4 easy steps to building wraparound deck stairs

Published: July 24, 2020

close-up of wraparound stairs on a deck Photo by Derek McNaughton

How many times have you sat on a deck and looked across the lake—only to see the railing instead of the horizon? On many low decks, a set of steps on all sides can eliminate the need for a railing altogether. Angled, “wraparound” stairs improve access and better integrate deck with land. And softening a deck corner with two 45° angles, instead of one 90°, isn’t that difficult for anyone with a good mitre saw, a square, some basic carpentry skills, and the know-how to cut stringers from 2x12s.

illustration of wide stairs
Illustration by Jacques Perrault

1. Map out your stringers
How many stringers you need depends on the treads. For 2×6 tread boards, which are sturdier than 5/4 deck boards, space stringers 16″ on centre. After cutting the stringers, usually with a 7″ rise over 11″ run, place them against the deck’s rim joist. Fastidiously check that the treads will be level—both perpendicular to the deck and between each stringer. Pencil mark each stringer’s location.

2. Firm up your base
I apply PL Premium Fast Grab construction adhesive to the stringer where it meets the rim joist, set it in position, and, from the back of the rim joist, drive three GRK structural screws (5/16″ x 4″) through the joist into each stringer. These code-compliant screws aren’t cheap, but they fasten as firmly as lag bolts. Wipe away any excess adhesive, keeping it off your bare hands—otherwise, only time will remove it.

3. Fill in the gaps
Where the rim joists meet at 45°, place a stringer on each side, as close to the corner as possible. Add blocking to bridge any large spaces between these stringers and to support treads. Each tread will need to be cut at 22.5° where it meets the next board. Same with the risers. Dry fit treads on the stringers: where the boards intersect is where they’ll be cut. Mark with a pencil, set the mitre saw to 22.5°‚ and sever. Anywhere you make a fresh cut—on stringers, treads, risers, whatever—coat with wood preservative to prevent rot. I use 3″ deck screws to secure the risers and treads to the stringers, with PL on all the joints too.

4. Mind the code
Railings are a code requirement for any deck higher than 24″ in most Canadian jurisdictions. For decks with more than three steps, some building codes require handrails too; as always, check with your municipality before you start building.

Pro tips

  • Reinforcing joints with extra-strength construction adhesive adds rigidity to stairs
  • Using blocks helps support the treads at the 45° corners
  • These wide stairs can double as bleacher-style seating

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