







A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateTrusted Room Addition Contractor for Pasadena Homeowners
Room additions in Pasadena typically run $180 to $350 per square foot before permit fees, depending on whether you’re building out, up, or converting existing space. A straightforward bump-out off a living room lands closer to the low end; a full primary suite with plumbing and a new roofline sits at the top. Fielding ADU Pasadena quotes every job the same way: a written price handed to you before a single nail goes in, so the number on day one matches the final invoice. For a detailed guide on protecting your investment, see our Room Addition Contractor Maintenance Checklist for Pasadena Homeowners. Reed Calloway leads our Pasadena operation, and every crew member who steps onto your property is background-checked and in uniform. We build the room, pull the permits, pass the inspections, and back the work with the Garrison Standard, a written one-year guarantee most contractors won’t put on paper. Call (626) 657-5541 and a live person answers, 24 hours a day.
Key Takeaways
- Pasadena room additions cost $180 to $350 per square foot, with permit fees separate.
- Fielding ADU Pasadena puts every price in writing before work starts. No change orders at the door.
- The Garrison Standard covers workmanship defects for 365 days, in writing, with a free correction visit.
- We work with Abodu, Cover, and Dvele for modular and prefab options, plus conventional frame builds.
- Every call to (626) 657-5541 is answered by a live person. Not a queue.
Sunroom Builders
Sunroom Builders in Pasadena construct glass-heavy rooms that capture light without the cost or complexity of a full conventional addition, and our sunrooms typically run $150 to $250 per square foot depending on glazing type, foundation work, and whether you want heating or cooling tied into the room. Homeowners in Highland Park and La Cañada Flintridge often choose sunrooms as reading rooms, plant rooms, or morning spaces that extend the house without the weight of a second-story addition. We frame it, flash it properly against the existing house (this is where cheap sunrooms leak), and tie the roofline in so the city inspector passes it the first time.
Glazing and Thermal Comfort
Pasadena summer sun will cook a poorly glazed room by noon. We specify low-E glass packages sized for southern exposure and add operable vents or a ductless mini-split so the room stays usable in August, not just March.
Foundation Matching for Older Pasadena Homes
Many Bungalow Heaven and Madison Heights homes sit on raised foundations that have settled unevenly over 80 years. Before we set a sunroom, we check the tie-in point for level and shim or pour as needed so the new slab doesn’t pull away from the old house.
Room Additions

Room Addition Contractor - Pasadena projects cover anything from a 150-square-foot bedroom bump-out to a full family room extension, and our work lands between $180 and $300 per square foot with permit fees quoted separately because the City of Pasadena calculates those on valuation. The trigger is usually the same: the house works, the lot works, but the kitchen table is ten feet from the front door and the kids are sharing a bedroom. We frame in dimensional lumber or steel where the span calls for it, match the existing roofline and stucco or siding, and keep one written price from first walkthrough to final inspection. Reed Calloway has built enough additions in Pasadena to know which setbacks on which streets will require a variance, and we flag that before you spend a dollar on plans.
Second-Story Additions in Pasadena
Going up is often the right answer on small lots in East San Gabriel and South El Monte where a side yard doesn’t exist. A second-story addition costs more per square foot, usually $250 to $350, because we’re opening the roof, adding stairs, and reinforcing the first-floor walls and footing. We pull the structural engineering, file with the City of Pasadena, and build the framing in a sequence that keeps the lower floor weathertight at the end of every workday.
Bump-Outs and Widenings
A 4-foot bump-out along a back wall can add 80 to 120 square feet and solves more problems than people expect: a real dining nook, a laundry room, a home office. These run closer to the $180 per square foot floor and usually clear the city’s plan check in two to three weeks. We still pull the permit, set the foundation to code, and match the trim so the addition doesn’t read as an afterthought.
Modular Home Addition
Modular Home Addition in Pasadena means the room is framed in a factory, delivered in sections, and set on a prepared foundation, and for homeowners in Temple City and Montebello dealing with tight yards or a short construction window, a Room Addition Contractor in Temple City can use this method to cut on-site framing time by half or more. A modular addition typically runs $200 to $325 per square foot all-in before permits, with the factory portion priced by the module and the site work (foundation, crane set, utility tie-in, finish trim) priced separately by Fielding ADU Pasadena. We work with Abodu, Cover, and Dvele on modular projects, and we’ve found the right fit depends on lot access more than anything else. A 40-foot module doesn’t do you much good on a street where the crane can’t get within 30 feet of the set point.
Crane Access and Lot Logistics
Before you order a module, we walk the site in Pasadena with a tape measure and a view toward the street. Overhead wires, narrow driveways, and tree canopies decide whether a crane set is even possible. If it isn’t, we tell you on the first visit, not on delivery day.
Factory Precision vs. Pasadena’s Field Conditions
Modules arrive square and tight, which is the point. The work on our end is the marriage to the existing house: flashing the joint, tying in electrical and plumbing, and making the transition from factory floor to Pasadena foundation look intentional. That tie-in is where a modular addition succeeds or leaks, and it’s the part we price in writing up front.
Home Addition Plans

Home Addition Plans in Pasadena are the measured drawings, structural calcs, and city submittal set required before the City of Pasadena issues a building permit, and good plans for a room addition typically cost $1,800 to $6,000 depending on the scope and whether structural engineering or a title-24 energy report is required. We deliver a written price for the plans and the build separately, so you know exactly what the design phase costs before you commit to construction. No homeowner should pour money into framing only to find the planning department wants a soils report; we walk the whole permit path with you from the first sketch. We also check your property’s zoning designation, because Pasadena’s rules change by neighborhood and by hillside ordinance in places like La Cañada Flintridge.
Zoning and Setback Review Before You Pay for Drawings
We check the parcel’s setbacks, lot coverage limits, and any historic district overlays before a draftsman marks up a single wall. A surprising number of Pasadena properties have nonconforming setbacks that grandfather in only if you don’t expand, and the wrong plan hits a wall at plan check. Better to know on day one.
Structural Reality Checks on Older Framing
Plans are paper until they meet the house. We open the relevant wall or attic first and confirm the existing headers, footing, and shear capacity match what the drawings assume. If the plan says a 4×12 header will carry the new load, we verify that before you pay for the permit set.
In Law Suite Builders
In Law Suite Builders in Pasadena construct attached or detached accessory units designed for an aging parent, an adult child, or a long-term guest, and these suites run $250 to $400 per square foot because they carry a bathroom, a kitchenette, and separate egress. The City of Pasadena treats in-law suites under its ADU ordinance, which means a detached unit needs its own setbacks and a deed restriction in some cases, but the permitting path is now faster than it was five years ago. We build them with a separate entrance and a door that can lock from both sides, and we frame the walls with sound attenuation in mind so a family member can live close without living on top of each other. Reed Calloway has built in-law suites across Pico Rivera and Highland Park, and every one of them starts with a written price. We also serve as a Room Addition Contractor - San Marino for homeowners expanding their living space.
Detached In-Law Suites with Kitchenettes
A detached in-law suite in a Pasadena backyard gives both houses real privacy and adds usable square footage that can convert to rental income later. We run the water and sewer lines in the same trench, set the pad with proper drainage away from the main house, and finish the interior so it doesn’t feel like a garage with drywall.
Attached Suites with Separate Entrances
When the lot is too narrow for a detached unit, we convert an existing bedroom wing or add onto the rear corner with its own exterior door. The key is the fire separation and the sound assembly between the suite and the main house. We build to a one-hour rating and use insulation and resilient channel so a television in the suite doesn’t shake the bedroom wall on the other side.
ADU Conversion

ADU Conversion in Pasadena turns an existing garage, basement, or underused room into a legal accessory dwelling unit, and a garage conversion typically runs $180 to $280 per square foot with permit fees separate, which is why so many Pasadena homeowners choose it over a ground-up ADU. The structure is already there: walls, roof, foundation. What you’re paying for is the transformation: insulation, drywall, a new floor, plumbing for a bath and kitchen, and a separate electrical panel because the garage’s existing circuit won’t carry a refrigerator and a microwave. We convert attached garages in neighborhoods like Mayflower Village and South San Gabriel, and detached garages across Arcadia, and the result is a rentable unit or a guest house that pays for itself over time.
Garage Conversions the City Will Sign Off On
Pasadena requires converted garages to meet the same energy and habitability standards as new construction, which means the old slab gets a moisture barrier, the walls get insulation, and the roof gets ventilation. We also file for the change of use so the unit is legal, not a workaround. A converted garage without paperwork is a liability when you sell.
Replacing the Parking You Lose
The City of Pasadena lets you convert a garage in many zones, but you may need to provide a replacement parking space or show the ADU is within a half-mile of transit. We check that requirement before you commit, and if a new driveway approach or tandem space is needed, that cost is in the written estimate, not discovered at framing.
Brands We Service
We build and finish James Hardie siding on conventional additions, because in Pasadena’s dry summers and wet winters, fiber cement holds paint and resists termites better than wood. The 1-inch reveal and the color match to the existing house is part of why our additions look like they’ve always been there.
On the modular side, we work with Abodu and Cover for factory-built units delivered to Pasadena lots. Abodu’s California-specific designs clear the state’s ADU pre-approval process quickly, and Cover’s steel-frame panels arrive flat-packed for tight lots where a crane is out of the question. We handle site work, foundation, utility hookups, and the final trim so the factory shell finishes like a custom build. If you’re weighing Abodu against Cover or Dvele against a stick-built room, we’ll walk you through the real numbers before you sign with a factory rep.
Signs You Need a Pro Right Now
- Visible cracks running diagonal from window or door corners. These often signal foundation movement or header failure in the existing wall. If you’re planning an addition that ties into that wall, the problem has to be addressed before we frame against it.
- A roofline that sags between the ridge and the eaves. That’s a sign the rafters or the supporting wall are overloaded, and adding a room next to that section compounds the load. We inspect the structure and put the fix in the written scope before anything else moves forward.
- Doors and windows that stick seasonally in a Pasadena summer. Expansion and contraction happen, but if a door jams every August, the foundation or the framing is moving more than it should. A room addition built on unsteady ground inherits the problem.
- Standing water or damp staining on the wall where your addition would attach. You don’t want to build against a wall that’s already failing at the flashing or the stucco. We trace the water before we frame, or you’ll be fixing it twice.
- An unpermitted garage conversion or sunroom already on the property. If previous work was done without permits, the City of Pasadena can flag it when we file for new permits. We can often bring it into compliance as part of the new project, but the earlier we know, the cheaper the fix.
Our Process, Step by Step
- 1
Initial Walkthrough and Site Measure. Reed or one of our lead builders walks the property with you, takes the existing floor plan, checks the lot lines, and listens to what the room actually needs to do. We don’t bring a brochure; we bring a tape measure and a notebook.
- 2
Written Scope and Price. Within days, you get a line-item written estimate covering demo, foundation, framing, roofing, drywall, finish, materials, and our labor. The price you approve is the price on the final invoice. No allowances that creep.
- 3
Plans, Permits, and Engineering. We prepare or coordinate the drawings, pull structural calcs, and file with the City of Pasadena. We handle the plan check comments and resubmissions so you don’t spend afternoons at the permit counter.
- 4
Construction and Weekly Updates. The crew arrives in uniform, background-checked, and works through the agreed sequence. You get a weekly progress note with photos, so you always know what happened and what’s next. We keep the site clean at the end of every day.
- 5
Final Inspection and the Garrison Standard. The city inspector signs off, we walk the room with you room by room, and you get the written one-year guarantee. If something fails inside 365 days, we come back and make it right at no charge.
How Much Does Room Addition Contractor Cost in Pasadena?
A typical room addition in Pasadena runs $180 to $350 per square foot. A simple bump-out on a level slab at the rear of the house can land around $180 to $220 per square foot. A full guest room with a bathroom, new roof tie-in, and upgraded finishes runs $280 to $350. Sunrooms run lower, $150 to $250 per square foot, because they don’t carry the same structural or insulation load. An attached in-law suite with a kitchenette usually starts around $250 per square foot and climbs with finishes. A garage-to-ADU conversion runs $180 to $280 per square foot because the shell is already there. Permit fees in Pasadena are calculated on project valuation and run separately; we quote them on the written estimate.
What moves the price: the condition of the existing foundation, the roofline tie-in (a simple shed tie is cheaper than a full ridge integration), the plumbing rough-in distance from the main waste line, and the finish level. Hardwood, custom millwork, and tile add real cost. You avoid overpaying by getting a written, line-item price before any work starts, and by choosing a contractor who doesn’t run allowances. Every free estimate from Fielding ADU Pasadena includes the full written scope and price. Call (626) 657-5541 to schedule yours.
Our Service Area Near Pasadena
Fielding ADU Pasadena builds room additions across home base in Pasadena and the surrounding communities: Burbank, Arcadia, Pico Rivera, Temple City, Highland Park, Montebello, La Cañada Flintridge, South El Monte, East San Gabriel, South San Gabriel, and Mayflower Village. If you’re in Burbank or Pasadena proper, we can usually have someone on-site within a few business days of your call. Crews are dispatched from our Pasadena yard, so a site measure in Arcadia or Temple City doesn’t carry a travel surcharge.
Serving Pasadena, CA - Our Local Coverage Area
We’re based in the Pasadena area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
Frequently Asked Questions About Room Addition Contractor in Pasadena
A room addition contractor is a licensed builder who designs, permits, and constructs new square footage attached to an existing house. In Pasadena, this includes site measure, structural evaluation, plans, city submittal, foundation work, framing, roofing, drywall, and finish. Fielding ADU Pasadena handles every step with a written price before work starts, and every project is backed by the Garrison Standard one-year written guarantee. Call (626) 657-5541 and a live person answers any time.
A simple bump-out typically takes 6 to 10 weeks from first inspection to final sign-off. A larger addition with a bathroom or a second-story component runs 12 to 20 weeks, including the City of Pasadena plan check, which is currently running several weeks depending on the department’s workload. We give you a written schedule with the written price, and we update you weekly with photos and a short note. Call (626) 657-5541 for a timeline specific to your project.
Room additions in Pasadena run $180 to $350 per square foot before permit fees. A 300-square-foot bedroom bump-out on a slab typically costs $54,000 to $70,000; a 500-square-foot primary suite with a bathroom runs $140,000 to $175,000. Permit fees are separate and quoted on the written estimate. Call (626) 657-5541 for an exact quote, estimates are free.
Yes. We install James Hardie fiber cement siding on conventional additions throughout Pasadena, Burbank, Arcadia, and the surrounding areas. We match the existing reveal and paint scheme so the addition blends with the original house. James Hardie’s fiber cement is resistant to termites and holds paint in Pasadena’s dry heat better than wood. Call (626) 657-5541 to discuss siding options.
Our phone line is answered by a live person 24 hours a day, 7 days a week, so if you have a structural issue that threatens the house, we’ll get someone on the line immediately and have a crew out as soon as conditions allow. Construction projects themselves are scheduled, not dispatched as emergencies, but we respond fast when a failing wall or a damaged tie-in puts your house at risk. Call (626) 657-5541, a person picks up.
Every room addition is backed in writing by the Garrison Standard: a one-year, 365-day guarantee covering workmanship defects. If something fails inside that year, we return at no charge and correct it. It’s written down, not implied, and it covers what it covers in plain language. Call (626) 657-5541 for the details before you sign anything.
Pull any old surveys, plot plans, or previous permit records you have, and make a short list of what the room needs to do, how much natural light you want, and where the furniture goes. That saves us a full round of back-and-forth. We handle the rest: the measuring, the zoning check, the plans, and the permit. Call (626) 657-5541 to schedule your free walkthrough; our Room Addition Contractor in Pasadena page has more detail.
Schedule Your Room Addition Contractor Service in Pasadena Today
You’ve seen enough contractor math to know what a moving price looks like. Ours doesn’t move. Written price before work starts, one year of written guarantee after it ends, and a live human on the phone whenever you call. Call (626) 657-5541 and schedule a free walkthrough with Fielding ADU Pasadena today.
Written by Reed Calloway, Owner at Fielding ADU Pasadena, serving Pasadena since 2006.









