A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateFast, Reliable Room Addition Contractor Across Stevenson Ranch
A room addition in Stevenson Ranch typically runs $180 – $320 per square foot for site-built construction, with most projects landing between $85,000 and $220,000 depending on size, foundation work, and whether you’re on septic or sewer. We’re Benson ADU Builders, and we handle the part most contractors gloss over: the county permitting, the septic setbacks, the grading, and the long driveway pours that define building here. Call (903) 568-7222 for a written price before any work starts.
Stevenson Ranch is unincorporated LA County. That one fact changes everything about how a room addition gets permitted, engineered, and priced. Our crews work off Pico Canyon Road, up Stevenson Ranch Parkway, and across the acreage parcels near the 5, so we know what county plan check actually costs in time and money. If you’ve been quoted by a Santa Clarita city-limits contractor, you’ve probably been quoted wrong.
Why Benson ADU Builders Is Stevenson Ranch’s Preferred Room Addition Contractor Company
Most Stevenson Ranch homeowners call us after a city contractor fumbles the county submittal. We pull permits through LA County Public Works Building & Safety, not the City of Santa Clarita, and we build the fire review and septic review into the timeline from day one. That’s not a sales pitch – it’s the difference between a permit that clears in weeks and one that sits for months. Troy Eastman leads our estimating team, and he signs off on every Stevenson Ranch scope personally.
We put a written price in your hands before a single shovel turns. No verbal estimate that drifts upward after demo. The 365-Day Done Right Promise covers the work for a full year: if it’s not right, we make it right, in writing, stamped on your project file. Homeowners from the neighborhoods off Poe Parkway to the cul-de-sacs near The Oaks Club tell us the same thing: they knew exactly who was walking onto their property because our technicians arrive background-checked and in uniform, and a live person answers the phone when they call.
You can research the brands we build with – Abodu, Cover, Dvele, James Hardie – and verify their reputations yourself. That’s the point. We don’t ask you to trust us on blind faith. We hand you names you can look up and a Room Addition Contractor team that stands behind the full scope, from pad to paint.
Home Addition Plans in Stevenson Ranch
Home Addition Plans in Stevenson Ranch start with a survey and a septic or sewer verification, because the answer changes where your addition can sit by up to 15 feet. We draw plans that account for county setback rules, fire department access requirements, and the drainage patterns on your specific lot. A full plan set for a 400 – 600 sq ft addition in Stevenson Ranch typically runs $4,500 – $9,000, including engineering and county submittal coordination.
Setback and Leach Field Reality
On a sewer-connected parcel near Stevenson Ranch Parkway, your addition can usually sit where you want it within standard rear and side setbacks. On septic, LA County requires separation between any new structure and the leach field. We’ve seen half-acre lots off Pico Canyon Road where that one rule forced the addition 12 feet sideways and added $8,000 in engineering and grading. We confirm it before we quote, not after demo starts.
Grading and Drainage Plans
Stevenson Ranch’s open, sloped lots shed water fast during Santa Clarita Valley winter storms. A room addition without a site-specific drainage plan invites foundation undermining and flooded pads. We include grading and swale design in every Home Addition Plans package because skipping it on these lots costs more later.
In Law Suite Builders in Stevenson Ranch
In Law Suite Builders in Stevenson Ranch operate on one simple rule: the septic system and the driveway dictate the budget. A detached 600 sq ft in-law suite on a sewer parcel with street access typically runs $160,000 – $230,000. The same suite on a septic parcel with a long unpaved driveway off a county road can hit $240,000 – $310,000. We scope both scenarios before quoting so the number doesn’t move later.
Detached Suites on Acreage
Detached in-law suites are the fastest-growing request we field in Stevenson Ranch. Families are housing parents, adult children, or rental tenants without sacrificing the main house. Our crew built a detached 600 sq ft in-law suite on a half-acre lot off Pico Canyon Road where the existing septic system forced the structure 12 feet further from the leach field than the homeowner expected. We pulled the permit through LA County Building & Safety, set the pad with a deeper grade beam to handle expansive soils, and pumped the concrete pour from the street because our truck couldn’t navigate the unpaved driveway. James Hardie siding matched the main house, and it passed county inspection first time.
Attached Additions with Separate Entrances
If your lot can’t accommodate a detached structure, an attached in-law suite with a private entrance and kitchenette is often the right move. These run $140,000 – $200,000 in Stevenson Ranch depending on whether you’re tying into existing plumbing or running new lines across the lot. The septic question still applies: an added bathroom changes your leach field load, and the county wants to see the calculation.
Trusted Brands We Service in Stevenson Ranch
We’re authorized to build with Abodu, Cover, Dvele, and other leading prefab manufacturers, and we keep a steady pipeline of James Hardie cladding moving to Stevenson Ranch job sites. Why prefab? Factory-built panels arrive with tighter tolerances than stick framing and cut weeks off a county-permitted addition. When you call about a room addition or in-law suite, we’ll walk you through prefab versus site-built pricing with the brand names attached so you can research them yourself. We don’t lock Stevenson Ranch customers into one product. You get curated options and a written price for each.
Common Room Addition Contractor Problems We See in Stevenson Ranch Homes
- Quoting before checking septic or sewer. A contractor quotes a room addition assuming city sewer, then discovers leach field setbacks that add 10 – 15 feet of relocation and thousands in engineering. We verify the parcel first. Always.
- Assuming a City of Santa Clarita permit timeline. LA County plan check, fire review, and septic review run on a different schedule with different submittal packages. Out-of-area contractors miss this and your permit sits. We run county permitting every week.
- Underestimating grading on open, sloped lots. Stevenson Ranch’s graded parcels look simple until winter runoff pools against a new foundation. Without a drainage plan, you’re risking structural damage. We include grading and swale design in every scope.
- Long unpaved driveways and equipment access. Concrete trucks and material deliveries can’t always reach the pad. We plan for pump pours and staged delivery before the quote, so your price doesn’t jump when the truck can’t make the turn.
Pricing for Room Addition Contractor in Stevenson Ranch, CA
Here’s what Stevenson Ranch homeowners should expect. Site-built room additions run $180 – $320 per square foot. A 400 sq ft bedroom addition: $72,000 – $128,000. A 600 sq ft attached in-law suite: $140,000 – $200,000. A 600 sq ft detached in-law suite: $160,000 – $310,000 depending on septic, driveway access, and grading. Prefab options from Abodu, Cover, or Dvele can shift both cost and timeline, so we price both paths. Every estimate includes a written line-item breakdown. Call (903) 568-7222 for your free estimate.
We Also Serve Cities Near Stevenson Ranch
Our crews cover Stevenson Ranch and the surrounding Santa Clarita Valley, including Stevenson Ranch, Newhall, Valencia, Santa Clarita, and Castaic. If you’re in one of those communities and need a room addition, in-law suite, or detached ADU, the same written-price guarantee applies.
Serving Stevenson Ranch, CA - Our Local Coverage Area
We’re based in the Stevenson Ranch 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 Room Addition Contractor in Stevenson Ranch
You need a county permit. Stevenson Ranch is unincorporated Los Angeles County, so room additions over single-family zoning thresholds go through LA County Public Works Building & Safety, not the City of Santa Clarita. County plan check includes separate fire review and, on septic parcels, a septic review that city contractors often don’t account for. Call (903) 568-7222 and we’ll confirm your permitting path before you commit.
Yes. LA County requires separation between any new structure and your leach field, and on Stevenson Ranch acreage that setback can push your addition 10 – 15 feet further than you planned. That changes grading, foundation design, and cost. We verify your septic or sewer status before we quote, so the number you get is the number you pay. Call (903) 568-7222 for a free estimate.
A long unpaved driveway can add $3,000 – $8,000 to a Stevenson Ranch room addition. Concrete trucks may not be able to reach the pad, which means pump pours from the street. Material delivery gets staged in phases. We scope this before quoting. Call (903) 568-7222 and we’ll walk your specific driveway access.
Yes, and it’s one of the most underestimated costs on Stevenson Ranch lots. A graded but undrained lot sheds Santa Clarita Valley winter runoff straight toward your new foundation. We include a drainage plan and swale design in every scope. Skip it and you’ll pay for fixes within a year. Call (903) 568-7222 for a written estimate.
Yes, and combining them usually saves money. One permit package, one grading and drainage plan, one mobilization. We regularly scope a room addition plus a detached ADU or shop on Stevenson Ranch acreage parcels, and the combined price beats doing them separately. Call (903) 568-7222 and we’ll price the full scope.
Ready to get a written price? Call (903) 568-7222 now. We’ll answer live, walk through your Stevenson Ranch parcel’s septic, grading, and access realities, and put a number in writing before any work starts.
Written by Troy Eastman, Owner at Benson ADU Builders, serving Stevenson Ranch and the surrounding Santa Clarita Valley.
