16'x20' Garage Building Information and Structural Details
Building Information
Garage Dimensions: 16' x 20'
Ceiling Height: 9'-5"
Plate Height: 109 1/8"
Foundation Type: Concrete slab-on-grade with anchor bolts.
Wall Framing: 2x6 studs at 16" O.C. with OSB sheathing.
Roof Framing: Trusses at 24” O.C. with a 6/12 pitch.
Foundation & Structural Details
1. Foundation
Foundation bolts: 5/8" x 10" anchor bolts @ 4' O.C. with 7" embedment.
Footing Depth: Minimum 12" below grade.
Curb/Foundation Wall Clearance: 8" minimum above grade.
Rebar Reinforcement: #4 rebar horizontal @ 18” O.C., 2 continuous bars.
2. Shear Wall Layout
Front Wall (Garage Door Side):
Two Narrow Shear Walls at each side of the 16' opening.
Reinforced with HDU8 or HHDQ8 Hold-Downs.
Minimum 4:1 aspect ratio for shear panel stability.
Side Walls (Left & Right):
Full-length shear walls for lateral stability.
OSB/Plywood Sheathing (7/16” minimum).
8d nails, 4” O.C. on edges, 6” O.C. in the field.
Rear Wall:
Standard plywood shear wall.
3. Roof Framing ( HIP)
Trusses: Spaced 24” O.C.
Ridge Height: 13’-6”
Roof Pitch: 6/12
Sheathing: 7/16” OSB
Hurricane Ties: Simpson H2.5A or equivalent at every truss-to-wall connection.
4. Windows & Doors
Garage Door: 16’ x 8’
Side Entry Door: 3'0" x 6'8" RH Hinged
Windows: Double-glazed, Low-E
5. Insulation Requirements
Walls: R-19 to R-21
Attic: R-40
Floors: R-15 to R-38 (if applicable)
Additional Code Compliance
Seismic & Wind Load: Must comply with Mason County, WA building codes.
GFCI Protection: Required in bathrooms, kitchens, and garage per NEC 2023.
Smoke Detectors: One per room, interconnected with backup battery.
Ventilation: Bath and utility rooms vented to exterior (5 air exchanges per hour).
Tempered Glass: Required for glazing near doors, showers, and stair landings.
This document provides detailed specifications for the construction of a 16'x20' garage ensuring compliance with local building codes and structural stability.