Home Additions & ADU in Pasadena - One Fixed Price, Permits Handled

Fast, Reliable Home Additions & ADU Across Pasadena

Adding square footage to a Pasadena home rarely starts as a simple framing job. It starts with a question about the Raymond Fault, or what the Bungalow Heaven board will allow on the exterior wall, or whether the city will flag a cripple-wall on a 1922 Craftsman you thought was fine. Home additions and ADU construction in Pasadena typically run $45,000 to $130,000 for a room addition and $90,000 to $220,000 for a new detached ADU. The numbers climb because the paperwork does, but the estimate is free, and it comes with a real person who answers the phone: (877) 610-1318.

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We’re Barrett & Sons Construction, and Tom Barrett has been running crews in the San Gabriel Valley since 1998. Around Pasadena that means our team knows the difference between a plan check in 91103 and a fire-zone review in 91107 before the first truck rolls. Nothing about working in this city surprises us anymore, and that’s the point.

Why Barrett & Sons Construction Is Pasadena’s Preferred Home Additions & ADU Company

For over 29 years, homeowners in South Pasadena, San Marino, Altadena, and every corner of greater Pasadena have hired us because of what doesn’t happen. The price doesn’t change at the end. The crew doesn’t rotate through strangers. The permit doesn’t become “optional” once the wall is open. Tom Barrett’s name, address, and license number are published and verifiable. Ask anyone on your street, or look up the license number yourself.

Tom’s sons run the crews. Background-checked crew members carry the Barrett & Sons name and show up in uniform on every visit. The 90-Day Done Right Promise is written on every contract, not buried in fine print: if it’s not done right, Tom comes back and makes it right, one call. Pasadena clients working on historic homes value written change orders more than most because they’ve often been surprised before by a scope shift mid-permit. Every allowance, every change order, arrives in writing before work happens. The allowance that isn’t on paper is a surprise waiting for a date.

We coordinate scheduling and dispatch from our Los Angeles office, but crews serve Pasadena locally. A live person answers the phone 24 hours a day, 7 days a week, not a voicemail box or an out-of-state center.

Our Home Additions & ADU Services in Pasadena

This city has very specific add-on language in its municipal code around accessory dwelling units. We work within it every week. Here’s what our Home Additions & ADU team handles most often in Pasadena.

ADU Design & Permitting

Detached ADUs in Pasadena trigger design review if the lot sits inside a historic district, which many do. We’ve taken projects through the Pasadena Historic Preservation Commission that required Secretary of the Interior Standards-compliant window trim and roof pitch adjustments before the city would sign. We handle the drawings, the structural calcs, the HPC submittal, and the building permit. The inspector works for you, not for me, and that’s exactly why we want the paperwork right the first time.

Garage Conversion ADU

Older Pasadena garages frequently sit on shallow concrete slabs with no anchor bolts and no frost-depth footings. A garage conversion ADU habitually triggers a full foundation evaluation and seismic retrofit before the interior walls go up, especially in the older apartment corridors along Lake Avenue and Fair Oaks. We budget for that from the start. Nobody wants to discover a mandatory cripple-wall bolt-down halfway through a $65,000 conversion.

New Detached ADU

A new detached ADU in Pasadena’s foothill ZIP codes, 91107 and northern 91103, must meet Wildland-Urban Interface requirements: Class A roofing, ember-resistant vents, ignition-resistant siding. Jobs on the flat valley floor don’t carry those material costs, which is why two identical ADU plans one mile apart can land $18,000 apart in bid. We scope it in writing before you sign, so you see the fire-safety line items and why they’re there.

Junior ADU & Interior Conversion

Junior ADUs inside an existing home remain the fastest path to a legal rental unit in Pasadena because they usually avoid the full site review a detached unit triggers. We build out interior conversions with separate entries where the original floor plan allows, keeping the permit file simple and the timeline shorter. These projects lean on our Kitchen Remodeling in Pasadena chops when the plan includes a kitchenette.

Trusted Brands We Service in Pasadena

When an addition or ADU calls for new windows or doors, we install names Pasadena homeowners can research before they sign: Simonton, Ply Gem, and PGT. No mystery brands off the back of a van. Ply Gem’s higher-end lines hold up well in foothill sun exposure, and PGT’s impact-rated options matter to clients near the wind corridors that funnel through the San Gabriel passes. We keep common stock accessible for Pasadena projects and order any special sizes direct. If the window schedule changes, you see the line item in writing before the order goes in.

Common Home Additions & ADU Problems We See in Pasadena Homes

• Historic district design review stops the project cold. Bungalow Heaven, Prospect Park, and Madison Heights all have active design boards with real authority over exterior alterations. Homeowners who pull a permit without anticipating HPC review can lose months.
• Pre-WWII foundations fail modern anchor requirements. Homes built between 1905 and 1940 were commonly bolted with nothing but gravity. The city’s seismic scrutiny around the Raymond Fault forces retrofits on additions that adjacent cities would pass with a simpler scope.
• Foothill fire-zone mandates add unplanned material costs. In 91107 and the northern edge of 91103, ember-resistant vents and Class A materials are not upgrades. They’re code. Contractors unfamiliar with the zones underbid and then surprise the owner mid-job.
• Old-growth framing resists modern connectors. Remodelers drilling into 1920s redwood and fir routinely snap standard bits and strip ordinary hardware. Crews without experience on this housing stock slow down or damage original framing, and that cost lands somewhere at the end.

Pricing for Home Additions & ADU in Pasadena, CA

We Also Serve Cities Near Pasadena

Our crews handle additions and ADU builds across the western San Gabriel Valley. You’ll find us in South Pasadena, where the small-lot zoning rules get tight, and in San Marino, where estate-scale additions are the norm. We also cover Bathroom Remodeling in Pasadena work throughout Altadena and East Pasadena. Same crew, same written change orders, same 90-Day Done Right Promise.

FAQs - Home Additions & ADU in Pasadena