stair slope rules?

[lotechman]

I often use the 70 -75 rule when building stairs but am curious about how others do it. I keep giving away my old copies of the national building code. The new ones are hundreds of dollars.
The rise times the run should be somewhere between 70 and 75. For example if you have a rise of 8 inches your run should be between 9.375 and 8.75 inches.
Any other methods?

[stumpster]

Huh, my dad taught me the 7/11 rule! Stay as close to But no less then 7" rise and 11"run, but we did nosing's so it would end up at 10". We would also knock the nose out of level just a tad so you don't feel it in your calves (no more then 2%).
When I built them I was always within a 1/6 of all dimensions but I think you have a 1/4 inch or so tolerance.
I've built around 20 of these since I was 16 and never failed an inspection!

[Brett]

In Australia we use a different rule

Treads must be between 355mm -240mm 14"-9 1/2"
Risers must be between 190mm-115mm 7 1/2"- 4 1/2"
Riser x2 + Tread must be between 700mm and 550mm 27 1/2"- 21 1/2"

(You Yanks use funny lengths :) )

[leeroy]

right you are brett :)

[lotechman]

In Australia we use a different rule

Treads must be between 355mm -240mm 14"-9 1/2"
Risers must be between 190mm-115mm 7 1/2"- 4 1/2"
Riser x2 + Tread must be between 700mm and 550mm 27 1/2"- 21 1/2"

(You Yanks use funny lengths :) )

I prefer metric if possible. Being Canuck I have to switch back and forth all the time. I find it interesting that your rise maximum is 7.5 I run into the occasional rise closer to 8 but it is often for sawmills and the like.

[Sandy]

(You Yanks use funny lengths )

No way!!!

Just looky; a nice simple 11 inches would be 279.4 of those mm things. My tape doesn't even have any mm's on it that I can find. Besides that those mm's are such tiny little things I have to clean my glasses to even find 'em.

:D

[lotechman]

No way!!!

Just looky; a nice simple 11 inches would be 279.4 of those mm things. My tape doesn't even have any mm's on it that I can find. Besides that those mm's are such tiny little things I have to clean my glasses to even find 'em.

:D

Actually Sandy metric is much better. There are no meters or centimeters. Everything is Millimeters. Yes this is true even with huge highway overpasses I have been involved with. You simply say "Thirteen five eighty nine" or " twenty seven five twenty three"
The big plus is no fractions. Checking and summing running dimensions is so much easier.
Here in Canada anything that is a government project must be metric and in the last ten or fifteen years private industry has followed.
Your eleven inches would likely be rounded to 180. After all what is a mm between friends.
Bevels are given in 250. If you are given a total stair rise of say 8 ft - 2 inches start dividing that up to find how many risers you should have. I get 13 risers and 7.538 inches each. You have to account for that 38 thousandths or 13X38 gives you a .494 ( half inch missing)
In metric 2489 mm rise divided by 13 risers gives me 191.46 or simply 191 mm. No fractions or conversions to decimals etc. 13 X.46=5 mm missing which is manageable. ( less than half the cumulative error)

[Brett]

I prefer metric if possible. Being Canuck I have to switch back and forth all the time. I find it interesting that your rise maximum is 7.5 I run into the occasional rise closer to 8 but it is often for sawmills and the like.

Yes, I'm 46 so I learnt in imperial and all the tradesmen I learnt from used imperial , but I use metric now and couldn't imagine imperial being easier though I do switch back and forth.... much to the consternation of the younger blokes who work for me.

A 7.5 inch riser is big and would be avoided if possible, same goes for the two extremes of the ratio. A 6 to 6.5 inch riser with a 10 inch tread is an "easy going".

We here in Oz also have to be aware that we cant have a gap of greater than 125mm daylight between underside of upper tread and top of the lower tread to comply.

[Brett]

>>>We here in Oz also have to be aware that we cant have a gap of greater than 125mm daylight between underside of upper tread and top of the lower tread to comply.


Opps that is if you dont have a riser installed

[lotechman]

>>>We here in Oz also have to be aware that we cant have a gap of greater than 125mm daylight between underside of upper tread and top of the lower tread to comply.
Opps that is if you dont have a riser installed
Wow! that would put a damper on some of the designers ideas around here! A lot of private stuff I have done over the years had completely open stairs with no risers. I know it puts a few people off who are frightened of heights when they can see through the steps.
I can recount endless problems with designers switching back and forth between metric and Imperial. The most stupid was an oil company inspector stopping work on a distillation tower we were building. The trays were at 612 spacings. When I came back on shift the next day he kept repeating to me: "You are 5/8ths of an inch out!" My print was in metric but he was checking for two foot spacings over 20 metres of the tower. The guy had held up the job for a complete shift. He was not popular and I was in his sights from then on.

[Brett]

Wow! that would put a damper on some of the designers ideas around here! A lot of private stuff I have done over the years had completely open stairs with no risers. I know it puts a few people off who are frightened of heights when they can see through the steps.



Not really, in a timber stair its easily achievable with 1 and 1/2 to 2 inch timber with a 5" daylight gives you a 6 1/2" to 7" riser. In metal you will often use say 1/4" plate in that case a simple fold down gives you the rigidity needed and your gap.
Its frustrating as in most cases the council (our inspecting body) are not aware of the full BCA (Building Code Of Australia) and often nor are a lot of contractors .

[Brett]

Oh and by the way the code allows for spiral stair cases in a different section with different specifications.

[Gyrocopter1]

The way I always did it was two risers and one tread equal 25". Usually the distance between floors or platforms of a house ect. is a set distance,divide that up between seven and a half to eight inches , add two together whatever is left to equal 25"would be the stair tread.The main thing is all risers are the same ,sometimes the run will be shorter or longer to fit a certain meas. on fire escapes anyway. Gyrocopter 1. over and out

[Bob Warner]

I saw a guy on "This old house" take a square and clamp a 1X2 across it at an angle. He said that you can do anything you want as long as the two numbers equal 17". You just clamp the 1x2 across your measurements and put it on the 2x12 and mark it and slide it up and mark it again, all the way up.

[littlefuzz]

I've used the 7-11. I'm glad we hadn't converted to the metric system, Fractions are so much easier to me. There's a guy I know that builds bridges for the county and they used 1/10 of an inch? That sounded kinda messed up to me, i've never seen a tape that reads 1/10ths.

[Gyrocopter1]

My two cents worth. Two risers and one tread should equal 25" ,= two 7" risers = 11" tread total 25". 6" risers = 12" tread , or as close as possible to 25" ,at least thats the way it was in Brockton Mass.in the 80'S building fireescapes and pan stairs for apt. bldgs.ect. Littlefuzz your right on.

[IHDonnie]

I've used the 7-11. I'm glad we hadn't converted to the metric system, Fractions are so much easier to me. There's a guy I know that builds bridges for the county and they used 1/10 of an inch? That sounded kinda messed up to me, i've never seen a tape that reads 1/10ths.


It's actually 1/10 of a foot. Standard surveyors measurement.

[lorenzo]

I've used the 7-11. I'm glad we hadn't converted to the metric system, Fractions are so much easier to me. There's a guy I know that builds bridges for the county and they used 1/10 of an inch? That sounded kinda messed up to me, i've never seen a tape that reads 1/10ths.

1.2 inches is equal to 1 on a 10th scale, so 6 inches on your tape would be 5 on the 10th scale

[Mondo]

I built and maintained stairs and walkways in a natural recreational park (Lost River Gorge, North Woodstock, NH) for four years a while back (late 80's). We used the formula 2R+T~ 24 to 25 inches meaning twice the rise plus the tread depth came to some value between 24 and 25 inches. Other requirements included no rise over 7 3/4 inches, no two adjacent rises could be more than 1/8" difference and no total difference overall could be more than 1/4". Anything outside that formula would be awkward for humans to walk either up or down.

Another limitation usually required (but from which we were exempted because of the awkward location in which we built the walkways) was no more than ten rises between landings of 36" minimum each.

The last time I checked architectural standards required the treads to be a minimum of 11.5" nose to nose with 3/4 to 1" overhang on the nose.

The trend for public access is deeper tread and lower rise, mostly pushed by the Insurance industry. The less the tread depth the more likely people will miss a tread going in either direction, the greater the rise the more likely people with kick the next riser going up and release the weight from the trailing foot too soon going down. The former causes banged shins, wrist, hand, and face injuries, while the latter causes long tumbles with a multitude of nasty injuries.

For those who like history, in previous ages it was common for residential stairs to be narrow in both width and depth, and for risers to be tall, all because space was at a premium. It was also common to find at least one step had a rise of at least one inch greater than all the others, placed at some random location within the stairway. This was the "trip step" which would foil an intruder in the middle of a dark night while the regular occupants of the home could scamper up and down the same staircase with ease.

As our society becomes more advanced and we become more accustomed to easy living we also become less adept at navigating our increasingly clumsy bodies through our infrastructure. Negotiating steep narrow staircases has become a challenge, with ladders being nearlyimpossible for many.

[Mark...]

You will also find variations in certain codes between residential/commercial

[William McCormick Jr]

Actually Sandy metric is much better. There are no meters or centimeters. Everything is Millimeters. Yes this is true even with huge highway overpasses I have been involved with. You simply say "Thirteen five eighty nine" or " twenty seven five twenty three"
The big plus is no fractions. Checking and summing running dimensions is so much easier.
Here in Canada anything that is a government project must be metric and in the last ten or fifteen years private industry has followed.
Your eleven inches would likely be rounded to 180. After all what is a mm between friends.
Bevels are given in 250. If you are given a total stair rise of say 8 ft - 2 inches start dividing that up to find how many risers you should have. I get 13 risers and 7.538 inches each. You have to account for that 38 thousandths or 13X38 gives you a .494 ( half inch missing)
In metric 2489 mm rise divided by 13 risers gives me 191.46 or simply 191 mm. No fractions or conversions to decimals etc. 13 X.46=5 mm missing which is manageable. ( less than half the cumulative error)

Fractions are cool, and you can express ratios exactly. Some calculators now do fractions too.

Fractions are pretty easy to work with once you do a couple calculations.

Check this out it shows exactly how easy they are.

http://www.Rockwelder.com/Flash/Fractions/Fractions.html



Sincerely,


William McCormick

[sprocketwerx]

I keep getting thrown one way or another on the measuring scale. I learned fractions in school as a kid, decimals and metrics got thrown in in the 90's when I got into automotive prototype work, went back to fractions and decimals in aircraft industry, and now a bit of both in drag racing(imp) and motorcycles(metric).
I find I need to occasionaly retrain myself in either discipline when switching over and over, and over....
Why can't we all just get along?!?! LMAO

[oxygen454]

I agree with Mark. Check your areas building codes and go from there. Remember rise over run lol. After so many steps, you also have to have a landing.

[Brett]

You may find this useful:
Its in metric...


http://www.blocklayer.com/Stairs/Default.aspx

[comp]

You may find this useful:
Its in metric...


http://www.blocklayer.com/Stairs/Default.aspx

cool link :D

[johndeerski]

In oregon the way I was tout its- no less then 4'' and not verein more then 3/8'' with a 12'' tread. on spirul stiars its measred in the middle.

[weldbead]

spaammer

[Ironmower]

Nothin' over 7" riser 11" tread with a 1" toe space. laid out in pairs. No more than 1/8" between steps and no more than 3/16" over the whole run.............No need to pray, I'm buildin' my stairway to heaven!!!!!!!!!!!!!