A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateFast, Reliable Home Addition Contractor Across Pomona
A home addition in Pomona typically runs $180 to $420 per square foot depending on scope, finishes, and whether you’re converting existing space or building new foundation. A detached garage-to-ADU conversion on an alley-loaded Pomona lot usually lands between $140,000 and $220,000 all-in, while a bathroom addition starts around $45,000 and a full second-story addition can exceed $300,000. If you’re weighing options, call (903) 568-7222 and we’ll walk you through real numbers for your specific property, not a generic spreadsheet.
We work throughout Pomona from the 91766 and 91767 ZIP codes out to Phillips Ranch, Westmont, and the streets off North Garey Avenue. Our crews know the difference between a 1920s bungalow near Lincoln Park and a 1990s tract home south of the 10. That local familiarity means we spot slab issues, alley easements, and setback problems before they become change orders. Trust us on this: the earlier we walk your lot, the fewer surprises you’ll see in writing.
Why Benson ADU Builders Is Pomona’s Preferred Home Addition Contractor Company
Pomona homeowners keep calling us back because we put the price in writing before any work starts. No verbal estimate that drifts upward after demo day. No scope creep billed as an afterthought. Troy Eastman, who leads our team, built Benson ADU Builders on a simple rule: if the work isn’t right within 365 days, we make it right. That promise is stamped on every project we sign in Pomona.
We answer the phone live, 24/7. When you call about a garage conversion near Ganesha Park or a room addition in the Wilton Heights area, a real person picks up. The technicians who arrive at your door are background-checked and uniformed. You’ll know their name before they walk onto your property. And because we’re part of the Relay Home Co. family founded in 2006, our Pomona projects follow a documented process with real-time tracking and before-and-after photos. Did we mention the free second visit if any covered repair fails? That’s in writing too.
Garage Addition Contractors in Pomona
Garage Addition Contractors in Pomona do more than hang drywall. Most Pomona lots with detached garages sit on a rear alley, which means a conversion here usually requires the rear-facing wall to be re-framed for a new door or window, and the garage slab brought up to current code. This condition is far less common in cities without alley-loaded garages. Before we quote a garage addition or conversion in Pomona, we check slab thickness, moisture barrier presence, and alley easement lines.
Slab Reality Check
A poured-1970s Pomona slab often has no vapor barrier and is too thin to support living space. That means the existing slab fails and requires replacement, adding $8,000 to $15,000 to the job. We include this in your written quote up front, not as a surprise after demolition.
Alley Easement and Setback Review
Some Pomona lots have rear alley easements that cut into usable buildable area. Assuming a standard 4-foot setback works on paper, but if the easement encroaches, you could trigger a variance or redesign. We measure early, so your plan passes plan check the first time.
Bathroom Addition Contractor in Pomona
A Bathroom Addition Contractor in Pomona has to understand California’s separate-meter rule and vent code. Adding even a small 3/4 bath to an existing house or ADU means its own permit, its own inspection, and code-compliant ventilation. In Pomona, we routinely see bathroom additions to older homes where the existing vent stack can’t handle the new fixture count without a retrofit. That’s fine. We plan for it.
What a Pomona Bathroom Addition Costs
A ground-floor bathroom addition in Pomona typically runs $45,000 to $75,000, including foundation, framing, rough plumbing, tile, fixtures, and finish paint. A second-floor addition above an existing bedroom costs more, often $65,000 to $95,000, because we’re reinforcing floor joists and running drain stacks through ceilings.
Permits and Inspections
Every bathroom addition in Pomona requires a building permit and a plumbing permit, plus a rough-in inspection and a final inspection. We pull permits, schedule inspections, and stand behind the work. If an inspector flags something, we fix it before you ever see the report.
Trusted Brands We Service in Pomona
Benson ADU Builders is authorized to build with prefab systems from Cover, Dvele, Mighty Buildings, and Boxabl. That matters for Pomona homeowners because these aren’t kit homes that arrive on a flatbed and hope for the best. Cover’s panelized system ships precision-cut walls ready to assemble on your slab. Dvele builds factory-sealed modules with integrated sensors. Mighty Buildings uses a 3D-printed composite panel that cuts framing time dramatically. Because we’re authorized, we can order replacement panels or components fast for Pomona customers without waiting on a third-party dealer. We also stock James Hardie cladding locally, so color-matched lap siding for your addition matches the existing house.
Common Home Addition Contractor Problems We See in Pomona Homes
- Un-reinforced garage slabs failing under new load. A 1970s Pomona garage slab was poured as a parking surface, not a living floor. When we cut into it, we often find no rebar and no vapor barrier. The fix is full slab replacement, and it should be in your written price from day one, not discovered mid-project.
- Alley easements shrinking buildable area. Some Pomona lots have a rear alley easement that extends further into the lot than the fence line suggests. If your plan assumes buildable space to the property line, you may lose 4 to 8 feet of ADU width. A quick survey early saves a variance later.
- Separate-meter rule catching homeowners at plan check. California ADU law requires the unit to have its own electrical meter, water heater, and HVAC system. Some Pomona garage conversions are drawn as cosmetic remodels, and the missing separate meter only surfaces at plan check. We draw it correctly the first time, so plan check doesn’t bounce.
- Bathroom vent termination failing California code. Venting a bathroom fan into an attic or a side yard within 3 feet of a window fails inspection. On a corner lot in the Wilton Heights area, we corrected the vent termination on a garage-to-Jr. ADU conversion before final inspection so the client passed on the first attempt.
Pricing for Home Addition Contractor in Pomona, CA
Here are real Pomona ranges based on recent projects and current material costs. A garage conversion to a Jr. ADU runs $140,000 to $220,000 depending on slab replacement, electrical service upgrade, and finish level. A ground-floor bathroom addition starts around $45,000. A sunroom addition on a poured slab runs $60,000 to $110,000. A full second-story addition over an existing single-story home starts at $250,000 and climbs with structural reinforcement and stair placement. What moves the price most in Pomona: slab condition, alley easement constraints, sewer line location, and whether the main panel has capacity for a separate meter. We give you a written line-item quote so you see exactly where every dollar goes before you sign.
We Also Serve Cities Near Pomona
Benson ADU Builders serves homeowners across the eastern San Gabriel Valley and western Inland Empire. Our Home Addition Contractor team regularly works in Diamond Bar, Montclair, Chino Hills, and Claremont. If you’re in one of those cities and planning an ADU or addition, you’ll get the same written-price promise and the same 365-Day Done Right guarantee. Read more about our work across the region at our Pomona service hub.
Serving Pomona, CA - Our Local Coverage Area
We’re based in the Pomona area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs About Home Addition Contractor in Pomona
Most of the time, no. A 1970s Pomona garage slab was poured 3.5 to 4 inches thick with no rebar and no vapor barrier. Building code for living space requires a thicker slab with a moisture barrier underneath. If your slab is un-reinforced or cracked, you’re looking at $8,000 to $15,000 for demo and a new 4-inch slab with vapor barrier before framing starts. The good news: we check slab condition during the estimate, so the slab replacement is in your written price, not a surprise later. Call (903) 568-7222 to schedule a free slab inspection and estimate.
Yes, under California ADU law your attached or detached ADU needs its own electrical meter, water heater, and HVAC system. Pomona enforces this at plan check. A separate address is handled through the county assessor’s office once the unit is permitted. We draw the ADU with its own subpanel and dedicated meter from the start, so your plan doesn’t bounce back. If your main panel lacks capacity, a service upgrade may be required, and we’ll show you that cost upfront.
Plan for 5 to 8 months total. Permitting in Pomona typically takes 6 to 10 weeks depending on plan check workload and whether a variance is required. Construction on a standard 400 to 480 square foot garage conversion runs 3 to 5 months once permits are issued, assuming no slab surprises. We pull permits on your behalf and give you a written timeline before work begins, with real-time updates throughout the build.
The standard rear setback for an ADU is 4 feet from the property line, but if your garage sits on an alley-loaded Pomona lot, the alley easement may extend further onto your property than the fence line suggests. This can reduce the buildable footprint and trigger a variance or redesign. We measure the actual easement and design inside the true buildable area, so you don’t lose a rear wall to an encroachment dispute later.
Yes. Any plumbing change, including adding a sink, toilet, shower, or vent stack, requires a building permit and a plumbing permit in Pomona. You’ll need a rough-in inspection before drywall goes up and a final inspection after finish work. We pull both permits, schedule the inspections, and correct any flagged items without charging you extra for re-inspections. Call (903) 568-7222 to get a written quote for your bathroom addition.
Written by Troy Eastman, Owner at Benson ADU Builders, serving Pomona since 2006 through the Relay Home Co. family.
Ready to see real numbers for your Pomona addition? Call (903) 568-7222 for a free estimate. We answer live, we measure your lot, and we hand you a written price before any work starts.
