ADUs and additions, Altadena, Los Angeles County

Altadena ADUs Planned for Sun, Wind and Storms

Planning an Altadena ADU for strong sun, dry wind and heavy storms, with ember-resistant details where mapped and a Los Angeles County permit path.

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Near the mountains, a small building has to deal with strong sun, dry wind that can carry embers and now and then a storm that sends a rush of water off the roof at once. Our Altadena ADU plans start from those general conditions. Each unit type is then tested against the parcel, state ADU law and county zoning, with a backyard build and a JADU carved from the house weighed on equal terms.

Shell choices for embers, sun and storms

Some Altadena parcels lie in mapped fire hazard zones, and a new unit on one may need to meet ember-resistance rules. For that case the drawings call for a Class A roof assembly, vents fitted with fine metal mesh, closed soffits, tempered multipane windows and exterior cladding that will not burn. Against strong sun we specify a reflective roof surface, deep attic insulation and shade over glass that takes the late-day sun. Gutters are sized generously and each downspout runs to a planned discharge point clear of the footings. If the lot slopes, a drainage plan keeps roof water from collecting against the new walls or the main house.

Permits through Los Angeles County

Altadena is unincorporated, so Los Angeles County issues the permit. Building and Safety at County Public Works reviews the ADU drawings and sends inspectors during construction, and on a mapped parcel the county fire department may weigh in on access and brush clearance. Comments arrive in rounds and each one is answered on revised sheets, with the fire details and drainage layout kept in the same set. Inspections follow the build from footings through framing and insulation to the final, and the unit may be occupied once the county signs that last visit.

What we build in Altadena

Second units and room additions lead, with the rest of our services available on the same lot.

Cities close by

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