







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 La Verne
If you’re adding a bedroom, bathroom, or full second story to a home in La Verne, you’ll want the real numbers before anyone swings a hammer. A site-built room addition in La Verne typically runs $250 – $400 per square foot. A bathroom addition sits between $45,000 and $85,000. A primary-suite or bedroom addition often lands between $90,000 and $150,000. Those are honest ranges from our work across the city, and they account for the slope, soil, and setback realities we’ll get into below.
Benson ADU Builders handles the whole job: design, permits, foundation, framing, mechanical, finishes, and final inspection. Troy Eastman leads our team, and every project gets our 365-Day Done Right Promise in writing. That means a written price before we start, a written guarantee on the work, and a free second visit if a covered repair fails within a full year. Call (903) 568-7222 to get your free estimate started.
Why Benson ADU Builders Is La Verne’s Preferred Home Addition Contractor Company

La Verne homeowners regularly tell us the same thing: they called us because our price was in writing before work started, not after. That’s the Relay Visibility Guarantee, and it’s stamped on every project we do. You get a fixed price, real-time job tracking, and photo documentation of the work as it progresses. No verbal estimate that shifts once the drywall comes off.
We know the difference between a flat grid lot near Damien Avenue and a sloped alluvial-fan lot up toward the foothills. That matters. A contractor who prices a north-side addition by square footage alone will understate foundation and drainage costs, and you’ll feel it when the change order arrives. We scope for slope, soil, and setback from the first walk-through. Our background-checked, uniformed crew shows up when we say they will, and a live person answers the phone around the clock.
We’re part of the Relay Home Co. family, established in 2006. Each location is independently owned and operated. We build with prefab and materials brands homeowners can research themselves: James Hardie, Abodu, Cover, Dvele. You get curated options, not a single take-it-or-leave-it product.
Bathroom Addition Contractor in La Verne
A Bathroom Addition Contractor in La Verne has to plan for more than tile and fixtures. On older homes near the 210 corridor, we’re often tying into cast-iron drain lines that need replacement, or stepping a footing to handle the natural grade behind Baseline Road. Our crew builds full baths, half baths, and primary-bath additions, handling everything from the wet-wall rough-in to the final vanity install.
Full Bath vs. Half Bath Scope
A full bath addition on a La Verne home usually means new supply and waste lines, ventilation to code, waterproofing, and a dedicated circuit for a receptacle and lighting. A half bath is simpler and cheaper, but the layout still has to respect egress, window sizing, and the existing floor framing. Most full bath additions here run $45,000 – $75,000, and a primary bath with higher-end finishes can reach $85,000.
Working Around La Verne Lot Grades
Where the lot slopes, we may need to step the foundation or add a retaining detail before any plumbing goes in. That’s the kind of cost a plan-and-permit set should capture before demo, not after. We pull permits and pass inspections, and we tell you the drain and vent plan before we cut into the slab.
Bedroom Addition Contractor in La Verne

A Bedroom Addition Contractor in La Verne has to account for lot-coverage limits, egress window requirements, and the age of the roof framing on the existing house. Whether you’re adding a ground-floor bedroom near Bonita High School or expanding a second story closer to Brackett Field, the job starts the same way: we measure the existing footprint, confirm setbacks, and price the foundation honestly.
Ground-Floor Bedroom Additions
These typically run $90,000 – $140,000 in La Verne, including foundation, framing, drywall, insulation, flooring, and final paint. Egress is the detail that catches people off guard: every bedroom needs a code-compliant escape window, and that changes wall framing and header sizing. We spec it correctly the first time, so the inspector signs off without a correction notice.
Primary-Suite Additions with Bath
Adding a primary suite with a dedicated bath pushes the range to $120,000 – $150,000. You’re combining two wet walls, a larger footprint, and often a walk-in closet. On sloped lots north of Foothill Boulevard, the foundation will likely need stepped footings and improved drainage at the downslope edge. We include that in the written price from the beginning.
Trusted Brands We Service in La Verne
We’re authorized to build with Abodu, Cover, Dvele, and other leading prefab systems, and we use James Hardie cladding when the design calls for it. For La Verne customers, that means faster framing on panelized projects and materials that hold up through the hot, dry summers and the winter rains that roll off the San Gabriel foothills. Because we coordinate both prefab delivery and site work, you’re not stuck managing a manufacturer and a contractor separately. It’s one team, one schedule, and one written price.
Common Home Addition Contractor Problems We See in La Verne Homes
- Slope-blind pricing. La Verne’s foothill edge and older alluvial-fan lots mean many additions on the north side of town face slope-drainage and compaction issues that don’t arise on the flatter grid streets downtown. This regularly changes foundation design and cost before framing even starts, and a contractor who prices without a soil or slope review will understate the job.
- Setback surprises at plan check. Treating an addition as a simple bump-out before confirming setback and lot-coverage limits against the existing house footprint is the fastest way to a rejected plan. Older lots near downtown were built to older codes, and the structure you’re adding to may already be closer to the property line than current rules allow.
- Prefab without full site prep. Assuming a prefab panel or shed-shell approach (Abodu, Cover, Boxabl, Tuff Shed) removes the need for full site, foundation, and utility work will wreck a schedule. The shell is one part of it; the site, grading, utilities, and inspections remain, and someone has to own that work end to end.
- Roof-tie failures on 1950s ranch houses. Many La Verne homes from the post-war boom have shallow-pitch roofs and original rafter framing. Tying a new roofline into those rafters incorrectly leads to leaks at the transition. We open the connection, inspect what’s actually there, and engineer the tie-in before we close it up.
Pricing for Home Addition Contractor in La Verne, CA
A site-built addition in La Verne generally runs $250 – $400 per square foot, with smaller rooms like bathrooms landing at the higher end of that range. A bathroom addition runs $45,000 – $85,000. A bedroom addition runs $90,000 – $140,000. A primary suite with bath runs $120,000 – $150,000. What moves the number most on La Verne lots? Slope and soil, because a stepped footing and drainage correction can add $8,000 – $20,000 before framing begins. Upgraded finishes, new electrical panel capacity, and sewer line replacement also move the price. We give you line-item pricing in writing, not a square-footage guess you have to trust.
Call (903) 568-7222 for a free estimate. The number you see is the number you’ll pay, and we put it on paper before work starts.
We Also Serve Cities Near La Verne
Our crews work across the eastern San Gabriel Valley, including San Dimas, Claremont, Glendora, and Montclair. If you’re a few minutes outside La Verne, the same written-price guarantee and 365-Day Done Right Promise apply. You can also learn more about our full scope as a Home Addition Contractor, or see how we approach work specifically in La Verne on our local city page.
Serving La Verne, CA - Our Local Coverage Area
We’re based in the La Verne 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 La Verne
Most La Verne additions take 4 to 7 months from the first walk-through to final inspection. The variables are plan check at the city, any slope-related foundation design, and whether you’re going site-built or panelized. A simple bathroom addition on a flat lot can finish in about 4 months. A sloped north-side primary suite will trend closer to 7. Call (903) 568-7222 and we’ll give you a realistic calendar for your specific lot.
Yes. Any addition that adds conditioned square footage, modifies the roof structure, or touches plumbing and electrical needs a La Verne building permit and inspections at rough and final stages. We pull the permits, schedule the inspections, and stand with the inspector on walk-through day. Unpermitted work is a liability when you sell, and it’s not worth the short-term savings.
Slope and soil on La Verne’s north-side alluvial-fan lots are the biggest hidden cost driver. A stepped footing, drainage correction, and compaction work can add $8,000 – $20,000 before framing starts. After that: sewer line condition, electrical panel capacity, roof-tie complexity, and finish level. We price all of it up front.
Yes, a prefab system from Abodu, Cover, or Dvele can cut weeks off framing and finish work compared to fully site-built construction. But the foundation, grading, utilities, and inspections still happen on site, on your lot’s timeline. We manage the prefab delivery and the site work as one scope, so the schedule savings actually materialize. Call (903) 568-7222 to compare prefab versus site-built for your project.
Very little, if the walk-through was honest and the plans are complete. The known unknowns on a La Verne addition are hidden foundation conditions, old cast-iron drain lines, and rotted rafter tails at the roof tie-in. We inspect for those before pricing. If something genuinely unforeseen appears inside a wall, we show you photos, give you a written change order, and get your approval before proceeding. You’ll never get a surprise invoice after the fact.
Written by Troy Eastman, Owner at Benson ADU Builders, serving La Verne with written pricing and the 365-Day Done Right Promise.


