ADU Roof Cost in Los Angeles: What Homeowners Should Expect
ADU roof cost in Los Angeles runs $4,500 to $16,000 depending on size and material. What garage conversions and new builds pay, plus Title 24 rules.
Los Angeles approves more ADU permits than any other city in California, and every one of those units needs a roof over it. ADU roof cost in Los Angeles runs from about $4,500 for shingles on a garage conversion to $16,000 for standing seam metal on a new build. The price depends on what you’re starting with, the material you pick, and two state rules that catch most owners off guard. Here’s the breakdown.
What Drives ADU Roof Cost in Los Angeles
Four things set the price: roof size, material, the condition of the existing structure, and access.
Size works against you on an ADU. A typical unit has 400 to 1,200 square feet of roof area, which sounds cheap compared to a full house. But roofing crews price small jobs with minimums. Setup, tear-off disposal, permits, and cleanup cost nearly the same on a 5-square roof as a 15-square roof. So the per-square-foot rate on an ADU often runs 20 to 40 percent higher than the $5.50 to $9.50 you’d pay per foot on a full-size shingle reroof.
Access matters too. A detached unit at the back of a long narrow lot means hand-carrying material past the main house. Hillside lots in Highland Park and Eagle Rock add staging problems that flat Valley lots in Van Nuys or Reseda don’t have.
Garage Conversion vs New-Build ADU
These are two different roofing jobs, and the costs split accordingly.
Garage Conversions
Most LA garages were built between the 1940s and 1970s with 2x4 rafters, skip sheathing, and either a low-slope torch-down roof or worn-out shingles. Almost none of them meet current code for a living space.
Plan on a full tear-off, new plywood sheathing in many cases, and sometimes rafter reinforcement before any roofing goes on. If the inspector finds rot or undersized framing, structural work adds $1,500 to $4,000 on top of the roofing itself.
New-Build ADUs
A new detached unit gets a roof priced like any new construction: clean framing, no tear-off, no surprises. The cost driver here is code. New builds must meet current Title 24 energy rules and, in most cases, the state solar mandate. More on both below.
ADU Roofing Materials and Price Ranges
Here’s what each material runs installed on a typical LA ADU with 500 to 900 square feet of roof area:
- Asphalt shingles: $4,500 to $8,000. The default for pitched ADU roofs. Cool-rated colors satisfy Title 24 on steep slopes.
- Torch-down modified bitumen: $5,000 to $8,500. Common on flat garage conversions. Needs a reflective coating to meet energy code.
- TPO membrane: $6,000 to $10,000. White single-ply that meets Title 24 out of the box and lasts 20 to 30 years. Our flat roofing crew installs more TPO on ADUs than anything else.
- Standing seam metal: $8,000 to $14,000. Lightest structural load and a 40-plus year lifespan. Popular on modern prefab units.
- Concrete tile: $10,000 to $16,000. Usually chosen only to match a tile main house. The weight often requires beefed-up framing on conversions.
If your main house needs work at the same time, bundling the ADU into a full roof replacement usually beats pricing the two jobs separately. One mobilization, one permit package, one crew.
Title 24 and the Solar Mandate
Two state rules move the number more than any material choice.
First, Title 24. Los Angeles sits in a climate zone where low-slope roofs must meet cool roof reflectance standards. White TPO passes automatically. Torch-down needs a rated coating, which adds $500 to $1,200 on an ADU-sized roof. Steep-slope shingles need cool-rated colors in most cases. Our cool roof guide covers the ratings in detail.
Second, solar. California’s energy code requires solar panels on most new-construction detached ADUs. Garage conversions are exempt because the building already exists. Shaded lots and very small roofs can qualify for exceptions, but budget $8,000 to $15,000 for a small compliant system if your new build doesn’t. Plan the roof and the panels together so nobody drills through a brand-new membrane six months later.
What a Realistic ADU Roof Estimate Should Include
A real bid spells out every line. On an ADU, look for:
- Tear-off and disposal of the old roofing, with a price per layer
- Sheathing replacement priced per sheet, since old garages almost always need some
- Underlayment type, not just “felt”
- Flashing at every wall the ADU shares or faces, plus any skylights
- The cool roof coating or rated material that satisfies Title 24
- Permit fees and who pulls the permit
- Gutters and downspouts, which most old garages never had
A bid that just says “reroof garage, $6,000” tells you nothing. The cheap number usually means the sheathing surprise becomes your problem at mid-project.
How LA Compares to National Averages
Nationally, a small outbuilding roof might run $3,000 to $5,500. LA lands 30 to 50 percent above that. Labor rates here are among the highest in the country, disposal fees are steep, and the energy code adds material requirements most states don’t have.
Permits add a few hundred dollars as well. A standalone garage reroof goes through LADBS like any other job, and our roof permit guide walks through the process and fees. If the roof work is part of the ADU conversion itself, it folds into the main building permit instead.
Frequently Asked Questions
How much does it cost to reroof a garage before converting it to an ADU?
Most garage reroofs in LA run $4,500 to $8,500 including tear-off and new sheathing where needed. Add $1,500 to $4,000 if the framing needs reinforcement to pass inspection.
Does a new ADU need solar panels in Los Angeles?
Usually yes. The state energy code requires solar on most new-construction detached ADUs. Conversions of existing garages are exempt, and heavily shaded lots can apply for an exception.
Does my ADU roof have to match my main house?
Not by city rule in most neighborhoods. Historic Preservation Overlay Zones are the exception, where materials and colors face review. Outside HPOZ areas, matching is your call, though it helps resale.
Do I need a separate permit to reroof a detached garage?
Yes, if the reroof happens on its own. It runs through LADBS like any reroof, typically a few hundred dollars. If the roofing is part of your ADU conversion permit, it’s covered under that scope instead.
What’s the cheapest roof that passes Title 24 on a flat ADU?
Torch-down modified bitumen with a rated reflective coating is usually the lowest upfront number. TPO costs $1,000 to $2,500 more on an ADU but lasts longer and skips the recoating cycle, so it often wins on total cost.
Get a Real Number for Your ADU
An ADU roof in Los Angeles runs $4,500 to $16,000 depending on the structure, the material, and the code rules that apply to your project. The biggest cost surprises hide in old garage framing, so get the roof assessed before your conversion budget is locked. A roof inspection before you finalize plans tells you exactly what the structure needs. Call Best LA Roofing at (818) 446-6122 for a free estimate on your ADU roof.