# Forum Home Renovation Stairs, Steps and Ramps  stringer size

## pyro_15

Does any one know what the requirements for stringer size are? 
I've not made my mind up whether to go for an open or closed stringer. So I'm after a few things. 
I'm after the min throat (distance between the corner where the rise and run meet and the back of the stringer) for open stringers. 
For closed stringers is the a minimum amount of material that has to be left when the tread and risers are routed out. 
I'm looking at a U shaped stair top section is about a 3.1 span and bottom section 2.3m span.
is there specific sizes required for those spans. I'm looking at making the stringers out of pine. 
Thanks for all your help.

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## Bloss

You need to give more info on where the stairs are being used. In any case there are some good calculators at our forum member Blocklayer's site that'll help: http://www.blocklayer.com/Stairs/Default.aspx

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## pyro_15

internal stair case, residential.

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## pyro_15

What is the "standard" size used for stringers?

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## Bloss

> What is the "standard" size used for stringers?

  None - they vary according to step size and other design factors that's why you should look at the site. As to housing - again you can have fully routed open at both edges of the stringer or use cleats or housed closed to the front or front and rear. Most of the choices are to do with the look that is sought. Have to say that stairs are one of the hardest things for a DIYer to do. Not impossible, but there is reason most builders now days use specialist stair manufacturers who design and build and deliver on site as fully or partially built, or in components.

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## pyro_15

thanks bloss, 
 I've checked out the web site its great for working out the rise and run, unfortunalty it does not "calculate" the "stringer width", the page it asks for it as a constent. 
I'll probably go the housed closed front and rear for athestics and little less more forgiving when being accurate then the routed. 
A few stair building websites mention 300 x 25 and 250 x 50 giving me a min throat of 158 and 108 respectivly. 
Any input?

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## pyro_15

bloss, if you have access to stringer span table would you mind checking if
900 tread, f11/mpg15, 200*50 has a 2800 span.

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## TermiMonster

According to my tables, a 200*50 R.P. stringer has a max of 12 treads@750mm width, 11@1000mm.
Trenching is nominally 10mm to accommodate treads.
HTH,
TM

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## pyro_15

Thanks,
That's termimonster exactly what i was after.

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