







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 Colton
A room addition in Colton typically costs between $180 and $320 per square foot, with most projects landing between $54,000 and $96,000 for a 300-square-foot addition. The work usually takes 10 to 16 weeks from permit submittal to final inspection, depending on plan check turnaround and site conditions. If you’re weighing whether to add a bedroom, home office, or primary suite in Colton, the first step is a written scope and price, not a vague verbal estimate. Call (903) 568-7222 to schedule a free site visit and we’ll walk the lot with you, measure the actual setbacks, and put a real number on paper before anything gets signed.
Why Benson ADU Builders Is Colton’s Preferred Room Addition Contractor Company

Benson ADU Builders has built a reputation in Colton for doing what most contractors won’t: naming a price out loud and putting it in writing before the first shovel moves. Troy Eastman leads our Room Addition Contractor team with a simple rule: no homeowner in Colton should ever discover a $9,000 change order after the drywall is up. That’s why every project includes The Relay Visibility Guarantee, a written price before work starts, real-time progress tracking, and a 365-Day Done Right Promise. If the work isn’t right within a year, we make it right. No fine print, no arguing.
Our crews work regularly across Colton, from the neighborhoods along La Cadena Drive up to the hillside streets off Reche Canyon Road. Background-checked, uniformed technicians arrive on schedule, and a live person answers the phone around the clock. Colton homeowners have told us they chose Benson because we returned the call, showed up on time, and didn’t disappear between the estimate and the permit counter. That’s not a marketing line. It’s the bare minimum we’ve built the company around since 2006, part of the Relay Home Co. family.
Room Additions in Colton
Room Additions in Colton are one of the most practical ways to add square footage without moving, especially on lots where an ADU would eat too much yard or trigger extra permit layers. The first sentence of any honest bid should answer one question: will this addition fit inside the legal building envelope on your specific lot? In Colton, where housing stock spans mid-century ranches, 1970s track homes, and a few newer builds, the answer changes block to block. We do site measures, check the city’s setback requirements, and confirm the projected footprint before we quote a dollar figure. A standard 300-square-foot bedroom addition with a closet and no plumbing runs roughly $54,000 to $78,000 in Colton. Add a bathroom and you’re looking at $75,000 to $96,000 or more, depending on the slab work and sewer tie-in distance.
Bedroom Additions
A bedroom addition off an existing hallway or rear wall is the most straightforward room addition we build in Colton. The work includes foundation excavation, slab or raised-floor framing, wall framing, roof tie-in, insulation, drywall, electrical, flooring, and stucco or siding match. We pull the permits, schedule the inspections, and coordinate the plan check through the city. You see the progress photos as they happen, not at the end of week four.
Primary Suite Additions
A primary suite addition in Colton usually adds a bedroom, full bath, and walk-in closet to the rear or side of the house. That means plumbing rough-ins, a new sewer tie-in, and waterproofing, which pushes the cost toward the higher end of the range. The payoff is real living space that changes how the house works, not just another box with a window. We’ve built these on tight Colton lots by pushing the footprint toward the rear yard wherever the setback allows.
Modular Home Addition in Colton

Modular Home Addition projects in Colton take a different path than site-built framing: the wall panels, floor cassettes, and roof trusses are engineered and cut in a controlled facility, then assembled on your foundation. For Colton homeowners who want a tighter construction calendar, this can cut weeks off the framing phase and reduce weather delays. We’re authorized to build with leading prefab brands including Abodu, Cover, and Dvele, along with James Hardie cladding, which means you can research the exact panel system we’re proposing before you commit. A modular home addition in Colton generally runs $190 to $320 per square foot, with the final number tied to the brand, foundation requirements, and how much site work your lot needs.
Prefab Panel Framing
Prefab panel framing arrives on a truck in marked sections, and the assembly on site takes days instead of weeks. For Colton’s older neighborhoods with narrow side yards, the smaller staging footprint is a real advantage. Panels get craned or carried in, set on the foundation, and tied to the existing structure with steel connectors. The engineering documents are stamped and submitted with the permit package.
James Hardie Siding Match
Matching an addition to an existing stucco home takes a careful hand, and on Colton’s mid-century houses the old finish has often faded or been patched over the years. James Hardie fiber cement siding gives us a clean, durable option when stucco matching isn’t practical. It holds paint well, survives Colton’s summer heat without warping, and comes in enough profiles to blend with the original architecture. We stock the common profiles locally and can color-match on site.
Trusted Brands We Service in Colton
Colton homeowners should know exactly what materials are going into their addition, and that means naming brands you can look up. We build with Abodu and Dvele prefab systems, install James Hardie siding, and can source Cover panels for tight-lot builds. These aren’t generic off-brands; they’re companies with published specs, engineering docs, and warranties. For Colton jobs specifically, we keep common finishing materials and panel components in regional inventory, which means less waiting on a truck from out of state when a piece arrives damaged or short. You get a real brand name on the proposal, not a vague “quality materials” line.
Common Room Addition Contractor Problems We See in Colton Homes
- Old lots with nonconforming setbacks. Colton’s older housing stock sits on lots platted before modern side-yard setbacks were standardized. A 300-square-foot addition can be layout-feasible on one street and need a variance two blocks away, because the legal buildable width is narrower than the homeowner assumes from looking at the yard.
- Bidding from a sketch instead of a survey. We’ve seen contractors price a Colton addition off a hand-drawn floor plan, then discover the actual property line is three feet closer than anyone thought. The price shifts after the survey comes back. We don’t quote a final number until we’ve verified the lot.
- Assuming it’s an over-the-counter remodel. A new foundation, framing, and roof tie-in is not a simple remodel permit in Colton. It needs plan check and multiple inspections, which adds time to the calendar. Anyone claiming a room addition can be permitted as a quick over-the-counter job is setting you up for a stop-work order.
- Underestimating the tie-in work. Matching existing stucco, roofline, and floor elevation on Colton’s older homes is often the single biggest hidden line item. Skip a full site measure and the final number drifts. We include the tie-in scope in the written price from the first conversation.
Pricing for Room Addition Contractor in Colton, CA
A room addition in Colton runs $180 to $320 per square foot. A basic 200-square-foot bedroom without plumbing starts around $36,000. A 300-square-foot addition with a full bath lands between $75,000 and $96,000. What moves the number after work starts: variances if the lot is over the setback line, extra sewer line distance to the main, and stucco or roofline matching on older homes. That’s exactly why we don’t hand you a verbal ballpark and disappear. The written price names the scope, the brands, the permit path, and the tie-in work. Call (903) 568-7222 for a free estimate, and you’ll get a number you can actually plan around.
We Also Serve Cities Near Colton
Our crews work throughout the Inland Empire corridor, including Colton and the neighboring communities of Grand Terrace, Loma Linda, Riverside, and San Bernardino. If you’re just over the Colton line and weighing a room addition, the same written pricing and 365-Day Done Right Promise applies. Call us and we’ll schedule a site visit wherever you are in the area.
Serving Colton, CA - Our Local Coverage Area
We’re based in the Colton 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 Colton
A room addition in Colton with new foundation, framing, and roof tie-in needs a full plan check with the city’s building department, not an over-the-counter remodel permit. The drawings, structural calculations, and energy compliance docs get submitted together, and the review typically takes two to six weeks depending on current city workload. Call (903) 568-7222 and we’ll explain the exact path for your project, including what the city will ask for and when inspections land.
Colton’s older lots were often platted before modern side-yard setbacks were standardized, so the legal buildable area can be narrower than the yard looks. That means your addition footprint may need to shift toward the rear of the lot or shrink in width to avoid a variance. We verify the actual setbacks and lot lines during the site measure before quoting a price, so you’re not paying for a redesign later.
The biggest cost drivers once a Colton room addition gets underway are foundation conditions, sewer tie-in distance, and matching existing stucco or roofline on an older home. A lot with expansive soil or a sewer line twenty feet from the addition will cost more than the same square footage on a clean lot. Our written price includes those scope items from the first conversation, so change orders are the exception, not the rule. Call (903) 568-7222 for an exact quote based on your house and lot.
In Colton, a modular home addition can be cheaper than stick-built when the lot access is tight or the framing window is short, with typical prices from $190 to $320 per square foot. The savings come from faster assembly and less on-site labor, but the foundation and tie-in work still cost the same. We’ll give you parallel numbers for prefab and site-built so you can decide on real math, not a sales pitch.
A typical room addition in Colton takes 10 to 16 weeks from permit submittal to final inspection. Plan check runs two to six weeks, foundation and framing take three to five weeks, and finishes, inspections, and punch list add another four to six. We track the whole thing with real-time updates and photos, so you know exactly where the project stands every week.
Written by Troy Eastman, Owner at Benson ADU Builders, serving Colton and the surrounding Inland Empire communities.


