







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 Bonita
A home addition in Bonita is rarely just “adding square footage.” It means opening up a 1960s ranch or a 1970s Spanish-influenced home and dealing with what’s actually inside those walls: aluminum branch wiring, undersized 2×4 framing, failed waterproofing at the stem wall, and yes, a septic system that was sized for a three-bedroom house forty years ago. We’re Lodgewick ADU San Diego, and our crews work in Bonita every week. We know the lots, we know the setbacks, and we know what the county will ask for once the permit is pulled. If you’re planning a room addition, second-story suite, or garage conversion in Bonita, call (619) 376-2760. We’ll give you a written price before any work starts.
Why Lodgewick ADU San Diego Is Bonita’s Preferred Home Addition Contractor Company

Bonita homeowners have a low tolerance for surprises. Too many have already been through a remodel where the price “changed at the door” or a crew never showed when they said they would. That’s why the way we operate here matters. Every project runs under The Kingswell Guarantee: a written price before work begins, a defined arrival window, a clean job site, and a written guarantee on every build, with a free return visit if the work fails within 365 days. That’s the 365-Day Done Right Promise, and you get it in writing.
Russ Delmar leads our Bonita projects. He’s walked dozens of lots in Bonita Woods, Bonita Highlands, and along Sweetwater Road, and he’ll tell you the same thing every time: the quote doesn’t mean anything until someone has looked at your framing, your panel, and your septic system. That’s the inspection-first approach, and it’s how we keep change orders honest. When we open a wall and find something the original quote didn’t account for, we stop. We show you what we found. We price it in writing. You approve it before we touch anything else. That’s The Kingswell Way, and it’s the only way we build in Bonita.
Garage Addition Contractors in Bonita
Garage Addition Contractors in Bonita work with a specific set of constraints you won’t find in Chula Vista or National City. Many Bonita garages sit on lots with private wells and septic systems, and converting a garage into living space almost always triggers a conversation with the county about septic capacity. If your system was sized for a three-bedroom home in 1972, adding a bedroom and bathroom to the garage means expanding the leach field or upgrading the tank. That’s a $20,000 to $30,000 reality that a flat-quote contractor will “discover” after walls are open. We price it into the contract from day one, as a written allowance.
Structural Reality of Bonita Garages
Most Bonita garages built before 1980 were never intended to carry a finished ceiling, insulation, drywall, or a ducted mini-split. The rafters are often undersized, the slab has no moisture barrier, and the stem wall waterproofing failed years ago. We inspect the roof framing and foundation before we quote, and we write the reframing numbers into the price. No vague “we’ll see when we get there” language.
Converting Without Losing the Horse Trailer
Some Bonita homeowners want to convert half the garage but keep covered parking for a horse trailer or an RV. That’s common in the equestrian-zoned neighborhoods. We design additions that preserve the clear span you need, and we work within the county’s setback requirements for accessory structures. You don’t have to choose between an ADU and your trailer.
Bathroom Addition Contractor in Bonita

A Bathroom Addition Contractor in Bonita is often the first call on a project that starts as “we need a second bathroom” and ends as a full primary-suite addition. Adding a bathroom to a Bonita home isn’t just framing and tile. It’s verifying that the drain line can reach the septic tank, sizing the vent stack correctly, and, on some of the older ranch-style homes, replacing cast-iron drain piping that’s been in the ground since the Eisenhower administration. We handle all of it, and we price it before we start.
Septic Capacity and Bathroom Count
County code ties the allowed number of bedrooms and bathrooms to your septic system’s design capacity. Adding a full bathroom to a Bonita home on a private well and septic system can trigger a leach field expansion. We’ll pull the septic as-built records before we finalize the quote, so you know the real number before the permit is filed.
Wet Walls and Waterproofing
Bonita’s inland climate means hot, dry summers and occasional heavy winter rains. Any bathroom addition needs a properly flashed roof intersection, waterproofed stem wall, and a shower pan that’s tested before tile goes down. We write the waterproofing schedule into the contract, and we photograph every step. If something fails within the 365-day guarantee period, we come back and fix it. Free.
Trusted Brands We Service in Bonita
We work hands-on with prefab and panelized building systems that fit Bonita’s lots and timelines. That includes Plant Prefab for precision-built wall and roof panels, Tuff Shed for garage-to-ADU shell conversions, and James Hardie siding and trim that holds up to Bonita’s dry heat and occasional hard rain. We stock common replacement parts locally and can get manufacturer-specific materials to your Bonita job site fast. If you already have a design or a prefab kit in mind, we’ll quote the site work, foundation, utilities, and finish work separately, so you see exactly what each part costs.
Common Home Addition Contractor Problems We See in Bonita Homes
- Septic surprises after walls are open. A contractor who doesn’t check septic as-builts before quoting will hand you a $20,000 to $30,000 change order mid-project. We verify septic capacity before the permit goes in.
- Aluminum branch wiring in 1950s and 1960s homes. Opening a wall for an addition means bringing the exposed circuits up to current code. That’s an AFCI retrofit, and we write it into the allowance, not a surprise invoice.
- Equestrian-overlay stop-work orders. In neighborhoods like Bonita Woods, additions that block horse turnouts or cut into mature oak root zones can trigger a county stop-work order. We check the overlay requirements before we draw, not after the foundation is poured.
- Undersized 2×4 framing and failed waterproofing. Homes built from the 1950s through the 1980s often have 2×4 exterior walls that don’t meet current energy code, and stem wall waterproofing that failed years ago. We inspect first, then price the fixes in writing.
Pricing for Home Addition Contractor in Bonita, CA
We Also Serve Cities Near Bonita
Our crews serve Bonita plus the surrounding South Bay communities: National City, Chula Vista, Lemon Grove, and La Mesa. If you’re looking for a Home Addition Contractor in any of these areas, the same written-price guarantee applies. And if you want to see how we handle Bonita’s septic and equestrian-overlay challenges specifically, take a look at our Home Addition Contractor in Bonita coverage.
Serving Bonita, CA - Our Local Coverage Area
We’re based in the Bonita 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 Bonita
It depends on your current septic design capacity and the county’s bedroom count on the permit. Many Bonita systems were sized for the original 1950s – 1980s bedroom count, and adding a bedroom can push you over. We pull the as-built records and we’ll know before we quote, not after we dig. Call (619) 376-2760 and we’ll check your address.
Any circuit we expose during the addition has to be brought up to current code. That means AFCI protection on branch circuits, and often replacement of the aluminum wiring in the affected areas. We write that allowance into the contract from the start, so there’s no surprise bill. It’s part of the inspection-first approach we use on every Bonita project.

In many cases, yes. Bonita homes built before modern seismic codes often need foundation bolting, cripple wall bracing, or hold-down anchors added before a second story goes on. We bring in a structural engineer during the quote phase, so you know the retrofit scope and cost before the permit is filed.
Plan check for an addition in an equestrian-overlay zone in Bonita usually runs 6 to 12 weeks, depending on whether the project requires a discretionary review. We handle the drawings, the overlay checks, and the submittals, and we’ll tell you upfront if your project is headed for the longer timeline.
Yes, in most cases. We design the conversion to keep a clear-span bay for your trailer or RV, and we work within the county’s setback and coverage limits for accessory structures. On equestrian-zoned lots, we also make sure the addition doesn’t encroach on required turnout areas or mature tree root zones. Call (619) 376-2760 for a free estimate and we’ll walk the lot with you.
Written by Russ Delmar, Owner at Lodgewick ADU San Diego, serving Bonita and the surrounding South Bay communities.









