Room Additions in Santa Monica
73.4% of housing units in the City of Santa Monica were built before 1980 (Census 2020–2024), so older-home checks matter for your addition.
Santa Monica at a glance
- Share of housing units built before 1980, City of Santa Monica, 2020–2024
- 73.4%
- Median year structure built, City of Santa Monica, 2020–2024
- 1968
- Share of occupied housing units that are owner-occupied, City of Santa Monica, 2020–2024
- 27.9%
U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates · data as of
- Numbers from US Census public records
- Up to three local contractors, never a long list
- Free, no obligation
What do permits say a room addition costs?
From City of LA building permits, last 12 months. Not a contract price. How we calculate this
Declared values on City of Los Angeles building permits, last 12 months. The dataset covers the City of Los Angeles only, so treat it as a regional reference for Santa Monica. A declared value is what the permit states, not your contract price. How we calculate this.
Source: LA Department of Building and Safety, Building Permits Issued 2020 to Present (data.lacity.org), permits on one- and two-family homes issued to ; fire rebuilds excluded. ZIP medians need 20+ permits.
Santa Monica housing facts (Census, 2020–2024)
Planning your project
Most homes in Santa Monica are older. The U.S. Census Bureau estimates that 73.4% of housing units in the City of Santa Monica were built before 1980, and the median year built is 1968 (2020–2024). For a room addition, that means the existing house is part of the plan from the start.
What Santa Monica's homes mean for your room addition
An older house may need checks before framing starts. Ask the builder how the foundation is bolted and braced, and how new framing will tie into it. Check electrical panel capacity, since a new room adds load. Homes built before 1978 may have lead-based paint, and old walls can contain asbestos, so plan for testing when walls are opened. An older roof and exterior can also be hard to match.
These are things to check, not certainties for every house. Your builder can tell you what applies to your home.
Only 27.9% of occupied housing units in the City of Santa Monica are owner-occupied (2020–2024), so many homes here are rented. If you own a rental, plan for tenants: keep them informed and schedule noisy work around them. The median value of owner-occupied homes in the City of Santa Monica is $1,755,500 (2020–2024). Use that figure only to judge how much to put into your home relative to its value.
The typical path for a room addition in Santa Monica
The typical path for a room addition in Santa Monica
Check what your lot allows
Confirm setbacks, height and lot coverage with the City of Santa Monica before you design. Ask whether any other rules apply to your property.
Design and engineering
Draw the addition and have the structure engineered. Ask how the new framing will connect to the existing foundation and walls.
Plan check and permit
The city reviews your plans before a permit is issued. Expect review comments and revisions, and do not assume a set approval timing.
Foundation and framing with inspections
Inspections happen at key stages. In an older house, confirm that foundation bolting and bracing are addressed in the plans.
Roofing, mechanical, electrical and plumbing rough-in
Check panel capacity, plan for lead and asbestos testing where old walls will be opened, and schedule the rough-in inspections.
Finishes
Install drywall, flooring, paint and fixtures. Keep dust and debris contained from the rest of the home where you can.
Final inspection
Once the city signs off, the room is ready to use. Keep your permit and inspection records for future sales or refinancing.
Questions about room additions in Santa Monica
Does an older Santa Monica home need extra checks for an addition?
Often, yes. The U.S. Census Bureau estimates that 73.4% of housing units in the City of Santa Monica were built before 1980 (2020–2024), and the median year built is 1968. Ask about foundation bolting and bracing, electrical panel capacity, and testing for lead-based paint and asbestos where old walls will be opened.
What should I think about if I rent out my Santa Monica home?
Only 27.9% of occupied housing units in the City of Santa Monica are owner-occupied (2020–2024), so renting is common here. If you rent out a property, tell your tenants about the work early, keep them informed, and schedule noisy work around them. Ask your builder how the schedule will affect them.
How should I weigh my budget against home value?
The median value of owner-occupied homes in the City of Santa Monica is $1,755,500 (2020–2024). Use it only as a general frame: think about how much you want to put into your house relative to what it is worth. This guide does not give cost figures for Santa Monica.
How can I check a contractor's license status?
You can check any contractor's license status with the CSLB (Contractors State License Board). Ask the builder for its license number and check it yourself before you sign anything.
What is the first step for a room addition?
Start by checking what your lot allows with the City of Santa Monica. Then request a free estimate from a local builder, and bring your plans and your questions about older-home checks.
Recent work by a contractor in our network
Photos from the contractor's own projects, used with permission. Captions name the type of work.
Whole-home remodel, exterior 
Kitchen, whole-home remodel 
Addition / ADU interior 
Addition / ADU interior 
Whole-home remodel 
Whole-home remodel
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