Residential construction · Los Angeles
Room Addition
Room addition refers to the process of adding an additional room or rooms to an existing structure. This could involve adding an extension to the side or back of a house, or converting an existing space such as a garage or attic into a living space.
What to expect
Our Room Addition process
A clear view of the steps helps you prepare questions and understand how your project moves forward.
- 01
Room additions are often done to accommodate growing families, to create additional living space, or to increase the value of a property.
- 02
Room additions can be a complex and expensive undertaking, and it is important to work with a licensed contractor and obtain the necessary permits and approvals from the local government.
- 03
The process may involve structural modifications, electrical and plumbing work, and other aspects of construction that require professional expertise.
Common questions
Frequently asked questions
How long does a room addition take in Los Angeles?
A standard room addition in LA takes 3–6 months from permit approval to completion. Timeline depends on size, structural complexity, and permit processing speed at your local building department. KM Builders manages the full timeline and keeps you updated weekly.
What does a room addition cost in Los Angeles?
Room additions in LA typically cost $80,000–$200,000+ depending on size, foundation type, and finishes. A basic bedroom addition runs $90–$150 per square foot. Additions over living space (second story) cost more than ground-floor slab additions.
Do I need permits for a room addition in LA?
Yes, all room additions in Los Angeles require building permits. The City of LA Building & Safety (LADBS) requires structural, electrical, mechanical, and plumbing plans. KM Builders handles all permit applications and inspections.
Can a room addition become a rental unit (JADU)?
Yes. If the addition is attached to the main dwelling and meets minimum size requirements, it may qualify as a Junior ADU (JADU) under California law - allowing you to rent it out for income. KM Builders can design your addition with JADU compliance in mind.
What types of room additions does KM Builders build?
KM Builders builds master bedroom suites, in-law suites, home offices, great rooms, sunrooms, family rooms, second-story additions, and multi-room additions. We handle all architectural drawings, structural engineering, and city approvals.
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More ways to prepare
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