Stairs. Most of us use them every day without thinking. Nearly every home has a set or two; from steps into the house, steps getting us into the basement, or even the staircase that takes us to the ...

A Facebook page, which began among a few friends, has grown into a popular photo collection of hazardous stairs. A staircase made of pipe fittings at Kevin Reid’s childhood home in Dublin, Ireland.

Amateur carpenters who have laid out the cuts in a stair stringer (the zig-zag structural support for the steps) know the queasy feeling that bubbles up at the prospect of this job. There’s the simple ...