Hyderabadghar/Do it your self/How to Plan Your Stairs

PROJECT BASICS

Project: Easy
Estimated Project Time: 1 hour
Estimated Project Cost: Varies with the project
Start Tips: Plan the style and location of your stairs according to ease of use, expense, safety, local codes, and your own carpentry skills.
Safety Tips: If your stairway is wider than 36 inches, you'll need to install a notched middle stringer to support the middle of the treads.
Recommendation: Do-it-Yourself

Fig. 1

INSTRUCTIONS

1) Unit run and unit rise
The most common tread for an exterior stairway is made of two 2x6s or one 2x12.

Typically, you'll leave a 1/2-inch gap between two 2x6s for a tread depth of 11-1/2 inches. Subracting about 1/2 inch for an overhang leaves a typical step depth of 11 inches. The depth of one tread is known as the unit run.

A typical vertical distance between steps, known as the unit rise, is 7-1/2 inches. This 7-1/2 inch rise and 11-inch run combination is common for interior stairs. Moreover, it satisfies nearly every local building code. (Fig. 1)

Fig. 2

2) Adding risers
Riser boards not only fill in the spaces between treads, they also help support them. However, their support is only a sort of bonus—it cannot take the place of a middle stringer needed for stairs wider than 36 inches.

The front of each tread rests on the riser below, but the rear of the tread is supported only by a nail or screw driven through the bottom of the next riser (Fig. 2). If the stairway's constructed so this nail alone keeps the tread from flexing, the riser may crack near that nail; this problem is common with underbuilt stairways.

Fig. 3

3) Stringer designs
Choose one of three types of stringers: notched stringers, housed (solid) stringers, or housed stringers with a notched middle stringer (for two-by treads wider than 36 inches). All are cut from 2x12s.

Fig. 4

Notched stringers
Notched stringers, cut so that each tread rests on top of a notch, are most commonly used (Fig. 3), but have drawbacks:

though cutting notched stringers does not require a great amount of work, any measuring mistakes are difficult, if not impossible, to correct once the cuts are made
notched stringers also are prone to cracking, both during construction and in the years to come, since each "tooth" juts out and can easily be broken off
every stringer's top edge exposes end grain to the elements, subjecting it to rot

But notched stringers and overhanging treads admittedly impart a classic look. And stairs wider than 36 inches will need a notched middle stringer anyway. With careful work, you can build a stairway with notched stringers that will last for decades.

You can buy precut, notched stringers at lumberyards. And, if the exact location of your bottom pad doesn't matter, you can adjust its position to accommodate the precut stringers. Determine the rise and run before purchasing your stringers, and make sure the bottom step won't differ more than 3/4-inch from the others.

Fig. 5

Bottom landing pad designs
Since stringers need something solid to support them at the bottom and to keep them from ground contact, they usually rest on a pad made of concrete, masonry, or gravel. This pad can be a small area just under the stringers or it can extend beyond them to become a path.

You must determine the location of the pad and construct it before installing the stairway; this will be time-consuming if you're pouring a concrete pad. Instead, you might choose a solidly constructed patio surface—not only does it look better in many situations, it can be installed relatively quickly, and you don't need to wait for the concrete to set. If you will not have rail posts attached to your stringers, it's advisable to anchor the bottom of the stringers to the pad (Fig. 5). If you know where your steps will end, you can install J-bolts there while the concrete is wet. But anchoring can also be done after the concrete is set and the stringers are in place.

Railing posts
If your stairway will have a railing, the railing posts should be installed in conjunction with the stairs. Whether set on top of footings or sunk into a concrete-filled hole, the posts will help support the stringers. It's recommened that rail posts be sunk into the ground since those resting on footings have little lateral support, and may flop back and forth after only a few years.