Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Fast, Reliable Home Additions & ADU Across Canoga Park
If you’re weighing a room addition or an ADU in Canoga Park, the honest starting number is somewhere between $45,000 and $130,000 depending on scope, and the biggest variable isn’t the drywall. It’s whether the plan accounts for what’s underneath and around your house before framing starts. Canoga Park sits roughly three to four miles from the 1994 Northridge earthquake epicenter, which means a meaningful share of the 1950s-to-1970s stucco ranches and soft-story apartment buildings here carry seismic damage history, unretrofitted cripple walls, or LA City retrofit obligations that a neighboring Valley city wouldn’t even put on the permit checklist. We live with that reality on every job, and it shapes how we quote, plan, and build here. Call (877) 610-1318 and you’ll get Tom Barrett or one of his sons, not a call center, and we’ll talk straight about what your project actually needs.
Why Barrett & Sons Construction Is Canoga Park’s Preferred Home Additions & ADU Company
Barrett & Sons Construction is the owner-operated, name-on-the-truck alternative to the national outfits that quote one number on the phone and hand you a different bill at the door. Tom Barrett founded the company in 1998, and his sons run the crews. When we say “we,” we mean people whose last name is on the van. Every eligible job in Canoga Park gets permits pulled and inspections signed, because the last contractor many of our customers used told them permits were optional. Tom publishes his name, his address, and his license number. Look them up before you sign anything. A live person answers our phone 24 hours a day, seven days a week, and every price change arrives as a written change order before a single nail moves.
In Canoga Park specifically, our crews know which parcels in the northern 91304 ZIP fall inside the CalFire Very High Fire Hazard Severity Zone, because we’ve stood at enough plan-check counters to watch a reviewer flag non-compliant soffit venting or T1-11 siding mid-review. That’s a four-week delay you shouldn’t have to learn about the hard way. We also know the soft-story retrofit triggers on 1960s and 1970s garden apartment dingbats with tuck-under parking, and we know what the slab-on-grade foundations under the old ranches look like once you strip the floor and find the hairline seismic cracking. That’s local knowledge that only comes from doing the work here.
Our Home Additions & ADU Services in Canoga Park
Our Home Additions & ADU team handles the full range, from a permitted garage conversion to a detached unit built from the slab up. Here’s how the main pieces typically break down for Canoga Park homeowners.
ADU Design & Permitting
Before we frame anything, we sit down with your parcel map, the LA City zoning rules for Canoga Park, and your 91303, 91304, 91305, or 91309 address, and figure out exactly what you can build. In the western San Fernando Valley heat pocket where Canoga Park sits, summer highs routinely hit 100 to 108°F, so we also plan for window orientation, insulation depth, and mechanical sizing that a coastal contractor would get wrong. If your parcel touches the Very High Fire Hazard Severity Zone boundary, we draft for Chapter 7A from day one, not as a plan-check surprise.

Garage Conversion ADU
Converting an attached or detached garage is usually the fastest path to a rentable unit in Canoga Park, and the range here typically runs $30,000 to $80,000. The complication that comes up most often is the original slab. Many 1950s-era garages in this area were poured thinner than today’s code requires, and adding a living space on top of a slab with hairline seismic cracking means we often saw-cut, dowel, and pour a thickened edge or a full overlay. That’s a written change order if the demo reveals it, not a surprise invoice at the end.

New Detached ADU
A new detached ADU in Canoga Park typically lands between $90,000 and $220,000 depending on size, finishes, and site work. We handle the full build: foundation, framing, roofing, rough electric, plumbing, drywall, kitchenette, bath, and the final inspection sign-off. If your lot backs up toward the Simi Hills interface, we’ll spec ignition-resistant siding and ember-resistant vents that meet the fire code before the plan reviewer asks about them. We also keep the roofline and setback in scale with the existing ranch house, because an ADU that fights the neighborhood looks like an afterthought.

Junior ADU & Interior Conversion
A junior ADU is often the smartest move for a Canoga Park homeowner who wants rental income without a full detached build. We convert an existing bedroom or bonus room into a self-contained junior unit with its own entrance, kitchenette, and bath access, and we handle the owner-occupancy documentation and permit path that LA City requires. These projects tend to run toward the lower end of the addition range, but we will not quote you a skinny number just to get the job and then hand you a change order when the wall comes open. You’ll see the real scope on paper first.

What happens when you call
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A real person answersNo phone trees - you reach a local pro.
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You get an upfront price rangeHonest numbers before anyone is dispatched.
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A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in Canoga Park
We carry materials you can look up, not mystery brands off a van. On Canoga Park addition and ADU jobs, we regularly install Simonton windows with the right solar heat gain coefficient for our 100-plus-degree summers, and Ply Gem siding and trim where fire-rated cladding is required near the Simi Hills edge. PGT impact-rated products show up on jobs where the client wants a little more than code minimum. Because our crews work Canoga Park weekly, we can pull the right components quickly and we know which suppliers actually stock the fire-rated venting and seismic hardware this part of the Valley demands. When you call, we’ll tell you exactly what we’re proposing and why, and you can look up every brand name before you approve a dollar of it.
Common Home Additions & ADU Problems We See in Canoga Park Homes
- Soft-story and cripple-wall exposure. The 1960s and 1970s dingbat apartments and the older single-story ranches in Canoga Park often predate modern seismic codes. When we open the walls on an addition, we regularly find cripple walls that were never bolted or braced, and LA City’s retrofit ordinances mean that has to get fixed before or alongside our work.
- Original slab-on-grade foundations with seismic cracking. Many post-WWII homes in 91303 and 91304 sit on slabs that have carried 30-plus years of Valley heat cycles and at least one major earthquake. Adding square footage means we verify the slab’s condition first, and we document what we find in writing.
- Fire-zone compliance surprises. The northern fringe of the 91304 ZIP falls inside CalFire’s Very High Fire Hazard Severity Zone. If your plans don’t address Chapter 7A requirements for ignition-resistant siding, Class A roofing, and ember-resistant vents from the start, you can lose weeks at plan check.
- Roof dead load from repeated re-roofing. Many Canoga Park composition roofs have been re-roofed multiple times over the decades without tearing off the old layers. That added dead load sits above the original framing specs, and it matters when we’re tying a new addition’s roofline into the existing structure.
Pricing for Home Additions & ADU in Canoga Park, CA
For a Canoga Park home addition, plan on a working range of $45,000 to $130,000. A garage conversion ADU typically lands between $30,000 and $80,000, while a new detached ADU runs $90,000 to $220,000 depending on size and site conditions. What moves the number the most in Canoga Park specifically is seismic retrofit scope: if your foundation or cripple wall needs bolting and bracing before we frame, that’s real work and it has to be on the table from the beginning. Fire-zone requirements in the northern 91304 section can also add material costs that don’t exist two miles south. Here’s the straight part: every scope, every allowance, every price change arrives as a written change order before work happens. No surprise invoices. Call (877) 610-1318 for a free, written, line-item estimate, and we’ll show you exactly where the money goes.
We Also Serve Cities Near Canoga Park
Our crews work Canoga Park every week, and we also cover the surrounding communities: West Hills, Woodland Hills, Chatsworth, and Northridge. If you’re on the edge of 91304 where it bumps against West Hills, or just north of the 91303 line near Woodland Hills, we’re minutes away. For the full picture on what we do across the Canoga Park area, or if you’re also weighing a kitchen project, see our Kitchen Remodeling in Canoga Park page, and when it’s a bath, our Bathroom Remodeling in Canoga Park page covers that trade too.
Serving Canoga Park, CA - Our Local Coverage Area
We’re based in the Canoga Park 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 - Home Additions & ADU in Canoga Park
We schedule estimates in Canoga Park within a few days depending on the season, and we’ll give you a firm appointment window. For a written, line-item estimate on a home addition or ADU in Canoga Park, call (877) 610-1318 and we’ll set it up directly. Tom or one of his sons will walk the site with you, and if there’s a soft-story or fire-zone condition that changes the scope, you’ll see it in writing, not after the demo starts.
Yes. We serve all four Canoga Park ZIP codes: 91303, 91304, 91305, and 91309. That includes the older ranch-home blocks east of Topanga Canyon Boulevard, the garden apartment streets near Canoga Avenue, and the northern 91304 section that rolls up toward the Simi Hills fire-zone boundary. If you’re anywhere in Canoga Park, we’re local.
Yes. When we open a wall or slab and find a structural problem the previous owner never addressed, we stop, document it, and bring you a written change order with the fix and the cost before we continue. That’s the whole point of written change orders: no surprise invoices at the end, and every structural repair is permitted and inspected. Call (877) 610-1318 and we’ll explain exactly how that works on your project.
Canoga Park pricing generally runs in the same range as Woodland Hills, West Hills, Chatsworth, and Northridge, because we’re drawing from the same labor pool and the same suppliers. The local difference is seismic and fire-zone scope. A home on the northern edge of 91304 can carry material and engineering costs that a comparable home in another Valley neighborhood won’t, and we’ll tell you about that on the first visit, not the fourth week of construction.
Every job we do carries the written 90-Day Done Right Promise: if it’s not done right, Tom comes back and makes it right, one call. It’s on the contract, not buried in fine print. Beyond that, we pull permits and get inspections signed on every eligible job, and the sign-off is your independent verification that the work passed. Call (877) 610-1318 for a free estimate, and we’ll put the whole agreement in writing before any work begins.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving Canoga Park and the San Fernando Valley since 1998.







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