Home Additions & ADU in Bloomington - Plans, Permits & Build, One Fixed Price

Fast, Reliable Home Additions & ADU Across Bloomington

A home addition or ADU in Bloomington typically runs $45,000-$130,000 for room additions and $90,000-$220,000 for detached units, with permits routed through San Bernardino County’s Land Use Services Division rather than a city building department. We’re familiar with the county’s inspection scheduling and the 1950s-1970s housing stock that dominates neighborhoods here, so we build those realities into every written quote before work starts. Call (909) 373-9612 to schedule your free estimate.

Call (909) 373-9612

Why Rowan Construction Group Rancho Cucamonga Is Bloomington’s Preferred Home Additions & ADU Company

We’ve delivered written-price projects across the Inland Empire since 2007, and our Home Additions & ADU team has particular experience with the unincorporated county permitting that governs Bloomington. Where Rialto and Fontana homeowners deal with city building departments, Bloomington’s permits, inspections, and code enforcement all flow through a single San Bernardino County regional office. That operational difference matters. We account for it in our scheduling, our draw schedules, and our contract language.

Our crews are background-checked and uniformed, and a live person answers calls 24/7. Every visit produces a documented photo record, included as standard. Under Clause 1 of the Haven Standard, the price is written before anyone picks up a tool. Under the 365-Day Done Right Promise, if it’s not done right, we make it right. We’ve kept projects within a few percent of the agreed price across 4,000-plus jobs by requiring a signed change order before any additional work proceeds.

Dispatch and scheduling are coordinated from our Inland Empire office, with crews serving Bloomington locally. We know the difference between a 1958 slab-on-grade ranch near Valley Boulevard and a 1972 wood-frame near Slover Avenue, and we know what opening those walls typically reveals.

Our Home Additions & ADU Services in Bloomington

ADU Design & Permitting

Every Bloomington ADU starts with a site evaluation and a permit strategy mapped to San Bernardino County’s Land Use Services Division. Because county inspectors cover a sprawling multi-community territory from one regional office, inspection windows routinely stretch days longer than in incorporated cities. We build that lag into our project schedule from day one. A typical detached ADU in Bloomington runs $90,000-$220,000, and the permit package includes title 24 energy calculations, structural plans, and utility connection diagrams. We don’t start construction until the permit is in hand and the written price is signed.

Garage Conversion ADU

Converting a garage in Bloomington costs $30,000-$80,000 and triggers the same county permit path as a new detached unit. Most Bloomington garages share a slab with the main house, built in the same 1950s-1970s era, which means the concrete may need moisture remediation and the electrical panel often needs upgrading from 100 amps to 200 amps to handle the added circuits. We inspect the slab, the framing, and the panel before we write the price, so these aren’t surprises. The Haven Standard requires it.

New Detached ADU

A new detached ADU on a Bloomington lot means navigating setback requirements, utility trenching, and the county’s inspection sequence. Summer temperatures exceeding 105°F force accelerated concrete finishing schedules and admixtures to control cure rates. We pour foundations in morning windows and schedule masonry and roofing outside peak afternoon heat. The written quote includes these sequencing assumptions, and any weather delay is documented with a photo record and a revised schedule, not a verbal promise.

Junior ADU & Interior Conversion

Junior ADUs in Bloomington, typically carved from existing interior space or attached to the main structure, still require county permits and must meet fire separation and egress requirements. In the older housing stock here, we regularly find that the existing HVAC system was never sized for additional conditioned square footage. We test capacity during our initial inspection and write the mechanical upgrade into the original contract if needed, not as a mid-project change order.

Room Additions

A room addition on a Bloomington home, typically $45,000-$130,000, almost always involves tying into existing slab-on-grade construction and wood-frame walls that may contain lead paint or asbestos insulation. We recently finished a 400 sq ft room addition off an original 1962 wood-frame, slab-on-grade ranch in Bloomington, and once we pulled the permits and opened the exterior wall, the existing framing failed a load-bearing check, the 100-amp panel couldn’t carry the added circuits, and the old slab waterproofing under the adjacent patio had failed. We handled it with a written change order and a revised draw schedule before touching anything: licensed remediation of the lead paint, a panel upgrade, sistered framing, and fresh waterproofing - all priced, approved in writing, and folded into the county inspection sign-off. The client never saw a surprise number because every allowance was set in the contract up front.

ADU Site Prep & Utilities

Site prep in Bloomington means trenching for sewer and water connections, often across clay-heavy Inland Empire soil that shifts with seasonal moisture changes. We call for geotechnical review when grading exceeds county thresholds, and we document substrate conditions with photos before any concrete goes in. The utility connection cost is line-itemed in the written quote, not buried in a contingency percentage.

Second Story Additions

Adding a second story to a Bloomington slab-on-grade home requires structural verification that the original foundation and framing can handle the load. Many 1960s-era homes here were built with perimeter footings adequate for single-story construction only. We bring in a structural engineer for a load-path analysis before we write the price, and that engineering cost is disclosed upfront.

Sunrooms & Enclosed Patios

Enclosing a patio in Bloomington means dealing with the same failed waterproofing we see on adjacent slabs, plus Title 24 energy compliance for conditioned space. We inspect the existing slab for moisture intrusion, specify the glazing package by U-factor and SHGC, and pull the county permit for electrical and structural. The written quote names the window manufacturer and the insulation R-value, not “windows and insulation.”

Before

After

Trusted Brands We Service in Bloomington

Our quotes draw from fifty-plus vetted brands, and we name the ones we’re specifying. For ADU kitchens, we quote KraftMaid or Wellborn cabinets with Silestone or Caesarstone countertops, not “stone tops” or “cabinet grade.” Bathroom fixtures are Kohler or Moen, with model numbers you can look up. GAF or Owens Corning roofing, Belgard or Techo-Bloc pavers if your ADU includes hardscape. We stock these lines through Inland Empire distributors, so material lead times don’t drive your schedule. The brand name, the spec, and the price are all in writing before work starts.

Common Home Additions & ADU Problems We See in Bloomington Homes

• Contractors not accounting for county inspection lag. San Bernardino County’s single regional office covers multiple unincorporated communities, so inspection appointments run days longer than in Fontana or Rialto. Contractors who don’t build this into their schedule put crews on standby at full labor cost, then rush concrete pours during 105°F+ afternoon heat to make up time. The cure cracks. We schedule around the lag and pour in morning windows.
• Undersized electrical panels in 1950s-1970s homes. Opening walls on Bloomington’s slab-on-grade housing stock regularly reveals 100-amp panels that can’t handle added circuits, plus lead paint or asbestos insulation that triggers mandatory remediation once a permit is filed. We inspect for these conditions before quoting and write allowances into the contract, so the price moves only if you approve a change order.
• Failed slab waterproofing on adjacent patios and foundations. The original waterproofing membrane under many Bloomington slabs has degraded after sixty-plus years of Inland Empire heat cycling. We test for moisture intrusion during our initial site evaluation and specify remediation in the written scope if needed, not as a discovery-day surprise.
• Skipping inspection-first sequencing. Rough-in electrical, plumbing, and structural framing must pass county inspection before drywall closes them up. Contractors who rush past this step to meet an unrealistic schedule face failed sign-off and expensive rework. We build the county’s inspection timeline into every draw schedule, and we don’t close walls until the inspector signs off.

Pricing for Home Additions & ADU in Bloomington, CA

We Also Serve Cities Near Bloomington

Our crews work throughout the Inland Empire, including Bloomington and neighboring Rialto, Fontana, Mira Loma, and Rancho Cucamonga. Each city has its own permitting environment - city building departments in Rialto and Fontana, county jurisdiction here in Bloomington - and we quote accordingly.

FAQs - Home Additions & ADU in Bloomington