Thread: Exterior stairs for single family home

Hired someone to install concrete stairs on the exterior of my home in Maryland. The stairs lead from a driveway to the back yard and are about 4 feet wide. Four risers were required, but the treads are not level. I brought this up with the contractor and he insisted the slope is required to run water away from the house. I suspect he is just being lazy and doesn't want to fix it.

Is he wrong or should the steps always be level? The slope is easily seen by visual inspection without the use of a level (though I checked with a level as well). It appears to be more than an inch decline over about 3 feet.

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Originally Posted by Javier Z

the treads are not level. I brought this up with the contractor and he insisted the slope is required to run water away from the house. I suspect he is just being lazy and doesn't want to fix it.

Is he wrong or should the steps always be level?

Depends.

"How much" "not level" are the treads?

The treads may be (are allowed to be) sloped 1/4" per foot in the direction of travel (decsending or ascending the stairs) and/or 1/4" per foot cross-slope (across the direction of travel, from one end of the tread to the other end).

That is not a "design" parameter, the treads should be "level", the 1/4" per foot slope is a 'construction tolerance'. That means that is the contractor 'designs' the tread to be slope 1/4" per foot for drainage, the 1/4" per foot in the code is not a tolerance from his 1/4" per foot, it just means the contractor had better not miss his design of 1/4" per foot by even the slimmest of margins as the contractor is intending to hit the maximum allowed slope. Trying to construct anything to the maximum or minimum allowed is stupid because if you are not exactly precise in the construction ... you get to tear it out and do it all over again.

Architects "design to the maximum and minimum" all the time for stairs and do not realize it until it comes back and bites them in the butt - almost all architects specify stairs in building which are other-than-residential (often times referred to as 'commercial building' even though the buildings may be 'educational', 'institutional', etc.). The architects design to the maximum and minimum by designing all the stairways to 7/11, i.e., 7" riser and 11" tread ... the MAXIMUM allowed riser is 7" ... the MINIMUM allowed tread depth is 11" ... when the stairways come out with 7-1/8" risers and 10-7/8" tread depths, the stairs require A LOT of work to correct them to meet the maximum riser height of 7" and the minimum tread depth of 11".

Some respond 'What's and 1/8" of an inch?', the answer to that is typically in the millions of $$$$ by the time the case is settled.

Question: 'Will that 1/8" of an inch 'cause' the fall?' Probably not.
The better question is 'COULD that 1/8" of an inch have PREVENTED the fall? Possibly.

See the difference in the answer to the different questions about the same 1/8"? All one needs is "Possibly." and the decision will be 'then the stair should have been constructed within the limitations of the code' - that is why the code is there.

I had an architect call me today asking if the Commentary is enforceable, the answer is 'No, the Commentary is not enforceable, not unless the state actually adopts the Commentary along with adopting the code.

I won't go into the details, but my suggestion was to add a general comment to the affect that 'All materials, systems, components, and other items included in these drawings be installed in accordance with these drawings, the manufacturer's installation instructions, and the applicable code, the most restrictive of those shall take precedence.'

His fault without the note? If I get the work ... I will let you know ... I provided enough free information that he may be able to get off that hook himself. But, if not, hopefully he will call me to cut the line for him.

Originally Posted by Javier Z

It appears to be more than an inch decline over about 3 feet.

More than an inch over three feet is more than I would want to slope it. For exterior steps, a bit of slope is a good idea.
Having treads slope slightly in that direction actually makes for comfortable walking. Ever try walking on a set of stairs that slope the other way? Very uncomfortable. (I make quite a few stairs. When I divide the total rise to come up with the unit rise usually the resulting number is an awkward number. I always round down. This makes the treads slope down a bit but not enough that it can be seen without a level.)

Originally Posted by Bert de Haan

More than an inch over three feet is more than I would want to slope it.

With an allowed slope and cross-slope of 1/4" per foot, a 3 foot distance would only allow a 3/4" change from end to end.

When I divide the total rise to come up with the unit rise usually the resulting number is an awkward number. I always round down.

The correct way is to take the total rise (in inches) and divide by the riser height you would like, that will give the number of riser required for that riser height and it rarely equals a nice whole number, so round the number of risers up to the next whole number and divide the total rise by the number of risers you came up with, that will give you the riser height for each riser with all risers being equal (as they should be).

Example: Total rise is 11 feet 6 inches, or 127 inches, if you would like a riser height of 7-1/2" divide 127 by 7.75 inches = 16.39 risers, round up to 17 risers, 127 divided by 17 = 7.47 inches. To try for a nice even 7.5 inch riser height do this: 7.5 x 17 = 127.5 inches or 1/2 inch too high, so take that 1/2 inch and split it into 1/8 inch increments and make the first four lowest risers 7-5/8 inches - that takes up the extra 1/2 inch and keep the riser heights within the allowed variation of 3/8 inch (the riser height variation in my example is only 1/8 inch).

Why the lowest four risers? Because falling from the lowest four risers will result in less serious injuries that falling from the highest four risers (you are already at the bottom of the stairs). However, because that 1/8 inch variation is well within the allowed 3/8 inch variation between tallest and shorted risers the risk that the 1/8 inch will cause a fall is nearly zero, and will be much closer than most any stair one tries to measure accurately. If your workmanship is very good, then split the 1/2 inch into eight 1/16 inch risers, if you have a stair building jig and you can work to very close tolerances for woodwork, split that 1/2 inch into sixteen 1/32 inch risers, now there is only one riser different and it is only different by 1/32 inch - try to accurately measure a difference of 1/16 inch on a stair, hard to do, right ... now try to measure a 1/32 inch difference in riser height ... not even if you are using a tape measure and a level to measure riser height.

Originally Posted by Jerry Peck

7.5 x 17 = 127.5 inches or 1/2 inch too high, so take that 1/2 inch and split it into 1/8 inch increments and make the first four lowest risers 7-5/8 inches - that takes up the extra 1/2 inch and keep the riser heights within the allowed variation of 3/8 inch (the riser height variation in my example is only 1/8 inch).

You actually do it like that?

If you Google stair riser calculator, it is very easy to figure out.

- - - Updated - - -

Originally Posted by Jerry Peck

The correct way is to take the total rise (in inches) and divide by the riser height you would like, that will give the number of riser required for that riser height and it rarely equals a nice whole number, so round the number of risers up to the next whole number and divide the total rise by the number of risers you came up with, that will give you the riser height for each riser with all risers being equal (as they should be).

This is the exact way to calculate it.

Originally Posted by Bert de Haan

You actually do it like that?

Yep.

It is easier than you may think - try it, you'll like it.

Keep in mind that if the overall height difference from one level to the next level measures out as 12 feet+ ... a landing is needed, does not matter how much over 12 feet it is, still needs a landing.

With a landing there are now two flights of stairs, and while each flight of stairs must have the same riser heights and tread depths all the way, the riser heights and tread depths of the next flight are allowed to be different than the previous flight - the landing allows one to change their gait and re-adjust to the change for the next flight of stairs.

I know how to calculate it but I was wondering if in a situation like that, Jerry actually makes the bottom risers a different size than the rest of them.

Originally Posted by Bert de Haan

I was wondering if in a situation like that, Jerry actually makes the bottom risers a different size than the rest of them.

Sometimes, yes, sometimes, no. I like the riser heights to all be the same, but sometimes the measurements do not divide out that way (who uses a tape measure with lines at decimal points instead of at fractions?).

I had some engineering for some windows I was inspecting which specified that the anchor screws maximum spacing as 13.97 inches ... who cares a tape measure which measures 13.97 inches? 13-31/32 inches = 13.96875, if the engineer wanted a maximum spacing of 13-31/32 then just say so, but if the maximum spacing allowed is 13-31/32 inches, the slightest wobble of the drill off the mark puts the spacing at 14 inches - or more - ... did the engineer really think that 0.03 inches makes that much difference? They must, so I said, 'Well, I guess 13.97 inches is *just shy of the mark for 14 inches* on my tape measure ... '

Some engineers need to get real. Just because they are in the office using a computer program which spits out dimensions to 20 decimal places does not mean the person installing the product has the capability to measure to anything close to that. My tape measure is marked in 1/16 inch increments, which means that 'halfway between the 1/16 inch marks is approximately 1/32 inch, and 13.97 if 'just a little bit more than 31/32' ... yeah, right - when pigs fly ...


Which is better:
a) have a riser which meets the code of 3/8" variation at the top or the bottom
b) even the riser heights out by making slight adjustments to a few risers

Which is easier? Wait, that is rather obvious and does not need an answer.

Originally Posted by Jerry Peck

Sometimes, yes, sometimes, no. I like the riser heights to all be the same, but sometimes the measurements do not divide out that way (who uses a tape measure with lines at decimal points instead of at fractions?).

Canadians, Europeans, Asians, Africans, ....

I had some engineering for some windows I was inspecting which specified that the anchor screws maximum spacing as 13.97 inches

10.1 cm, easy one.

Which is better:
a) have a riser which meets the code of 3/8" variation at the top or the bottom
b) even the riser heights out by making slight adjustments to a few risers

Which is easier? Wait, that is rather obvious and does not need an answer.

You are probably right, but if you are measuring from the subfloor, always add the thickness of the floor covering to the floor. So make that first step a little higher. Outside, not.

I make my risers and treads all the same. Making an adjustment on four risers means I would have to reset the jig four times on each stringer. (If both the riser and the tread increase a corresponding amount, you would only have to reset the jig once per stringer.)

About the strange measurements that engineers require sometimes, the Ontario Building Code was full of them. I believe this was due to an earlier attempt to convert to Metric. These numbers were then converted back to imperial. That problem is now "solved" by having all the measurements in Metric again.

Originally Posted by John Kogel

Canadians, Europeans, Asians, Africans, ....

Fortunately for me, we are in the USA.

10.1 cm, easy one.

Then the engineer should have written the measurements in cm ... but did not. And if he had I would have shoved the instructions down his throat ... ... because we still use feet and inches here. I did inspect some mini-split air conditioner units which had all clearances and dimensions in cm ... took a lot longer for the inspection because I had to mentally convert cm to inches - the clearance on the outlet side of the condenser unit fan calculated out to 80 inches clearance to anything - when I got back to the office I went online and rechecked the conversion ... I was about a 1/2" off was all.

You are probably right, but if you are measuring from the subfloor, always add the thickness of the floor covering to the floor. So make that first step a little higher. Outside, not.

Bad mistake to make doing that.

The first thing is to find out what floor covering are going where, which not only includes the lower floor covering and the upper floor covering, but also what is going on the stair treads - all the floor coverings may be the same finished thickness, which would make any adjustment for them as the cause for the lowest and/or highest risers not being correct.

I've had stair installers make that very mistake - it really is a shame to turn down a final inspection because of poor planning on the contractor's, designer's, owner's part. Can't fix 'stoopid', but that does not mean that 'stoopid' gets a free pass either. Recently had a staircase $20,000 marble on it which was off by an inch at top and bottom, and the treads were too narrow, with the risers being too high (they tried to cram a beautiful staircase into too small of an area, now someone is trying to figure out who to blame so that person can pay to correct the stairs - I am pretty sure who is at fault ... all of the above as no one checked with anyone else to see if the stairs would fit - let them all share in the cost, the cost is not my problem ).

Finding uneven stairs as result of changing floor coverings is super common from what I've found. Even in new construction I see it get missed all the time. It's almost always at the top and/or bottom stairs and is due to someone not taking into consideration the floor covering (or changing midstream).

At least a half dozen times over the years I've had clients (or agents) roll their eyes when I bring it up and then within 30 seconds stumble on the exact set of stairs I was just talking about - Being a nice guy I usually pretend not to notice

The same thing happens with tripping hazards on walkways and driveways. Maybe I just had too many drunk buddies in my younger years but these seemingly minor variations are a big deal IMO.