Fast, Reliable Home Addition Contractor Across Bloomington
Home additions in Bloomington cost between $180 and $420 per square foot, with a typical 400-square-foot room addition running $72,000 to $168,000. The price moves most on what’s hiding inside walls built between the 1950s and 1980s: cloth-wrapped wiring, 60-amp panels, and slabs that have shifted under old carport pads. We’re Home Addition Contractor specialists who plan for those discoveries before demolition starts, not after. Call (707) 383-5338 to schedule a walkthrough and get a written price before any work begins.

Why Seedling ADU Builders Is Bloomington’s Preferred Home Addition Contractor Company
We know that Bloomington runs on county timelines, not city ones. When a homeowner calls us from a wide lot off Cedar Avenue or a ranch home near Bloomington Avenue, we already understand that their permit goes to San Bernardino County Land Use Services, not a local counter. That’s the first place most addition projects stall, and we plan for it from day one instead of discovering it mid-project.
Our crews show up in uniform, background-checked, and with shoe covers and drop cloths before they cross your threshold. Families with kids and pets don’t have to wonder who’s walking through the door, and they don’t have to clean construction dust off their floors at night. Before the crew leaves each day, we photograph the clean-up so you can see exactly what we left behind.
Ben Ortega, who leads our work across Bloomington, insists on one thing before any tool is picked up: a written price. Not a ballpark, not a handshake. A line-item written price that includes pre-inspection allowances for the wiring and slab surprises this era of Bloomington housing tends to hide.
Every project is backed by the 365-Day Done Right Promise in writing. If it’s not done right, we make it right. That’s the whole promise, no fine print.
Sunroom Addition in Bloomington
A sunroom addition in Bloomington runs $45,000 to $110,000 depending on square footage, glazing, and whether the room ties into your existing HVAC or needs a dedicated mini-split. Homeowners on the wide lots south of the 10 freeway and along Cedar Avenue often choose sunrooms as a way to add square footage without the full structural work of a second story.
Cooling and Glazing Choices
Bloomington summers regularly hit 105 – 110°F, so a sunroom with single-pane glass becomes a greenhouse by noon. We size glazing packages and mini-split line sets for that heat, not for a coastal climate. Low-E glass and proper shading are standard recommendations here, not upgrades.
Slab and Foundation Reality
Many Bloomington sunrooms sit on slabs poured decades ago for patios or carports. Those slabs often weren’t engineered for enclosed living space. We inspect before we quote, and if the slab needs repair or a structural upgrade, that number is in your written price from the start, not a surprise added after the demo crew leaves.
Room Addition Contractor in Bloomington
A room addition contractor in Bloomington handles everything from a 200-square-foot bedroom bump-out to a 600-square-foot family room with a half bath, and our projects typically run $180 to $420 per square foot. The final number depends on what we find when we open the walls: older Bloomington ranch homes frequently have cloth-wrapped wiring, 60-amp panels, and framing that predates current seismic and shear codes.
Pre-Demolition Inspection and Written Allowances
We don’t quote a Bloomington room addition assuming the walls are empty. We include written allowances for electrical panel upgrades, wiring replacement, and slab repair in your contract before demo starts. If we open the wall and find exactly what we expected, those allowances shrink. If we find worse, we document it with photos and bring you a written change order to sign before work resumes.

Working Around Family Life
Room additions next to bedrooms or during school hours don’t need to be chaos. We stage work so noisy cutting happens in defined blocks, we keep hallways clear, and we use pet-safe products where there’s a choice. Your kids keep their sleep schedule and your dog keeps their routine.
Trusted Brands We Service in Bloomington
We work hands-on with Abodu, Cover, and Mighty Buildings systems, plus James Hardie siding and trim materials sourced for Bloomington’s summer heat and sun exposure. Because we plan around San Bernardino County’s ADU pre-approved plan program where it applies, Bloomington homeowners get access to these brands without the weeks-long design delays that can stall a project. As experienced ADU Builders in Bloomington, we know how to keep these projects moving. We maintain local supplier relationships across the Inland Empire so materials aren’t waiting on a truck from out of state while your county inspection date passes.
Common Home Addition Contractor Problems We See in Bloomington Homes
- Cloth-wrapped wiring and undersized panels. Homes built between the 1950s and 1980s in Bloomington often have original 60-amp panels. Opening a wall for an addition triggers a county code review that will require an upgrade, and if you didn’t budget for it, the job stalls mid-demo.
- Heaved or cracked slabs under old carport pads. Many Bloomington lots kept their original carport or patio slabs. Those slabs often weren’t poured for enclosed living space and need repair or replacement before framing can start.
- Cooling that can’t keep up with 110°F afternoons. A minimally insulated room addition or converted garage becomes unlivable during San Bernardino Valley heatwaves. Undersized mini-splits leave a room that never passes a habitability walkthrough in summer.
- Permits filed with the wrong department. Bloomington is unincorporated, so addition permits go to San Bernardino County Land Use Services, not a city counter. Filing with the wrong agency stalls the project before plan check even starts.
Pricing for Home Addition Contractor in Bloomington, CA
In Bloomington, a standard room addition runs $180 to $420 per square foot, which puts a 400-square-foot addition between $72,000 and $168,000. Sunroom additions typically fall between $45,000 and $110,000, while second story additions on existing ranch footprints start around $250 per square foot and climb based on structural reinforcement needs. The biggest cost variables in this market are electrical panel upgrades ($3,500 to $6,500), slab repair ($1,800 to $9,000 depending on extent), and HVAC sizing. You’ll get a written price before any work starts, with allowances for these discoveries already factored in. Call (707) 383-5338 to schedule a free estimate and walkthrough.
We Also Serve Cities Near Bloomington
While we focus on Bloomington’s unincorporated permit path and wide quarter-acre lots, our crews regularly work in nearby Rialto, Fontana, Riverside, and Grand Terrace. If you’re searching in those areas, our Home Addition Contractor in Bloomington team can tell you whether a county or city permit applies to your address and what that means for your timeline.
Serving Bloomington, CA - Our Local Coverage Area
We’re based in the Bloomington 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 Home Addition Contractor in Bloomington
San Bernardino County Land Use Services issues addition permits for Bloomington because the community is unincorporated. There’s no local city building counter. Plan-check and inspections run on county timelines, and homeowners who don’t pre-schedule county inspections can lose weeks before a single wall is opened. Call (707) 383-5338 and we’ll walk you through the county’s process for your specific permit.
Homes built here between the 1950s and 1980s often have cloth-wrapped wiring, 60-amp electrical panels, and slab foundations that have shifted over decades. Opening a wall to tie in an addition triggers a county code review that requires upgrades to current standards. We include written allowances for these discoveries in your contract, and any change gets documented and approved by you in writing before work continues.
Yes, and many Bloomington lots are ideal for it. The wide, rectangular parcels left from the area’s agricultural era often still have detached garages or carport structures. The catch is slab condition and panel capacity, which frequently need upgrades to meet San Bernardino County code. A garage conversion can save $30,000 to $60,000 compared to new construction, but only if the existing structure passes inspection. We assess that before you commit to a path.
Yes. Bloomington regularly hits 105 – 110°F in summer, and a minimally insulated addition becomes unlivable without properly sized mini-split HVAC or a tie-in capable of handling the extra load. We size cooling for the San Bernardino Valley’s actual heat, not a generic climate average. That’s the difference between a room you use in July and a room you abandon by noon.
Pre-schedule county inspections as soon as your permit number is assigned, and use the county’s ADU pre-approved plan program where your project qualifies. Homeowners who coordinate inspection timing up front avoid the weeks-long gaps that stall most Bloomington additions. We handle this scheduling as part of our written project plan. Call (707) 383-5338 for a free estimate and a timeline that reflects actual county scheduling.
Written by Ben Ortega, Owner at Seedling ADU Builders, serving Bloomington and the surrounding Inland Empire.