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Stair riser height

Posted by Ariadni6 (My Page) on
Sun, Jul 17, 05 at 12:21

We had stairs from the kitchen to garage replaced as a part of a kitchen remodel. The carpenter said he was making the riser height the same as in our foyer (7.5 inches). The stairs are finished and I noticed that they seemed harder to climb up than other stairs. When I measured the riser height it is 8.5 inches. I think this is too high, but I don't know what "code" is. If it is considered too high, should I ask them to redo it? I can imagine how that will go over -but DH has bad knees and we are middle-aged. TIA.


Follow-Up Postings:

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RE: Stair riser height

The formula I remember for comfortable steps is the twice the riser plus the tread should equal 24 inches. With a 8.5 inch riser, the tread should be about 7 inches. This puts you close to ladder dimensions in my way of thinking.


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RE: Stair riser height

Some codes have permitted maximum riser height in the neighborhood of 8 1/4". Some now limit it to 7 3/4". Changing any part of a stair riser or tread changes everything except width. Lower risers mean more risers and treads. More treads means greater horizontal run (length). 8 1/2" is considered steep. Do discuss this with the stair builder. Please tell us what he says.


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RE: Stair riser height

I know nothing about codes, but I remember an article from years ago reccomending that all stairs be made wider and with shorter risers to accomodate the way we actually move from an ergonomic point of view...

8&1/2 sounds uncomfortable, will be a real problem if anyone develops bad knees or the like.


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RE: Stair riser height

I am comfortable with the 6" steps at the physical therapy clinic I visit. I have 7" on the steps to the back door and they are just okay. Those steps replaced a nasty set that varied between 9" and 11". If you have the room (run), I'd advise having them made much shorter. How many steps are there? One extra riser may do the trick. Of course, that means tearing it all out and starting over, but it really does need to be done if DH is having difficulty now with them. It will only get worse.

I thought code said no higher than 8". At the site below, it says 7.75" is the high end of most codes. They have a great calculator there.

Here is a link that might be useful: Staircase calculator


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RE: Stair riser height

Thanks for your responses and the calculator. There are 7 steps and there is plenty of room to make the risers lower and the stairs extend out more. The main problem is convincing the GC to redo the whole thing. It took the carpenter 3 days the first time around plus the handrail has been painted. Would you ask for it to be redone? I'm sure the GC will be pretty perturbed and say something like "this is the way they always do it and noone has complained...." Thanks!


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RE: Stair riser height

To be a little more prepared for your GC you might just make a call to the local city building dept. and ask them code requirements for rise & run of residential stairs. Then if he tells you "this is the way they always do it and no one has complained...." you will have an answer.

I believe 8 1/2 inches will not meet code requirements.


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RE: Stair riser height

The International Residential Code---the basic code book most codes start with gives a maximum riser height of 7&3/4".

What the carpenter did on your stairs is make the riser height 7&1/2"---and then added the one inch thick treads. Which is a nono. What should have been done is design the total height at 7&1/2"----meaning a basic or rough riser height of 6&1/2" to which the one ince treads are added for a total of 7&1/2".

The reason the stairs feel uncomfortable is because of something called muscle memory. People learn to clinmb stairs early in life and the muscles in your legs get a 'memory' of how high to raise a foot to climb stairs. The same uncomfortableness happens with steps that are too short---people expect that 'muscle memory' drop and their foot hits too soon---causing them to stagger or stumble.


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RE: Stair riser height

To avoid confusion about the riser height, the FIRST riser is cut to the specified height MINUS the thickness of the tread. Measuring from the tread cut on the stringer for the first tread, each suceeding riser is measured full height. The last riser height depends on how and what is the last tread.


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RE: Stair riser height

I think I would disagree with you handymac. I think the height of the risers would in the end be the height of the stair if each tread is the same height. Each tread would be 1" thick so the height of each stair would be raised 1", negating the rise from the tread. For example, if you have 10 stairs with a 7" rise that is 70". Adding treads will not sudddenly make each rise 8" and the overall staircase rise 80". However the top and bottom riser height would be dependent on the finished floor. The finished floor may not be 1" thick and would need to be adjusted if an equal rise were desired.

Correct me if I am wrong.


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RE: Stair riser height

The 2003 Kentucky Residential Code supplement, effective 3-24-03, (a revision to the 2002 code), states the following:

R314.2 Treads & Risers Amend the first sentence of the section to read as follows: " The maximum riser height shall be 8 1/4 inches and the minimum tread depth shall be 9 inches."


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RE: Stair riser height

The Uniform Building Code stipulates that residential stairs be a maximum of 8" rise and minimum 9" run. That means your 8.5" high stairs do not meet the code (if this is the code in your area). The contractor needs to re-build them. If he refuses, have the building department inspector come out and make a determination.


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RE: Stair riser height

Thanks for looking this up for me! I will tackle this in my morning phone call. Treebeard - did you find that online?


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RE: Stair riser height

Masiman, I was simply explaining what happened in thae case of the original poster. You are correct in saying the riser/tread height should be figured into the design. Many folks see the measurement of a 7" riser height and cut the stringers to than 7" figure---when adding treads makes the total step 8".


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RE: Stair riser height

Yes, I found it online. Having been in the design and construction business for about 35 years or so, I've found that more often than not the internet is quicker than me going to our library in search of an answer.

I simply 'Googled' for "Kentucky Building Code"...and there it was.


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RE: Stair riser height

Handymac, for 7" rise, the bottom riser would be cut (in the stringer) to a smaller dimension, calculated by subtracting the thickness of the tread from 7". All the rest of the risers would be cut 7". That is the correct information!


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RE: Stair riser height

We had a house with one riser that was about an inch shorter than the rest. We, at some point, all wiped out on that tread and fell down the stairs. You reeeeeeeaaaallly want all your stairs in the house to be the same. When I bought this house I actually measured each riser. The realtor thought I was nuts...


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RE: Stair riser height

Now a retired builder, I have worked in five states and two Middle Eastern nations. In the U.S. most jurisdictions follow the International Building Code (IBC) but cities and states often amend or add to these codes in order to better build for earthquakes, windstorms, fire zones, or flood plains.

The main thing is to make every riser height the same since the human brain seems to program a whole flight of stairs after only a step or two. To have a different riser height thrown in a flight can then throw a person who gets used to not watching their steps. Some building inspectors in California wouldn't allow for more than quarter inch variance for a whole flight of stairs. The carpenter early on will build the stairs correctly then have a carpet or tile contractor screw up the finished product by changing the specified floor covering, which then, especially at the bottom or top step, can "throw" or trip a person who has become used to a certain measured step.

I have built residential stairs to maximum riser height from 7.75 to 8.25 inches depending on the code for an area. Riser height is often dictated by the economics of expensive square feet needed for stairs. Some folks with health problems have custom risers specified as low as 5 or 6 inches but inspectors seem not concerned with minimums.

I once lived in a villa in Riyadh, Saudi Arabia that I swear had every riser a different height. It was a problem navigating those stairs that also didn't have hand rails. Found windows, doors everywhere in that house out of plumb and level so evidently a level was never used. No wonder earthquakes in certain parts of the world are so fatal to populations where buildings are often thrown up it seems without blueprints, engineering, or inspections. Bribes can forgive shoddy practices, too, maybe even here in the USA.


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RE: Stair riser height

The 2006 IRC is the most recent and universal code for stair design. It gives 7-3/4" as the masimum rise, with no more than 3/8" variation in tread height within a given stairway. I have been building stairs for 40 years and prefer 7-1/4" rise in my own home. Below is a link to the stair section of the 2006 code. Cyril Caster, Fine Handiwork

Here is a link that might be useful: 2006 IRC Stair Design Guide


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RE: Stair riser height

Masiman is correct and Handy Mac is not. The rough riser height is the same as the finished riser height in the middle stairs no matter what the thickness of the tread is. However the bottom step is going to be taller than the middle steps by the thickness of the tread unless the builder reduced the bottom step height by cutting the lower part of the stringer. Which leads me to ask Aradni6 where he measured the step height. If you measured the fist step and the builder did not compensate by 1 inch (assuming the tread thickness is 1 inch) then the first step will be 8.5 inches tall and the middle steps will be 7.5 inches tall.
I would also like to know: Was this a replacement set of stairs that used the old stringer? If so, the builder has no control over the riser height because it is based on the already installed stringer.
If this was a set of stairs that did not previously exist then this brings up other issues. If this is the case in a remodel most likely the space was cramped and getting the stairs to make the rise is going to result in one of two things: Either the rise is too high per step or the tread length is too short to comply with code or both. Can you give more details about this remodel and also tell us the height of the first, middle and last steps so we can advise you properly when you tussle with the builder?


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RE: Stair riser height

Um, jgpenfield---you are aware the original post was made on
Sun, Jul 17, 05 at 12:21---almost 5 years ago.

Just for grins, I am correct in what I said. I did not say anything about the change between different risers. I said I thought the builder made a 7&1/2" tall riser and then added an inch with the tread. That is a total of 8&1/2" for the height of each step---not including the bottom or top step heights, which could be different.

8&1/2" tall steps cause many people to stumble when ascending the stairs and be off balance when descending. That is due to long term muscle memory from using 7&1/2" high stairs.


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RE: Stair riser height

"The rough riser height is the same as the finished riser height in the middle stairs no matter what the thickness of the tread is. However the bottom step is going to be taller than the middle steps by the thickness of the tread unless the builder reduced the bottom step height by cutting the lower part of the stringer. "

And everyone is ignoring the difference between the sub floor the carriage rests on and the finished floor that may be installed.

Now you know how often stairs gets screwed up, especially at the top and bottom.

The finished floor matters at each end.


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RE: Stair riser height

What handimac is saying is only true of a single-riser set of steps. A stringer/carriage is sawed with the rises all equal, the figure arrived at by dividing the total rise by the number of risers. If affixing to subfloor, only the difference between flooring thickness and treads must be held back from the first riser cut. If sitting on flooring (or a shim in lieu of it) an entire tread thickness (1") is backed off the cut. When treads are added they are added to all of the flat cuts of the stringer, so the riser remains constant , up to the last tread. Then when the flooring is added to the top landing, that will also come out even, because you already compensated for the difference in thickness at the bottom of the stair. You have to keep in mind the phrase "finish (material) to finish", rather than "framing to framing" when measuring/cutting stairs, then "back off' the bottom cut to compensate for the material's non-uniform thicknesses (flooring @ 3/4" vs. treads @ 1").
OK, take it easy.
Casey


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RE: Stair riser height

In the attempted drawing below if each line of text is is one inch then the riser is 4 inches tall and the tread is 1 inch tall. The height between the steps ( the top surface of each treader where you place your foot) is 4 inches. The height of each step = height of the riser=height of the vertical part of the stringer. In your specific case if you add 1 inch at the upper step from the upper tread and take 1 inch away at the lower tread the net gain from the treads is zero and the height of each step will be 7.5 inches=the height of the riser. It will not be 8.5 inches.
---------- ___________
----------(__________ top treader
-------------ll
-------------ll riser
__________ll
(_________ll bottom treader

This assumes the builder placed the risers behind the treads. If the riser is placed on top of the bottom tread and not behind it then the height of the steps will be 1 inch greater than the riser. But the height of each step will still equal the vertical rise of the stringer.
The flooring at the top landing and the bottom landing does affect the top and bottom steps but this was too complex to include in the discussion. The stair builder might not know what the flooring is going to be before the stairs are built or it might change during construction making the top and bottom steps off.


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