A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateFast, Reliable ADU Builders Across Covina
Adding an accessory dwelling unit in Covina typically costs between $185,000 and $390,000 for a detached unit, while a junior ADU conversion usually lands between $85,000 and $145,000. Those numbers shift based on your lot, your garage, and what the city plan check flags. We know Covina’s housing stock because we work it every week: the pre-1960 tracts near Downtown, the alley-accessed parcels off Citrus Avenue, and the R-1 lots where a detached unit needs a variance before a single wall goes up. Call (903) 568-7222 and we’ll walk you through what your specific lot is actually going to need.
Why Benson ADU Builders Is Covina’s Preferred ADU Builders Company
Covina homeowners call us because we put the price in writing before work starts, then stand behind it through final inspection. That’s not a sales line. Our ADU Builders team works from The Relay Visibility Guarantee: a written price, a 365-Day Done Right Promise, and a free second visit if any covered repair fails within a year. No verbal estimate that balloons after demo day.
We also show up the way you’d expect a modern contractor to. Background-checked, uniformed technicians on every job site. A live person answers the phone around the clock, every day. And when we scope a Covina project, we scope the lot, not just the unit. That means surveying the existing garage before quoting a turnkey price, because a 1948 detached garage with asbestos siding changes the budget and the schedule. Most contractors figure that out after the contract is signed. We figure it out during the estimate.
Troy Eastman leads our ADU work across Covina. He’s the person who reviews your lot sketch, flags the setback issue before plan check does, and signs off on the written price. That accountability is why Covina homeowners keep referring us to their neighbors on Azusa and Citrus.
Detached ADU in Covina
A detached ADU in Covina starts with your lot’s constraints, not a catalog floor plan. On older R-1 parcels near the downtown core and up against the foothill slope, rear setbacks, alley frontage, and a non-conforming garage footprint often determine whether the unit gets permitted as drawn or needs a variance. We scope for those issues in the estimate, because that’s where Covina bids go sideways. A typical detached ADU here runs $185,000 to $390,000, with the site work – demolition, grading, trenching, slab pour – frequently driving the final number more than the structure itself.
Covina’s lots were largely platted and built before 1960. That means mature citrus-rooted soils that heave, shared sewer laterals that need scoping before you trench, and garages that were never built to current setback rules. If your detached ADU is going where an old garage now stands, the demo permit, slab re-pour, and possible asbestos abatement all land in the budget before framing starts. We include those line items in writing, so the number you sign is the number you pay.
Garage-to-ADU conversions
Converting a detached garage beats demo-and-rebuild only if the slab is sound, the walls are square, and the roof framing can carry a second story or a vaulted ceiling. In Covina’s pre-1960 stock, we usually find the slab is cracked or undersized for living space. When that’s the case, the honest answer is a full teardown and a new panelized build – which is often cheaper than trying to retrofit a failing structure.
Setback and variance work
Covina plan check flags rear and side setbacks more often than most homeowners expect, especially on corner lots with alley frontage. If your garage sits closer to the property line than current code allows, the city may require a variance before the ADU can be sited. We handle the survey, the re-submittal, and the re-siting. It adds time, but it’s better to know in week one than week twelve.
JADU in Covina
A JADU in Covina is the fastest path to a legal rental or family unit, because it works within your existing home’s footprint. Think of a converted back room, a finished attached garage, or a bonus space with its own exterior door. We permit the JADU as its own submittal – a common mistake is bundling it with a detached ADU permit and stalling the smaller unit while the larger one sits in plan check. A JADU conversion here typically runs $85,000 to $145,000 depending on whether you’re adding a kitchenette, a bath, and separate egress.
What makes a Covina JADU realistic is the housing stock. Many pre-1960 homes have a back room or service porch that was never counted as living space but already has exterior access. That’s a head start. We bring it up to current code – egress window, fire separation from the main house, separate smoke and CO detection – and get it permitted as a legal dwelling. On a corner lot off Citrus Avenue near Downtown Covina, we handled a JADU conversion of an existing back room while a detached ADU was still in plan check. The JADU passed final inspection as a separate permit while the larger unit waited on a setback redesign. That sequencing matters.
Back room and attached garage JADUs
The first question is whether the space has its own entrance without cutting into your living room. The second is whether the garage slab and walls can support insulation, drywall, and a conditioned space without a full rebuild. In Covina’s older stock, attached garages often weren’t built to residential insulation standards, so part of the budget goes to wall furring, ceiling insulation, and sealing the old slab against moisture.
JADU plus detached ADU on one lot
California allows both a JADU and a detached ADU on the same single-family lot, and Covina is no exception. The catch is permitting them separately, which changes your inspection calendar and your construction sequence. We map that timeline in the written estimate so you know when each unit gets its own plan check, its own inspection, and its own final sign-off.
Trusted Brands We Service in Covina
Benson ADU Builders is authorized to build with Cover, Dvele, and Boxabl panelized and prefab systems, along with James Hardie cladding products. For Covina homeowners, that means you’re not stuck with a single take-it-or-leave-it floor plan. You can compare the precision of a Cover panelized shell against a Dvele high-performance envelope, or explore Boxabl’s factory-built modules. Each brand has different lead times, cost points, and design constraints, and we walk you through the trade-offs in plain English. Because we work with these manufacturers directly, Covina projects don’t wait on parts or panels the way site-built framing sometimes does.
Common ADU Builders Problems We See in Covina Homes
- Quoted a turnkey price before checking the garage. Covina’s pre-1960 garages often have asbestos siding, a shared sewer lateral, or a slab that has to come out. If your first bid didn’t include a site walk that checked those three things, the number will move. Ours doesn’t.
- Alley frontage and easements trigger setback variances. Narrow R-1 lots with alley access behind them don’t meet the standard rear setback assumption. The city flags it at plan check, and suddenly the ADU has to be re-sited. We survey for this before we quote.
- Mature citrus-rooted soils heave slabs and crack driveways. Covina’s older lots were citrus groves before they were neighborhoods. Root systems decay and shift, which means your new slab needs proper re-grading, and your utility trenching may run into more obstruction than a trench on newer Inland Empire fill. Budget for it up front.
- Permitting a JADU and detached ADU as one bundle stalls both. Each is a separate submittal with its own plan check and inspection sequence. Bundling them saves one trip to the counter and costs months. We file them separately and sequence the builds so the smaller unit finishes first if that’s what the budget needs.
Pricing for ADU Builders in Covina, CA
A detached ADU in Covina runs $185,000 to $390,000. A JADU conversion lands between $85,000 and $145,000. The biggest cost drivers on Covina lots are site work: garage demolition, slab re-pour, grading, and utility trenching through old citrus-rooted soil. A variance adds engineering time and plan check fees, but it’s a lot cheaper than rebuilding a unit the city won’t sign off on. We write every price before work starts, and what changes a price is a change in scope – not a surprise at the door. If your garage has asbestos siding, you’ll see the abatement line item before you sign. If your lot needs a variance, that’s in the estimate too. Call (903) 568-7222 to schedule a free, written estimate.
We Also Serve Cities Near Covina
Our crews cover Covina and the surrounding San Gabriel Valley communities, including Azusa, West Covina, Baldwin Park, and Glendora. If you’re in one of those areas, the same written pricing and 365-Day Done Right Promise applies. See our ADU Builders in Covina page for the full service area breakdown.
Serving Covina, CA - Our Local Coverage Area
We’re based in the Covina 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 ADU Builders in Covina
Because the first bid probably didn’t account for what’s under the garage and in the ground. Covina’s pre-1960 lots commonly have asbestos siding, shared sewer laterals, and citrus-rooted soils that heave. A real site visit includes a slab check, a lateral scope, and a survey against current setbacks. Our written price includes all of it from the start, so the only thing that changes the number is a change in scope you request. Call (903) 568-7222 for an estimate that holds.
Often yes, especially on corner lots, alley-accessed parcels, or properties where the existing garage sits closer to the property line than current code allows. Covina plan check will flag the rear or side setback, and you can’t frame until it’s resolved. We handle the survey and re-submittal as part of the project, and we flag the variance during the estimate so it doesn’t surprise you. Call (903) 568-7222 if you want us to check your lot before you spend a dollar on plans.
Yes, and on many Covina lots it’s the smarter first move. A back room or attached garage with its own exterior door can often become a legal JADU with an egress window, fire separation, and a kitchenette. The budget is far below a detached ADU – $85,000 to $145,000 in Covina – and the permit is its own submittal, so it doesn’t wait on the larger unit’s plan check. Call (903) 568-7222 for a free evaluation of what your existing space can legally become.
Plan for nine to fourteen months on a detached ADU in Covina, and four to seven months on a JADU. The variables are plan check turnaround, variance hearings if your lot needs one, and utility trenching through old soils. A setback redesign alone can add six weeks, as we saw on a corner lot off Citrus Avenue near Downtown Covina. We give you a written calendar at contract, and we update it in real time through our project tracking. Call (903) 568-7222 and we’ll scope your lot and give you an honest timeline.
We’re authorized to build with Cover, Dvele, and Boxabl panelized and prefab systems, and we finish exteriors with James Hardie cladding. Each brand suits different lots: Cover’s precision panels work well on tight Covina lots, Dvele’s high-performance envelope handles the foothill temperature swings, and Boxabl’s factory-built modules compress on-site construction time. We’ll show you the trade-offs and the costs for each on your specific parcel.
Get a Written ADU Price for Your Covina Lot
If you’re thinking about an ADU on your Covina property, start with a real site walk and a written price – not a verbal range that shifts once the garage door comes off. Call (903) 568-7222 and we’ll survey your lot, check your setbacks, scope your sewer lateral, and give you a written estimate that holds. That’s how we work in Covina, and it’s why our customers know the number before the shovel hits dirt.
Written by Troy Eastman, Owner at Benson ADU Builders, serving Covina and the San Gabriel Valley.
