Can You Build a Stair Stringer With a 2 by 8

For safety and code compliance, the riser height and tread depth must exist consistent forth the whole stair. The first course of action is always to figure out the overall rise of the stair by extending a level from the finished surface of the deck over the finished surface of the landing and measuring betwixt those two elevations.

Steps for Cutting Stair Stringers

Doing the math

Say the overall rise is 25 inches. The largest riser top at each step that virtually edifice codes allow is seven ¾ inches. Dividing 25 past 7 ¾ and rounding upward will determine the number of risers in the stair:

25 ÷ seven.75 = iii.23 = 4 risers

To find the private riser pinnacle, divide the overall rising of 25 by the number of risers:

25 ÷ 4 = 6.25

The other number you demand to lay out stringers is the tread depth, also called the run. The minimum allowed past most codes is ten inches, and that'south a proficient size to use. Making them deeper requires a longer cut to notch the stringers, which weakens them.

Selecting stringer stock

iStock

Stringers should e'er be cut from 2x12s. Notching smaller stock doesn't leave enough wood to safely carry the loads of a stair.

When ordering stringers, allow near fourteen inches of stringer length for each pace. Look for direct stock with as few knots as possible. You'll demand at least i stringer for every 16 inches of stair width. If you're using synthetic decking for the treads, some manufacturers crave stringers to be spaced no more than 12 inches apart.

Laying out the stringer

• Lay a direct piece of 2x12 on sawhorses.
• Hold a framing square with the rising dimension on the tongue and the run dimension on the blade intersecting the edge of the 2x12.
• Clamp a scrap of forest to the underside of the of the square to serve every bit a guide, and then mark out the first cutting with a pencil. The longer line is the tread cutting or run, and the shorter line is the riser.
• Motility the foursquare up the stringer, aligning the next tread cut with the top of the riser below, and mark the next tread and riser.
• Continue until you've marked out all the tread cuts and riser cuts.

Adjust the Stringer for the Tread Thickness

If you lot were to cut the bottom riser at the total summit of vi ¼ inches, placing the bottom tread would increase the top of that first stride by thickness of the that tread. If, for example, your treads are 1 inch thick, that bottom step would exist seven ¼ inches instead of the desired half-dozen ¼ inches. That's unsafe, and a code violation.

• At the top, placing the upper tread would have the opposite effect and that step would be 5 ¼ inches instead of half dozen ¼ inches. The solution is uncomplicated – shorten the lesser riser cutting on the stringer by the tread thickness. So, that cutting where the stringer meets the bottom landing would be 5 ¼ inches from the tread in a higher place, while all the other risers would remain at half dozen ¼ inches.
• Lay out this bottom cut by holding the square on the riser line and drawing a line parallel to the bottom tread.
• There volition always be one less tread than at that place are risers considering the deck itself acts as the top step. The deck framing or fascia will act as the top riser, and so the final cut on the stringer is unremarkably laid out and made square downward from the top tread, depending on how y'all plan to tie the stringers into the deck framing.
• With a circular saw, cutting out the stringer. Stop the cuts at the inner corners, and stop them with a handsaw, jigsaw, or reciprocating saw. Apply this outset stringer equally a pattern to lay out all the others.

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Tools and Materials

• Pressure treated 2x12 for stringers
• Either decking fabric or force per unit area treated 2x12 for treads
• Decking fabric for risers
• Screws for attaching treads and risers
• Stringer connectors such as Simpson LSC Adaptable Stringer Connectors

Tools

• Record mensurate
• Framing square
• Ii small clamps
• Cordless drill
• Pencil
• Circular saw
• Handsaw, jigsaw, or reciprocating saw

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Source: https://www.thisoldhouse.com/stairs/21591423/how-to-cut-stair-stringers

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