QA

Question: How To Lay Out A Stair Stringer

How do you calculate the angle of a stair stringer?

Measure the distance from the landing the end of the floor where the top of the stairs will mount. Write down the dimension — run. Divide the rise by the ideal step height. For example, a rise of 78 inches divided by a step height of 7 inches for 11.14 steps in each stringer.

Can I use 2×12 for stair treads?

Stair treads may be made of a single 2×12, but are often made of two decking boards or 2x6s. A stringer is a wide board, usually a 2×12, that runs at an angle from the landing pad to the deck framing and supports the treads. The stair treads should be at least 36 inches wide.

Are stair stringers 2×10 or 2×12?

It is acceptable and within building code guidelines to use either 2×10 or 2×12 dimensional lumber to create a set of stairs; however, a stair stringer should not be less than 3.5 inches wide at its narrowest point to provide adequate strength for the load the stairs will be supporting.

How long of a 2×12 do I need for stairs?

We suggest 10.5″ for 2×12 or 2 – 2×6 Treads. Treads may be cut to suit other widths. Either B or C is required.

What is the best angle for a staircase?

Stair codes and guidelines prefer an angle of around 37° for normal stairways (the green area in our illustration) and around 7° for ramps (the yellow area in our illustration). Steeper slopes or angles are permitted for stepladders in certain applications as you can see in the illustration.

What size lumber is used for stair stringers?

Stringers should always be cut from 2x12s. Notching smaller stock doesn’t leave enough wood to safely carry the loads of a stair. When ordering stringers, allow about 14 inches of stringer length for each step. Look for straight stock with as few knots as possible.

How far apart should stair stringers be?

Deck stairs are typically made from 2 x 12 stringers spaced about 12 to 16 inches apart. They rest on a solid foundation and are attached to the deck with hangers. They have risers (also called toe kicks), treads and railings. The stairs should be at least 36 inches wide.

Can you use joist hangers for stair stringers?

Use joist hangers to fasten the blocking. Pros: Allows for the use of all types of stair stringer hangers. The top of the stair stringer acts as the first tread instead of being flush with the deck’s surface.

How do you attach stair stringers to joists?

Stair Stringer Attachment If your first tread steps down from the deck, you must extend the rim joist to create a solid surface below the deck rim to attach it to. You should attach 2×6 or 2×8 support framing under the rim flush to the bottom of the stringer. The stairs will hang here.

How far should stair tread overhang riser?

Stairs must have an overhang between 3/4″ to 1-1/4” to increase the depth of the step, making it better for descent while maintaining a clear 10-inch going for the ascent. Treads that are 11-inches deep or greater do not require an overhang.

How thick is a stair stringer?

Stair Stringer – 3″ thick. All stair stringers are 11 1/2″ tall. Hardwood stringer boards for free standing open rise staircases are available in any thickness and overall dimensions required.

How far can a 2×12 stair stringer span?

A 2×12 stringer has a maximum unsupported span of 6 feet. These stairs (7) are likely to deflect and cause the stringers to either pull loose from the framing or shear along the grain.

What is the best stair riser height?

Rule one says that rise plus run (r+R) should equal 18 inches. Why? That’s what most people find to be a comfortable stride on most stairs. You can cheat a bit up or down, but below 17” and more than 19” will result in steps that require strides either too big or too small for most people.

Do stair stringers need support?

Yes, the stringers need to be supported along their length, but they can span a few feet too, depending on 1) the width of the stairs, 2) the number of stringers, and 3) size of riser board. 1) The wider the stair the more load will be transferred to the stringers.

What is a good rise and run for stairs?

Over the years, carpenters have determined that tread width times riser height should equal somewhere between 72 to 75 inches. On a main stair, the maximum rise should be no more than 8 1/4 inches and the minimum run should be no less than 9 inches.

Is 45 degree stairs too steep?

A standard stair has 11″ treads and 7″ risers. Using those dimensions a stair at 45° would have 7″ treads (too small) with 7″ risers or 11″ treads with 11″ risers (too big). So yes, a 45° stair is too steep and more importantly doesn’t even come close to meeting the building code.

How do you measure a staircase?

You divide the height by 7 inches; if, say, the floor-to-floor distance is 8 feet, 10 inches (or 106 inches), then you’ll need 15 treads (106 divided by 7 equals 15.14). Next, you divide the height by the number of treads (15 into 106), producing the exact tread height (7.06 inches).