standard or off the shelf as usual.

An off the shelf staircase usually has 19mm treads, they flop about quite a bit! :lol:

It is a trenched staircase in Oak
275/300mm x 32mm stringers
approx 900mm wide

I like to opt for 42mm strings, reason is that I can comfortably take a 15mm trench out of it with plenty of meat left to make it a totally dead staircase with no flex, a big bonus is you can take the router to the other side of the string to remove 15mm off each side for your tenons with leaves 12mm to go into the newels.

Most of my strings end up being about 210mm, which is what I'll get out of a 9x2 softwood plank amply. If in oak I usually can push it to 250mm if I've got the sizes but there really isn't much need to do so.

900mm wide is quite a width, perhaps 30mm treads wouldn't look too ridiculous.

900 is wide, its what the current staircase is. I may try and sneak it down to 800mm wide just to save a bit of weight...
Thank you very much for the input. That has almost answered all of my queries. My usual George Ellis source was starting to make my head spin and was becoming, in true Ellis style, quite elaborate but very proper.

 

[Doug71]

part K of the building regs covers stairs and is quite useful.

To add to what Trevanion said the maximum pitch is 42 degrees so you can't use the maximum rise with the minimum going.

There is a recommended ratio which is that the sum of twice the rise plus the going (2R+G) should be between 550mm and 700mm

 

[Trevanion]

If you're into books, A Treatise on Stairbuilding and Handrailing by W&A Mowat and A Simplified Guide to Custom Stairbuilding and Tangent Handrailing by George R diCristina are worth picking up. You almost need a shot of adrenaline before reading to be able to understand some of the complex stuff in DiCristina's book :lol:

I don't really know of any modern books that comprehensively cover the subject in a truly modern time with all the regulations and stipulations, but I haven't particularly been looking for them.

 

[MikeG.]

........I know the rise is 2600mm and the available Going is no issue. ......

I presume this is domestic, and not commercial or in a block of flats or similar? Everything changes if it is.

The absolute rule number one with staircases is not to work from anyone else's measurements. Go to site and measure the FFL to FFL yourself, to the mm. It won't be 2600, I promise!! Ascertain any headroom issues (there must be a clear 2m above the nosings along the whole length of the stair). Make sure there is a clear landing available the same width as the stair (ie if the stair is 900 wide then the landing must be 900 x 900 minimum). Make sure there are no doors adjacent (I believe the stair must be 400 clear of any door swings, but would need to check on this).

Let me tell you there is a huge difference between 900 across the strings and 800. This is the difference between a wide stair and a narrow one. On the design of the rise and goings, remember this is to the nose of the stair, and that there must be an overhang (16mm, I think, is the minimum, again, from memory). Therefore a going of say 220 will involve a minimum tread depth of 236mm. With 2600 as the total rise, I would divide that into 13 rises of 200, and have a going just a little over the minimum 220. At 200 rise, the minimum going is 223. There is a maximum going, to, which varies with the rise. I'm afraid I refer to an old NHBC diagram for all my stair design criteria, and this isn't available online as far as I know. Stair design is not simple.

And finally, bore yourself witha little light reading........

 

[LBCarpentry]

Just been this morning to measure up.

The floor to floor rise is 2580mm

I calc the rise to be 215mm, Tread (minus the overhang) to be 239mm)

 

[LBCarpentry]

part K of the building regs covers stairs and is quite useful.

To add to what Trevanion said the maximum pitch is 42 degrees so you can't use the maximum rise with the minimum going.

There is a recommended ratio which is that the sum of twice the rise plus the going (2R+G) should be between 550mm and 700mm

having now done my sketch setting out, my ratio calculation falls at 669 and my pitch is bang on 42 degrees so I think im good to go.

 

[HOJ]

Just a note of caution when taking the measurements for the rise, I always get that at the point where the bottom tread/newels are to land, relative to the landing, quite often find floors run away, last one I did floor was 30mm different from the plumb measurement at the landing position.

I can also recommend a book: Mark Milner, Simply Stairs.

 

[MikeG.]

Just been this morning to measure up.

The floor to floor rise is 2580mm

I calc the rise to be 215mm, Tread (minus the overhang) to be 239mm)

I've just looked at this again. You are very close to the limits with these numbers. You say there is plenty of room for the stair, so did you at least try a 13 riser stair rather than a 12? It would give you a rise of 198.5, which is a much more comfortable number. You could then have a going of anywhere between 220 and 300. I try to avoid ever having a rise of more than 200mm. You're current numbers are for quite a steep cottage-type stair.

 

[Doug71]

As well as measuring I always mark the total height on a lath/rod, it saves any arguments later over wrong measurements or changed floor levels.