Key to safe stairs is a magic formula
Q: I asked a contractor to build a set of porch steps using name-brand materials. He made a mess of it, and when you step off the last step, you trip on a sloped piece of concrete he added. I know you can’t tell me how to build steps in a short column, but what can you tell me about the rise and run of porch steps? — Wanda G., Bremerton, Washington
A: Your photograph makes me cringe. I’ve seen quite a few botched jobs in my time, but yours may be in the top 10. I hope you didn’t pay for this work.
You’re right that I can’t give you step-bystep instructions about how to build stairs. To explain the job adequately would take a small book. But let’s talk about rise and run.
Long ago, architects and builders discovered a magical relationship: the sum of the height of two risers and the width of one tread had to be no less than 24 inches and no greater than 26 inches. Any total between those two numbers was acceptable.
For some odd reason, this requirement was removed from the modern building code.
You might wonder how these two numbers were selected. If you could ask long-dead architects and builders about the safest steps they ever built, most would say the risers were 7 inches and the treads 10 inches. Do the math and you’ll find this combination adds up to 25 inches, exactly halfway between the range prescribed by the past code.
In your case, all your builder had to do was make sure the vertical distance between the top of your porch and the landing under the last step was some multiple of 7 inches. If this meant he had to modify your landing at the bottom, so be it. But he tried to make the modification in a short distance and created a small ramp that’s extremely dangerous.