Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Before
After
Before
After
Before
AfterFast, Reliable Home Additions & ADU Across El Granada
You live in El Granada, where adding square footage isn’t just a design decision; it’s a permitting project that starts with the California Coastal Commission. Most room additions and ADUs here require a San Mateo County Coastal Development Permit before anyone swings a hammer. It’s a dual-track process most Bay Area contractors never face, and it’s exactly why our Home Additions & ADU team handles the paperwork from day one. If you’re considering a garage conversion off Coronado Street or a detached ADU near Avenue Alhambra, we can walk you through the actual sequence: coastal review, county building permit, then construction. Call (877) 610-1318 to talk through your project with someone who knows El Granada’s rules – a live person answers, 24/7.
Why Barrett & Sons Construction Is El Granada’s Preferred Home Additions & ADU Company
We’ve spent the last 29 years in San Mateo County, and El Granada work has a rhythm you don’t learn from a distance. Homeowners here deal with a coastal permitting process that would make a Burlingame contractor’s head spin. We know the County Planning & Building Department’s coastal review workflows because we work within them constantly, not occasionally. That means fewer stop-work orders, fewer surprise delays, and a realistic timeline from your first call to final inspection.
Tom Barrett founded this company in 1998, and his sons run the crews. When you hire us for a home addition in El Granada, you’ll see the same faces from the first estimate to the final walkthrough – not a rotating cast. Our 90-Day Done Right Promise is written on every contract: if something isn’t right, one call brings Tom back. That’s not a marketing line; it’s how we’ve worked for nearly three decades.
El Granada homeowners often tell us about previous experiences with out-of-area crews who didn’t understand coastal construction. Salt air, the marine layer, aging wood-frame homes on compact lots – these aren’t footnotes here; they’re the whole story. We spec materials for this environment from the first drawing, not as an afterthought when a problem shows up at inspection.
Our Home Additions & ADU Services in El Granada
ADU Design & Permitting
An ADU in El Granada starts before any design work: you need to know whether your parcel triggers a Coastal Development Permit. In this unincorporated community, that answer is almost always yes. We handle the pre-application, the coastal review, the county building permit, and the design drawings as one package. A typical El Granada ADU runs $90,000 to $220,000 all-in, and our written scope covers every line item so you’re never surprised by a change order that wasn’t on paper first.
Garage Conversion ADU
Many El Granada homes from the 1950s and 1960s have detached garages on lots that started as 25-foot-wide parcels. Converting one into a rental or family unit usually lands between $30,000 and $80,000, depending on condition. The catch here is coastal review: some El Granada garage conversions trigger additional setbacks or drainage requirements because of the Coastal Zone overlay. We work through San Mateo County’s process before you spend a dollar on framing. Converting an old garage in El Granada also means confronting what’s in the walls – knob-and-tube wiring, uninsulated framing, and slabs poured without vapor barriers are common.
New Detached ADU
Building a new detached ADU in El Granada gives you a clean slate, but the Coastal Development Permit process adds months that other Bay Area cities don’t face. We’re not going to sugarcoat it. What you get in return is a structure we can spec correctly from the foundation up: hot-dipped galvanized hardware, moisture-resistant sheathing, and exterior finishes suited to salt-laden air. $90,000 to $220,000 is the real-world range here, and we’ll show you exactly where each dollar goes before we sign a contract.
Junior ADU & Interior Conversion
A junior ADU works well inside existing El Granada homes where attics, bonus rooms, or attached garages can be converted without changing the footprint. These projects range from $45,000 upward and often move faster because they don’t always require the same Coastal Commission review triggers as a detached structure. That said, don’t assume anything: we verify the permit path for your specific parcel and your specific conversion before we quote anything.
What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
- 2
You get an upfront price rangeHonest numbers before anyone is dispatched.
- 3
A background-checked tech heads outLicensed & insured, dispatched right away.
- 4
You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in El Granada
We install windows and doors from Simonton, PGT, and CGI – brands built for coastal conditions. In El Granada, that matters more than in Millbrae or Hillsborough. Salt-laden marine air corrodes cheap aluminum and delaminates low-grade laminates within a few winters. We also keep the parts pipeline simple: if a Simonton window arrives with a damaged sash or a PGT impact door needs a replacement gasket before inspection, we handle it without slowing your project down. You’ll never hear us push an off-brand alternative to hit a lower price; we install materials you can look up and verify yourself.
Common Home Additions & ADU Problems We See in El Granada Homes
- Delaminated OSB sheathing on ocean-facing walls. Standard oriented strand board starts swelling and losing structural integrity within one wet season under El Granada’s marine layer. We spec moisture-resistant ZIP System panels or plywood as the baseline, not an upgrade.
- Corroded fasteners and connectors in load-bearing framing. Uncoated steel doesn’t survive the salt-laden air here for long. We use hot-dipped galvanized or stainless hardware throughout every addition and ADU we build in El Granada.
- Coastal Development Permit stoppages. Plenty of El Granada homeowners start with a contractor who doesn’t pull the Coastal permit, and construction halts when San Mateo County shows up. We pull every permit before work begins and route everything through the county’s coastal review process ourselves.
- Inadequate drainage and slope work on bluff-facing parcels. El Granada’s bluff and hillside lots move water in ways flat-lot builders don’t expect. Improper drainage on one lot floods the neighbor downhill. We address grading and drainage as part of every addition’s scope, in writing.
Pricing for Home Additions & ADU in El Granada, CA
Here’s what you can expect to spend on home additions and ADUs in El Granada, based on current project costs in this market, including the coastal permitting path:
| Project Type | Typical El Granada Range |
|---|---|
| ADU Construction | $90,000 – $220,000 |
| Garage Conversion | $30,000 – $80,000 |
| Home Addition | $45,000 – $130,000 |
These ranges include the San Mateo County coastal review and building permit processes, which add both time and cost compared to inland Bay Area cities. Your specific project cost depends on parcel slope, foundation condition, the Coastal Development Permit triggers on your lot, and finish selections. We provide free written estimates with line-item pricing, and every change order is a written document you approve before work proceeds. No surprises at the end. Call (877) 610-1318 to schedule your free estimate in El Granada.
One thing we want to say plainly: living in El Granada means your project answers to the Coastal Commission, not a city hall. That’s not a reason to avoid the work; it’s a reason to hire someone who’s done it repeatedly. We have.
We Also Serve Cities Near El Granada
Our crews serve the broader San Mateo County coast and Peninsula, including Half Moon Bay, Hillsborough, Millbrae, and Burlingame. If you’re in El Granada or any of these nearby communities, our El Granada service area coverage means a local crew, local knowledge, and a 24/7 live answer when you call (877) 610-1318.
Serving El Granada, CA - Our Local Coverage Area
We’re based in the El Granada 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 El Granada
Nearly every home addition or ADU in El Granada requires a San Mateo County Coastal Development Permit because the entire community sits within the California Coastal Zone. There are narrow exemptions for some interior-only work, but any structural change, footprint change, or new detached structure will almost certainly trigger the coastal review. We verify the exact permit path for your parcel before quoting your project. Call (877) 610-1318 and we’ll check your address against the county’s coastal overlay maps.
Yes, but bluff-facing garage conversions in El Granada often trigger additional drainage, setback, and geological review through the county because of erosion and slope-stability requirements in the Coastal Zone. The conversion itself may cost $30,000 to $80,000, and the coastal review can add months to the timeline. We’ve done these projects and we know the specific documentation the county wants. A free estimate will show you the full sequence.
Yes, and in El Granada the case for replacement is stronger than inland. Original single-pane windows from that era leak heat, fog constantly in the marine layer, and allow moisture intrusion that feeds rot in surrounding framing. For a room addition, replacing adjacent windows with Simonton, PGT, or CGI coastal-rated units modernizes the whole home’s envelope. Window replacement projects in this market typically run $4,500 to $15,000 depending on count and glass package.
It can, if the addition isn’t engineered and documented properly. A second-story addition changes load paths, and the original builder’s warranty typically covers the original structure only. That’s why we provide stamped engineering for the entire load path, not just the new framing, and document every modification. The goal is protecting your original warranty on untouched portions while extending a clean warranty on everything we build. Our 90-Day Done Right Promise covers our work in writing.
In El Granada, plumbing and electrical rough-in in ADUs and additions must meet San Mateo County’s coastal moisture and corrosion standards, which are stricter than inland code. We use hot-dipped galvanized hardware, stainless fasteners, and moisture-resistant sheathing as the baseline, and we specify wiring and junction boxes rated for high-humidity, salt-laden air. These choices prevent the callbacks that out-of-area crews create by using standard inland materials on the coast.
Get Your Free Home Addition or ADU Estimate in El Granada
If you’re planning an ADU, garage conversion, or room addition in El Granada, start with a conversation, not a surprise. We’ll review your parcel, walk the coastal permit path, and put every scope and allowance in writing before you commit. Tom Barrett’s name, address, and license number are published – look them up. One call brings a live person, 24/7. Call (877) 610-1318 to schedule your free El Granada estimate, and you’ll see why homeowners from Half Moon Bay to Millbrae trust Barrett & Sons Construction with their biggest projects.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving El Granada and the San Mateo County coast since 1998.