Build the 36" guardrails, install stairs down to grade, and optionally add benches.
Guardrails 36" tall minimum. Balusters spaced so a 4" sphere cannot pass through. Handrails required on stairs with 4+ risers.
⚠ MATERIALS NOT YET PURCHASED FOR THIS PHASE: The railing lumber (4x4 posts, 2x6 caps, 2x4 rails) is on hand from Order #1, but as of Aug 2026 nothing else is: no balusters (~130 needed — not on either invoice), no guard-post carriage bolts (40 needed — 4 per post per A3.2, not 2), no #8 baluster screws, no 3" structural screws, no LSCZ stringer hangers, no stair-rail 2x4s. See the Hardware Swap List for the full shopping list before starting this phase.
⚠ POOL CODE — settle before building rails: This deck serves an above-ground pool. CT jurisdictions commonly require the stair to have a self-closing, self-latching gate (latch 54" up), and some require 48" barrier height rather than 36". Confirm with the building department whether 36" rails + a gate satisfy the pool barrier code before cutting posts to 36" — retrofitting taller rails is expensive. (Also flagged in the verification doc inspector list.)
Section 1: 36" Guardrails (per A3.2)
4x4 posts every 6' max, through-bolted to the rim joist with 4 carriage bolts each (2 pairs, per A3.2 Railing Post note). 2x6 cap, 2x4 top and bottom rails, 2x2 balusters at <4" spacing. Balusters attached with 2 × #8 screws top and bottom per A3.2 detail 03. (Diagram shows 2 of the 4 bolts — the other pair sits beside them.)
Component
Material
Details
Rail posts
4x4 PT
Every 6' max, bolted to rim joist
Top rail
2x6 PT (cap) + 2x4 (sub-rail)
36" above deck surface
Bottom rail
2x4 PT
~4" above deck surface
Balusters
2x2 PT or metal
< 4" spacing
Materials
Item
Quantity
Notes
4x4 PT posts
~8-10
Perimeter every 6' max
2x6 PT cap rail
Perimeter length
Top cap
2x4 PT rails
2 × perimeter length
Top and bottom horizontals
2x2 PT balusters
~130 (~45 pcs 2x2x8', 3 balusters each)
NEED TO BUY — not on either invoice. ~112 for deck rail + ~15-18 for stair rail. Alternative: DecksGo Snap'n Lock aluminum kits (11 deck + 3 stair)
NEED TO BUY — 4 per rail post × ~10 posts per A3.2 Railing Post note ("4 - 1/2" DIAMETER X 6" LONG (MIN.) BOLTS")
#8 exterior wood screws 2-1/2"
5 lb box
NEED TO BUY — baluster and rail attachment (A3.2 detail 03)
3" structural screws
1 lb
NEED TO BUY — rail assembly, cap, treads
Guardrail Steps
1Layout rail post positions around perimeter.
Post at each corner
Additional posts every 6' along each side
Skip the stair opening
2Bolt each 4x4 guard post to the rim joist (or the outermost joist).
Position the 4x4 vertically against the outside face of the rim joist
Post extends DOWN alongside the rim about 8-10" (below the deck framing)
Post extends UP 36" above the deck surface
Per A3.2 Railing Post note: Four 1/2" x 6-1/2" carriage bolts through the post and rim/joist (the plan calls for 4 bolts per 4x4 railing post; 1/2" × 6" minimum length — 6-1/2" gives comfortable thread engagement through 5" of wood)
Bolt positions: 2 pairs — upper pair 2" from top of rim, lower pair 2" from bottom of rim (~3-1/4" apart vertically), pairs spaced ~1-1/2" apart horizontally, all centered on the 4x4 with at least 1" of edge distance
Carriage bolt heads on the OUTSIDE face of the post; washers and nuts on the INSIDE (behind the rim)
Verify plumb in both directions before final tightening
3Cut posts to length so tops are 36" above deck surface.
4Install top and bottom 2x4 rails between posts.
Bottom rail: 2-4" above deck surface
Top rail: top edge ~1/2" below the post tops (~35-1/2" above deck). The 1-1/2"-thick 2x6 cap then sits on the post tops, putting the cap top at ~37-1/2" — comfortably above the 36" minimum
Structural screws through post into rail
5Install 2x2 balusters between top and bottom rails.
For 2x2 balusters (1-1/2" wide), space 4-1/2" OC (leaves 3" gap)
Toe-nail or use hidden fasteners
6Install 2x6 cap rail on top.
Set 2x6 flat on top of posts
Screw down through cap into each post
Mitered 45° cuts at corners
4" ball test: A 4" sphere should NOT pass through any opening. Most-cited code violation on decks.
Section 2: Stairs (per A3.3)
Component
Material
Details
Stringers
2x12 PT
Max 6' span per A3.3 (we have 2x12x10' — better than plan's 2x10 minimum)
Rise (per step)
—
7-3/4" MAX per A3.3
Run (tread depth)
—
10" MIN per A3.3
Nosing overhang
—
3/4" MIN to 1-1/4" MAX per A3.3
Tread
Two 2x6 PT per tread (from the 12 pcs 2x6x16 on Order #2)
5-1/2" + 5-1/2" + small gap ≈ 11-1/4" — same coverage as a 2x12. (The 2x12x10s are all consumed by stringers; buy 3× 2x12x8 instead if you prefer single-board treads. Trex treads would need stringers at 12" OC or less, so stick with wood at 18" spacing.)
Risers
One 2x6 PT per riser opening (same Order #2 stock)
Required, was missing from earlier drafts: stairs more than 30" above grade may not have openings that pass a 4" sphere. A 5-1/2" board in each 7-3/4" opening leaves ~2-1/4" — passes.
Stair guardrail height
—
34" MIN measured from tread nosing to top of cap rail per A3.3
Stair Calculations
Number of risers = Total rise ÷ 7-3/4" (round UP to whole number)
Actual rise per step = Total rise ÷ number of risers
7 risers × 7-3/4" = 54-1/4" total rise. 6 treads × 10" run = 5'-0" total horizontal projection. 2x12 tread (11-1/4" actual) with 10" run gives 1-1/4" nosing = code-compliant (3/4"-1-1/4" per A3.3). 5'-0" horizontal is under 6'-0" max, so no midspan support needed.
Example — for our deck at ~54-1/4" above grade at the stair location:
Number of risers: 54.25" ÷ 7.75" = 7.0 → 7 risers
Actual rise per step: 54.25" ÷ 7 = 7.75" per step (right at code max — verify actual grade at the stair location first; if grade is 52", you get 7.43" per step which is more comfortable)
Number of treads: risers − 1 = 6 treads (the top step is the deck itself, not a tread)
Using 10" run per step (matches 2x12 tread with 1-1/4" nosing): total horizontal run = 6 × 10" = 60" (5'-0")
60" horizontal span is under the 6'-0" MAX per A3.3 — no intermediate 4x4 support post needed
Actual stringer length (angled): about 82" — well within the 2x12x10' pieces on hand
If actual grade is slightly higher (say 52" total rise), you get more comfortable steps: 52 ÷ 7 = 7.43" per step. Measure grade at the exact stair location before committing.
Stair Steps
1Calculate rise and run based on deck height at stair location.
Measure from top of deck (finished decking surface) down to finished grade at the stair landing
Divide that measurement by 7-3/4"; round UP to a whole number to get riser count
Actual rise per step = total measurement ÷ that riser count
2Layout stringer on 2x12 PT.
Use a framing square with stair gauges (small brass buttons) set at your rise (e.g., 7-3/4") and run (10" — see stair calculations above for why 10" not 11")
Mark each step's rise and run along one edge of the 2x12
Cut with circular saw along the marks; finish the inside corners of the cuts with a handsaw (don't over-cut with the circular saw)
3Install stringer against deck rim.
Top attaches to the rim joist using a Simpson LSCZ sloped joist hanger (625 lb min capacity per A3.3)
Bottom sits on a concrete pad, patio block, or 2x6 base at grade
Plan A3.3 requires stringers MAX 18" apart. For a 36" wide stair, that's 3 stringers (at 0", 18", 36"). For 48" wide, 4 stringers. Never wider than 18" between stringers.
4Install riser boards, then treads.
Riser boards first: screw one 2x6 across each riser face (7 total), tight under the tread nose position — this closes the open risers so a 4" sphere can't pass (required when the stair is more than 30" up, which this one is at ~54")
Treads: two 2x6 PT per tread (5-1/2" + 5-1/2" + gap ≈ 11-1/4" of depth) — cut from the 2x6x16 stock on Order #2
Cut treads and risers to stair width (36-48")
Structural screws through top into stringer (2 per stringer per tread board)
Predrill within 2" of ends to prevent splitting
Front tread board projects past the riser face by 1-1/4" (the "nosing")
5Install stair guardrails matching deck rails.
Rail posts at top and bottom of stairs
Rails parallel to stair slope
34" vertical above tread nosing
Balusters at < 4" spacing
6Install pool-access gate at the stairs (if required — verify with inspector).
Self-closing, self-latching gate at the top or bottom of the stairs, opening AWAY from the pool
Latch release typically must be 54" above the walking surface
Buy a gate kit (hinges + latch, e.g. D&D TruClose + MagnaLatch) and build the gate frame from leftover 2x4 + 2x2 balusters to match the rails
Section 3: Benches (per A3.5 - Optional)
Component
Material
Details per A3.5
Bench top boards
2x4 PT
1/4" gaps between boards
Bench edge finish
2x4 PT
Around perimeter of seat
Cross support
2x4 PT
Under seat, spanning legs
Support legs
2x6 PT
Bench legs
Base
2x2 PT
At foot of legs
Bench width
—
1'-5 3/4" (17-3/4")
Bench height (seat top above deck)
—
1'-4" (16")
Corner bench angle (optional)
—
45° miter
Bench Steps
1Layout bench positions.
Typical: along one edge
At least 18" from deck edge for seating clearance
2Attach 2x6 bench support legs per A3.5.
Legs 16" tall (per plan A3.5 — measured from deck top to seat top)
Support legs from 2x6 lumber, bolted through decking into joists below with structural screws
3Install bench frame and seat per A3.5.
2x4 cross supports connect legs at seat level
2x4 top boards laid across cross supports with 1/4" gaps between boards
2x4 edge finish around seat perimeter
2x2 base at foot of legs
Bench overall width: 1'-5 3/4"
Completion Checklist
36" guardrails installed around entire deck perimeter
4x4 posts bolted to rim joist with 1/2" carriage bolts (4 per post, per A3.2 Railing Post note)
Top and bottom 2x4 rails between posts
2x2 balusters at < 4" spacing (passes 4" ball test)
2x6 cap rail installed with mitered corners
Stairs installed with 2x12 PT stringers (horizontal span under 6')
Stair rise ≤ 7-3/4" (equal on every step), run 10", treads 2× 2x6 per step with 1-1/4" nosing
Riser boards installed — no stair opening passes a 4" sphere
Stair guardrails matching deck rails, 34" min above tread nosing
Self-closing, self-latching gate installed if required by pool barrier code (verify with inspector)
Optional benches installed
Final Deck Completion Check
All framing complete, plumb, secure
Trex decking with proper gaps and fasteners
Guardrails 36" tall around all edges
Stair rails installed
All bolts and screws tight
No sharp edges or protruding fasteners
Final inspection scheduled
Common Problems & Fixes
Guardrail feels wobbly
Verify all 4 bolts per post through rim joist are snug. Add diagonal knee braces to rim.
Balusters don't pass 4" test
Space closer. 4-1/2" OC for 2x2 balusters gives 3" gap.
Stair rise inconsistent
Actual rise must be equal (max 3/8" variation). Recalculate stringer layout.
Cap rail mitered corner has gap
Recheck 45° angle. Use exterior wood filler or caulk if gaps persist.