A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateTrusted Home Addition Contractor for Pasadena Homeowners
Adding square footage to a home in Pasadena means working within a specific set of rules: lot coverage limits, setback requirements, and the city’s design review process for certain historic neighborhoods. A home addition contractor in Pasadena who knows those rules before the first stake goes in the ground saves a family months of frustration. Since 2001, the Cedarwell family of companies has built additions across the San Gabriel Valley, and Seedling ADU Pasadena carries that experience into every room we add. We’re led by Ben Ortega, and we answer the phone when you call: (626) 657-5461.
Our approach to home additions in Pasadena is simple: a written price before work begins, a 365-Day Done Right Promise on every project, and crews who treat your home like it matters. We work near bedrooms during school hours with quiet tools when possible, lay drop cloths from the entry to the work zone, and send you a photo of the clean-up before we leave each day. That’s the Cedarwell Care Promise, and it applies to every home addition we build.
Sunroom Addition
A Sunroom Addition gives Pasadena families a bright, glass-filled room that works as a playroom, reading nook, or morning coffee space without the full cost of a conventional addition. Because sunrooms in Pasadena don’t always require the same foundation depth as a standard room, they can often be permitted and built faster, though on hillside lots in areas like Linda Vista or San Rafael, the engineering step matters more and the price reflects it. Seedling ADU Pasadena handles the design, the permits, and the build, and our written quote includes every line item before any tool is picked up.
A sunroom addition in Pasadena typically runs between $45,000 and $90,000 depending on glazing choices, whether the room needs heating and cooling, and the condition of the exterior wall it ties into. We’ll walk you through what each material choice does to the final number, and the price on paper doesn’t change once crews arrive.
Glass Selection and Passive Heat
South-facing sunrooms in Pasadena pick up a lot of afternoon heat, so we spec low-E glass and operable windows to keep the room comfortable without running the AC all day. This matters more in neighborhoods like Madison Heights or Bungalow Heaven, where many homes lack whole-house cooling in the rear of the house.
Foundation Types for Sunrooms
Most sunroom additions in Pasadena work well on a slab-on-grade foundation, but if your yard slopes, we’ll bring in a soils engineer and quote a pier-and-beam or raised foundation. The foundation choice is where cheap bids hide surprises; ours are itemized and explained.
Room Addition Contractor
A Room Addition Contractor handles the ground-up build of a new living space attached to your home, whether that’s a family room, an office, or a multi-use flex space. In Pasadena, the most common room additions we build are attached to the rear or side of single-story homes in neighborhoods like Hastings Ranch and Northeast Pasadena, where the lot allows a modest bump-out without triggering a variance. Seedling ADU Pasadena manages everything from architectural drawings to the final coat of paint.
Room additions in Pasadena generally cost between $120,000 and $220,000 depending on square footage, roofline complexity, and whether the addition shares a wall with the kitchen or a bathroom, which brings plumbing into scope. We also coordinate with the city on setbacks and lot coverage so the permit process moves without surprises.
Attached vs. Bump-Out Designs
An attached addition with its own roofline and foundation behaves differently from a bump-out that extends an existing roofline. We’ll assess your lot and your existing framing, then price the simpler route when it makes sense, rather than selling the bigger build.
When the Existing Roof Must Tie In
Pasadena’s rainy winters mean the roof tie-in is the detail that matters most. If a room addition isn’t flashed and graded correctly where old roof meets new, the first good storm finds its way inside. Our crews inspect the existing roof deck before quoting, and the fix is in the written price.
Second Story Addition Contractor
A Second Story Addition Contractor builds upward when a Pasadena lot doesn’t have room to expand outward. This is common in denser neighborhoods like Old Pasadena, South Lake, and the condo-heavy pockets near Caltech, where the lot is small but the zoning permits a second floor. Seedling ADU Pasadena evaluates the existing foundation and first-floor framing before we quote, because a second story adds weight that the original structure wasn’t designed to carry.
Second story additions in Pasadena typically cost between $250,000 and $400,000, with the wide range driven by whether the first floor needs seismic retrofitting, whether the family stays in the home during the build, and how much of the existing roof must be removed and rebuilt. This is not a project to price over the phone, which is exactly why our estimator walks the home before any number goes on paper.
Foundation and Seismic Requirements
Pasadena sits in a high-seismic zone, and city code requires an engineered foundation check for any vertical addition. We bring in a licensed structural engineer on every second story project and include the engineer’s scope in the written quote, not as a change order later.
Living In Place During the Build
Many families stay in the home while we build above them. We schedule noisy demolition for specific windows, seal the lower floor from dust with plastic barriers and boot covers, and keep the stairwell route clear and swept each evening.
Garage Addition Contractors
Garage Addition Contractors build new attached or detached garage structures, or expand an existing garage into a larger workshop, storage, or parking space. In Pasadena, where many homes were built in the 1920s and 1930s with single-car garages or carports, most garage addition work involves either replacing a crumbling detached garage or adding a second bay. Seedling ADU Pasadena also knows the garage conversion option well, and we’ll tell you honestly if a Home Addition Contractor in Glendale-style conversion makes more financial sense than a new garage structure.
Garage additions in Pasadena usually run from $40,000 for a simple single-bay rebuild to $90,000 for a larger two-car structure with storage above. The price depends on whether we’re tying into the house, running new electrical for EV chargers or tools, and what condition the existing slab is in.
ADU Conversion Potential Above the Garage
Many Pasadena homeowners build a new garage with an ADU above it, and our team builds both scopes together. Combining the two projects saves money on permitting, foundation, and mobilization, and it turns dead garage space into an income-producing rental.
Detached vs. Attached Garage Additions
An attached garage addition requires fire-rated separation between garage and living space, while a detached garage has simpler code requirements but costs more for utility trenching. We quote both approaches when the lot allows, so you can compare real numbers.
Bathroom Addition Contractor
A Bathroom Addition Contractor builds a new full or half bath where one doesn’t exist, which usually means a new wet wall, drain line, vent stack, and waterproofing. In Pasadena ranch homes and Craftsman bungalows, the most common request we hear is a first-floor bathroom for aging parents or a primary suite bath where the master currently shares the hall bath. Seedling ADU Pasadena handles the full build, and we schedule the water shut-off window in advance so your morning routine isn’t unexpectedly interrupted.
Bathroom additions in Pasadena typically cost between $40,000 and $85,000. The big variables are drain line access (slab foundation homes cost more to trench), whether you’re adding to an exterior wall or an interior closet, and tile and fixture choices. Our written quote separates rough-in plumbing, waterproofing, tile, and fixtures so you see exactly where the money goes.
Waterproofing and Drain Access
A bathroom addition fails from moisture if the pan, substrate, and venting aren’t done right. We use cement board and a full waterproof membrane system, and we show you the waterproofing before the tile goes on.
Adding Baths Without Moving Walls
Sometimes a Pasadena home has an oversized closet or laundry room that can become a bath without structural changes. We look for the cheapest path that meets code, because we’d rather earn your trust on this project than upsell you into a larger one.
Bedroom Addition Contractor
A Bedroom Addition Contractor builds a new sleeping room that meets California Building Code for egress, light, ventilation, and closet space. In Pasadena, bedroom additions are often driven by a growing family, a new baby, or a parent moving in, and the most common location is a rear addition off the hallway or a conversion of an enclosed porch. Seedling ADU Pasadena handles the floor plan, the egress window, the heating and cooling, and the closet, so the new room is a real bedroom, not just a labeled space.
Bedroom additions in Pasadena typically cost between $90,000 and $180,000. The range is wide because some additions tie into existing HVAC ducting while others need a mini-split, and some require structural changes to the exterior wall. Our quote includes the egress window sizing, closet build, and door hardware, and we explain what the city inspector will look for before they arrive.
Egress Windows and Smoke Requirements
Every legal bedroom in Pasadena needs an egress window with minimum dimensions and a smoke alarm wired into the home’s system. We handle these details in the scope of work, and we don’t call a room a bedroom unless it passes.
Adding a Bedroom vs. Converting a Garage
Sometimes a garage conversion gives a family the extra bedroom they need for less money than a ground-up addition. Seedling builds both, so we’ll show you the numbers for each path and let you decide. If you’re considering that route, our Home Addition Contractor in Alhambra page covers similar options for homes just east of Pasadena.
Brands We Service
Seedling ADU Pasadena works with the building systems serious buyers research before calling anyone. We install and finish James Hardie fiber cement siding on additions and ADUs throughout Pasadena, and we’ve learned which Hardie profiles hold up best in the San Gabriel Valley’s dry heat and occasional heavy rain. For detached additions and ADUs, we’re a hands-on partner for Abodu and Dvele prefab units, which means we handle the site work, foundation, utility connections, and finish details so the factory-built module integrates cleanly with your existing home.
Whether you have a James Hardie-clad addition in mind or want to explore a prefab system from Abodu, Cover, or Dvele, we can help you compare real product costs and lead times. The right product for your lot isn’t always the one the builder prefers to sell, and we’d rather you choose from facts than from a single catalog.
Signs You Need a Pro Right Now
- Your family has outgrown the common areas. When kids are doing homework at the kitchen table and adults are working from the bedroom, the home is telling you something. A room addition restores function without requiring a move across town.
- You need a parent or in-law close by. An ADU or attached addition with a separate entrance lets an aging parent live independently while staying near family. Waiting until a health crisis forces the move usually means paying more for rush work.
- Your home’s value is capped by its square footage. Pasadena buyers in neighborhoods like San Marino-adjacent East Pasadena and Linda Vista compare square footage first. A bedroom or bath addition often recovers a large share of its cost at sale.
- You’re working from home without a real office. Video calls from the dining room are temporary until they aren’t. A small office addition or ADU with a separate entrance keeps work from interfering with family life.
- You keep pushing off structural concerns. Cracks in the foundation or a sagging porch roof only get more expensive. A contractor who inspects and prices the fix now saves you from a bigger bill later.
Our Process, Step by Step
Every Seedling home addition in Pasadena follows our Home Addition Contractor Maintenance Checklist for Pasadena Homeowners across the same five steps, so there are no surprises in the schedule or the price.
- 1
Walk the property and measure. Ben Ortega or a senior Seedling estimator visits your home in Pasadena, measures the lot, checks access for equipment, and photographs the existing conditions. We’ll ask about your goals and listen more than we talk.
- 2
Scope and written price. We send a line-item quote that includes permits, materials, labor, and the specific brand choices you’ve asked about. No allowance games, no “to be determined” lines. The price is the price.
- 3
Permit drawings and city submittal. We work with the City of Pasadena’s building division to get drawings approved, and we flag any zoning or lot-coverage questions before submittal. If the city asks for changes, we handle the resubmission and tell you what it means.
- 4
Build with daily clean-up. Our background-checked, uniformed crew shows up when we said they would. Shoe covers and drop cloths go down before work starts, and you get a photo of the clean-up each evening before we leave.
- 5
Walkthrough and the 365-Day Done Right Promise. We walk the finished addition with you, fix anything that’s not right, and hand you the written 365-Day Done Right Promise. If it’s not done right, we make it right, in writing.
How Much Does Home Addition Contractor Cost in Pasadena?
A home addition in Pasadena costs between $40,000 and $400,000 depending on the type of project. A simple garage rebuild or sunroom starts around $40,000 to $90,000. A single room addition lands between $120,000 and $220,000. A second story addition runs $250,000 to $400,000, with the high end reserved for homes that need structural upgrades while the family stays in place. Bathroom and bedroom additions fall in the middle, generally $40,000 to $180,000 depending on plumbing access and finish level.
What moves the number: foundation type (slab vs. raised), seismic retrofit requirements on second stories, whether the addition ties into existing HVAC or needs its own system, and the finish materials you choose. To avoid overpaying, get a quote that line-items the permit cost, the structural work, the rough-in, and the finishes separately. Bundled quotes hide markup. Our free estimate includes a written breakdown you can compare against any other builder, and the price on paper is the price you pay. No change orders, no surprise line items.
Our Service Area Near Pasadena
Seedling ADU Pasadena builds home additions throughout Pasadena, East Pasadena, and the surrounding San Gabriel Valley communities. We’re regularly on job sites in Glendale, Alhambra, Baldwin Park, Rosemead, Monrovia, Atwater Village, Maywood, Tujunga, Avocado Heights, and Sierra Madre. If you’re outside Pasadena proper, our Home Addition Contractor in Pasadena team covers the whole area, and we schedule estimates Monday through Saturday. Call (626) 657-5461 and we’ll find a time that works around your family’s routine.
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 Home Addition Contractor in Pasadena
A home addition contractor in San Marino or Pasadena plans, permits, and builds new attached living space on your existing home. Seedling ADU Pasadena handles the architectural scope, city permit submittal, foundation, framing, roofing, electrical, plumbing, HVAC, drywall, paint, and finish work. We also manage the inspections with the City of Pasadena so the addition is legal and insurable when we’re done. Call (626) 657-5461 to talk through your project.
Most single-room additions in Pasadena take 3 to 5 months from permit submittal to final walkthrough. Second story additions run 6 to 9 months because the structural and roofing phases are longer. Your written schedule comes with the written price, and we’ll tell you if the city’s permit queue will add time before you sign anything.
Home additions in Pasadena range from $40,000 for a simple garage or sunroom to $400,000 for a full second story. The most common project, a single room addition, usually lands between $120,000 and $220,000. Your free estimate from Seedling includes a line-item breakdown so you can see exactly what’s driving the number. Call (626) 657-5461 to schedule it.
Yes. Seedling ADU Pasadena installs James Hardie siding on additions throughout Pasadena and partners with Abodu, Cover, and Dvele for prefab ADU and addition systems. We’ll show you real product costs and lead times for each brand so you can decide based on facts, not a sales pitch.
We schedule new projects in Pasadena based on our current build calendar and the city’s permit timeline, and we’ll give you an honest start date before you commit. If a structural issue makes your home unsafe, we’ll prioritize it and get a crew to assess the situation quickly. Call (626) 657-5461 and we’ll talk through your timeline.
Every home addition Seedling builds is covered by our 365-Day Done Right Promise, which we hand you in writing at the final walkthrough. If anything isn’t done right within the first year, we make it right. Our crews also stand behind their finish work, and we answer the phone when you call about a concern.
Clear the area where the addition will go, move anything fragile away from the shared wall, and plan where the crew will park and walk. We’ll bring the shoe covers, drop cloths, and plastic barriers, and we’ll send you a photo of the clean-up every evening. If you have pets, let us know and we’ll use pet-safe products and keep gates closed as we come and go. Call (626) 657-5461 and we’ll walk you through the prep checklist for your specific project.
Schedule Your Home Addition Contractor Service in Pasadena Today
You don’t need to decide today. You need a real price and a straight answer. Call Seedling ADU Pasadena at (626) 657-5461 and we’ll schedule a free, no-obligation walkthrough of your Pasadena home. You’ll get a written, line-item quote, and we’ll answer every question you have about the process, the permits, and the schedule. No pressure, no surprises.
Written by the team at Seedling ADU Pasadena, serving Pasadena and the San Gabriel Valley with home additions, ADUs, and garage conversions.
