Residential New Single Family, Duplex or ADU Checklist

What to include on a residential site plan

Specific to ADU:

• Locate separate Water Heater and HVAC equipment in the Accessory Dwelling Unit or in common areas accessible to all residents
• Locate water and gas line shut off
• Locate electrical panel and label it as new service or subpanel. If utilizing a subpanel, upload a load calculation from an electrician to the documents folder in ePlans

Floor plan details to include based on design:

• Water heater anchoring
• Stair and handrail
• Guard rail and post attachment
• Window wells
• Egress windows
• Insulated headers
• Deck details
• Ramps
• Tested assembly detail when fire and/or sound rating is required.

• Locate all continuous footings, spread footings, basement retaining walls, and pony walls
• Indicate footing sizes, anchor bolt size and spacing
• Locate and identify all hold downs and their capacities
• Locate all crawl space vents and include their size
• If crawl space vents cannot be spaced evenly on a minimum of three sides of the crawl space, or do not provide enough ventilation per code, locate a continuously operated mechanical exhaust fan with a minimum of 1 CFM for every 50 square feet of crawl space
• Provide radon mitigation layout
• Locate and dimension crawl space access and access through pony walls

Foundation details to include based on design:

• Typical foundation wall
• Typical slab foundations
• Stepped footing
• Post and beam
• Radon mitigation details
• Basement retaining wall (engineering required, obtain detail from Engineer of Record)
• Prescriptive patio cover footing (one of two options must be used unless designed by an Engineer)
• Protection Against Decay

• Include size, spacing, and span for all framing members
• For wood framing, include the species and grade of framing members
• Include bearing locations for all framing members including stairs
• For engineered framing products such as I-joists, include calculations and a layout diagram from the manufacturer
• Include location and framing for crawl space access

• Include size, spacing, and span for all framing members
• For wood framing, include the species and grade of framing members
• Include bearing locations for all framing members
• For manufactured trusses, include calculations prepared by a licensed Washington State Engineer and a layout diagram from the manufacturer

• Include all ridge lines and valleys
• Include location of all attic vents
• Include all roof overhangs with their dimensions
• Include the slope of the roof, sheathing type and thickness, and roof covering material

Roof details to include based on design:

• Gable end bracing for trusses and truss or rafter uplift connection

• Dimension story height, ceiling height, and total height of the structure
• Include Room identification
• Include all interior walls
• Locate fire-resistance rated wall and floor/ceiling assemblies if utilized
• Indicate the size and spacing of structural members such as beams, joists, studs, and rafters along with their spacing
• Indicate the connection of floor joists to the wall framing at upper levels and the connection of roof rafters to double top plates
• Indicate proposed minimum insulation R-values and maximum U-factors for each exterior element. (Roof, above and below grade walls, floor, doors, and windows)

Wall section details to include for fire-resistance rated assembly:

• Townhouse separation
• Townhouse separation continuity
• Townhouse two-one-hour walls with parallel framing
• Townhouse two-one-hour walls with perpendicular Framing
• Duplex one-hour wall with perpendicular framing

• Indicate all braced wall lines
• Locate and dimension all wood structural panels, Alternate braced wall panels, portal frames etc.
• Locate all windows and doors
• Upload the APA Wall Bracing Calculator to the documents folder in ePlans (See resources for a link to the APA Wall Bracing Calculator)

Bracing details to include based on design:

• Braced wall panel methods
• Exterior brace wall lines at corners
• Braced wall panel method 1&2
• Portal frame
• Continuous sheathing portal frame
• Alternate braced wall panel with hold downs
• Cantilever brace wall connection

• Provide elevation drawings for all four sides of the home
• Include accurate grade lines
• Include lines representing finished floor levels
• Dimension wall height for each story
• Dimension building height, measured from average grade to average roof peak