Protecting Your ADU From Above: The Roofing Phase
The roof is one of the most critical components of your ADU. It protects everything below from rain, sun, wind, and temperature extremes. Getting it right means decades of worry-free protection; getting it wrong means leaks, damage, and expensive repairs.
Roofing Materials for ADUs
Asphalt/Composition Shingles (Most Popular)
- 25-30 year lifespan
- Costs vary — contact us for a detailed quote
- Wide variety of colors and styles
- Easy to match existing home's roof
- Best for pitched roofs (4:12 slope or greater)
Standing Seam Metal
- 40-70 year lifespan
- Costs vary — contact us for a detailed quote
- Modern, clean look popular for contemporary ADUs
- Excellent for solar panel integration
- Fire-resistant (important in wildfire zones)
Flat/Low-Slope Roofing (TPO, Modified Bitumen)
- 20-30 year lifespan
- Costs vary — contact us for a detailed quote
- Required for flat or low-slope roof designs
- TPO (white membrane) reflects heat — good for energy efficiency
- Modified bitumen is a tried-and-true option for flat roofs
Concrete/Clay Tile
- 50-100 year lifespan
- Costs vary — contact us for a detailed quote
- Classic Southern California Mediterranean look
- Very heavy — requires engineered roof structure
- Best for matching Spanish-style homes
The Roofing Process
Step 1: Sheathing Inspection
Before roofing begins, the plywood or OSB sheathing (installed during framing) is inspected for proper nailing pattern and structural adequacy.
Step 2: Underlayment
A waterproof membrane (synthetic felt or self-adhering membrane) is applied over the sheathing. This is your secondary water barrier if a shingle ever fails.
Step 3: Flashing
Metal flashing is installed at every transition point:
- Roof-to-wall connections
- Around plumbing vents
- At valleys where roof planes meet
- At eaves and rakes (drip edge)
Flashing is the #1 source of roof leaks when done poorly.
Step 4: Roofing Material Installation
- Shingles are installed from the bottom up, overlapping each row
- Metal panels are secured with concealed fasteners
- Flat roofing is adhered or mechanically attached
Step 5: Ridge and Hip Caps
Special ridge cap shingles or metal trim is installed at the peak and hips of the roof.
Step 6: Final Inspection
The city inspector verifies the roofing meets code requirements and manufacturer specifications.
Solar Panel Considerations
Under California's Title 24, most new ADUs require solar panels. During roofing, plan for:
- Roof orientation: South-facing is ideal for solar production
- Structural capacity: Solar panels add 3-5 pounds per square foot
- Conduit routing: Electrical conduit from roof to panel location
- Mounting systems: Rails and attachments should be installed with the roofing to prevent future penetrations
Budget
Roofing for an ADU requires a property-specific written estimate depending on the material, roof size, and complexity.
Coming Up Next
Day 13: Bathroom Tile & Shower — creating a beautiful, waterproof bathroom with tile work that lasts.
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Vision ADU's roofing crews deliver watertight installations on every project. Start your ADU journey.
Related Vision ADU Resources
- How to Build an ADU, Day 14: Flooring
- How to Build an ADU, Day 15: Cabinets & Countertops
- How to Build an ADU, Day 16: Paint & Finishes
- How to Build an ADU, Day 17: Final Inspection & Keys
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