Building Stairs

Building the Stairs

Once you've determined the rise and run and installed a landing pad, you're ready to build the stairs.

Stairs have to withstand plenty of use, so choose lumber that is straight and free of knots and other defects. Pay extra for Select or No. 1 lumber. Some lumber dealers sell 2x12s specifically approved for use as treads or stringers.

If you accidentally break a step off a stringer, drill pilot holes, apply exterior grade polyurethane glue, and drive screws or nails to reattach it.

The full width of the stringers must be firmly attached to the deck framing. Usually the outside or header joist is not deep enough, so you need to install a 2x6 or 2x8 brace directly below. This may require some improvising. Build out from the beam or from the posts so that the brace is as strong as the joist above it.

Prestart Checklist

Time
Once the landing is finished and the layout calculated, four to five hours to cut and install stringers, a toe-kick, treads, risers, and rail posts for an eight-step stairway

Tools
Tape measure, level, hammer, drill, circular saw, handsaw, framing square, layout square

Skills
Cutting 2x lumber at angles, fastening with nails or screws

Prep
Complete the crossbrace, lay out and cut either end of a stringer, and install the landing

Materials
2x12 for stringers, 2x lumber or decking for treads, 2x4 toe-kick, 4x4 posts, post anchors, angle brackets, screws or nails, masonry screws

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Step 1

Test the partially cut stringer to make sure it fits between the deck and the landing with the tread lines level. With a circular saw, cut each line. Don't cut farther than the intersection of the tread and riser lines.

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Refresher Course: Notching for a toe-kick

The bottom of an inside stringer rests partly on the slab and partly on the 2x4 toe-kick. Use a circular saw and handsaw to cut a notch 1-1/2 inches high and 3-1/2 inches deep.

Step 2

Finish the cuts with a handsaw or a saber saw. Take care not to bump the resulting teeth of the stringer. Use the first stringer as a template for laying out the others.

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What If... You want a cleated stringer?

To make a closed stringer, make only one cut at the bottom and one at the top. Draw lines indicating both the bottoms and tops of the treads. Drill pilot holes and attach the tread cleats with 1-1/4-inch lag screws.

Step 3

Attach a crossbrace directly below the rim or header joist and anchor the stringers to the brace. The tops of the notched stringers (and the metal cleats on closed stringers) must line up so a tread can rest across all of them. Square the stringers to the deck with a framing square, and anchor them with angle brackets.

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Step 4

Slip a 2x4 toe-kick under the inside stringers and against the insides of the outside stringers. Drill holes through the toe-kick; then drill holes into the landing using a masonry bit. Fasten the toe-kick to the landing with bolts and anchors or masonry screws. Drill angled pilot holes and drive screws or nails to attach the stringers to the toe-kick.

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Step 5

Attach a post anchor to the landing where the post is at the full width of the stringer. Use the epoxy-and-threaded-rod method. Fasten the post to the anchor. Plumb the post and drill a hole for a carriage bolt through the post and stringer.

Be sure the carriage bolt will not interfere with the tread or tread hardware. Tap the bolt through and fasten it with a washer and nut.

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Step 6

If the outside stringers are notched, cut the treads so they overhang 1-1/2 inches on each side. If you are using closed stringers, cut treads to fit between them. Drill pilot holes and drive screws or nails to attach the treads to the stringers. Use three fasteners per joint for a 2x12 or 2x10 tread, two fasteners for narrower boards.

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