🔧 STRUCTURAL FIRE PIT SEATING RING

(Bolted Segment System — Load Rated)

📐 Final Locked Dimensions

• Fire pit diameter: 36"
• Safe clearance from flame: 30"
• Inside bench diameter: 96"
• Outside bench diameter: 120"
• Segment count: 8
• Angle per segment: 45°
• Mitre cut per side: 22.5°
• Seat height: 18"
• Seat depth: 18"
• Segment face width (front edge): ~36."

🪵 Materials List

Pressure-Treated Lumber Recommended

• (16) 2×4 × 8' boards (frame construction)
• (16–20) 2×6 × 8' boards (seat boards)
• (16) 4×4 blocks (leg posts, 16–18" height)

Hardware (Exterior-Rated / Galvanized)

• (16) ½" × 5" galvanized carriage bolts (segment connections)
• Washers + lock nuts
• 3" exterior structural screws
• 2½" exterior deck screws
• Optional galvanized corner brackets (interior frame reinforcement)

🛠 Tools Required

• Mitre saw (set to 22.5°)
• Drill/driver
• ½" drill bit
• Socket wrench
• Tape measure
• Clamps
• Speed square

📏 Cut List (Per Segment)

Multiply by 8 for a full ring.

Frame

• (2) 2×4 front/back rails — 36" (22.5° on both ends)
• (2) 2×4 side rails — 18"
• (2) 2×4 internal braces — 16"
• (2) 4×4 legs — 16–18"

Seat

• (2–3) 2×6 seat boards — 36" (22.5° cuts both ends)

🔨 Step-By-Step Build

1️⃣ Build Individual Segments

Cut all front and back rails at 22.5° on each side.

This creates the 45° segment geometry.

Assemble the rectangular frame using 3" exterior screws.

Install two internal braces for load distribution.

Attach 4×4 legs flush with outer corners.

Each segment should feel rigid before connection.

2️⃣ Install Seat Boards

Attach 2×6 boards across the frame.

Leave ¼" spacing between boards for drainage.

Secure with 2½" deck screws.

3️⃣ Connect Segments

Align two segments together.

Drill ½" holes through side rails.

Install:

• ½" galvanized carriage bolts
• Washers
• Lock nuts

Repeat for all connections.

This creates a rigid circular structure while allowing future disassembly.

🧠 Structural Explanation

Each segment is designed to support:

≈ 400 lbs minimum (two adults).

With 8 segments:

Total distributed seating capacity exceeds 2,500 lbs when the weight is evenly distributed.

Why Bolts Matter

Carriage bolts resist shear forces when people lean sideways.

Screws alone are not sufficient for lateral movement resistance in a circular system.

Why 30" Clearance Matters

Wood near flame requires airflow and distance.

30" clearance:

• Reduces heat exposure • Improves comfort • Preserves lumber longevity

🔥 Heat & Material Considerations

• Always use pressure-treated or exterior-rated lumber
• Maintain flame containment within the fire ring
• Avoid direct flame contact
• Inspect hardware annually

💰 Estimated Cost Breakdown

Pressure-treated lumber: $250–350 Galvanized hardware: $80–120 Fire pit (if needed): separate

Estimated total bench build: $330–470

(Varies by region.)

🧰 Recommended Tools & Materials

• Pressure-treated 2×4 lumber
• Pressure-treated 2×6 boards
• 4×4 posts
• ½" galvanized carriage bolts
• Exterior structural screws
• Exterior deck screws
• Miter saw
• Cordless drill
• ½" drill bit
• Clamps