Building in Altadena: what to know first
Projects in Altadena
- Remodels and additions for older Craftsman and mid-century homes
- ADUs and garage conversions
- New home construction and rebuilds
- Retaining walls, drainage and grading on sloped lots
- Roofing, fencing and exterior work built to foothill fire-safety expectations
Unincorporated Los Angeles County
Because Altadena is unincorporated, projects are reviewed by Los Angeles County departments, such as Regional Planning and Public Works, instead of a city building department. Following the 2025 Eaton Fire, the county set up an Altadena One-Stop Recovery Permitting Center to consolidate review for rebuilding projects. Programs, timelines and requirements change, so we confirm the current process for your property.
If you are rebuilding
Rebuilding a home is a hard personal process as well as a construction one. We can help with design, permit preparation and construction planning. We do not advise on insurance claims, financing or assistance programs, and we encourage you to work with qualified professionals there.
Foothill conditions
Altadena's north end rises toward the San Gabriel Mountains. Fire-hazard standards, slopes, drainage and access can all affect design and cost. Exterior materials, vents and roofing are chosen with those standards in mind.
Gather your documents early
If you are planning a rebuild or major project, gather your existing documents early, such as prior plans, surveys and photographs. They can save time during design and permit review.
Local resources for Altadena homeowners
Official and community sources worth bookmarking before you plan a project:
- LA County Regional Planning — Zoning and land-use review for unincorporated areas.
- LA County Public Works — Building and safety services for unincorporated areas.
- Altadena Heritage — Community organization focused on Altadena's history and architecture.
- Angeles National Forest — The mountain landscape bordering Altadena.




