Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
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AfterFast, Reliable Home Additions & ADU Across Bloomington
A home addition or ADU in Bloomington typically runs $45,000 to $130,000 for an addition and $90,000 to $220,000 for a new detached ADU, depending on square footage, foundation work, and how much of the original 1950s-70s framing and wiring has to be brought up to current San Bernardino County code. Barrett & Sons Construction has built room additions, garage conversions, and detached ADUs across the 92316 ZIP for years, and we know exactly what gets uncovered when walls open on these mid-century Bloomington homes. Call (877) 610-1318 any time and we’ll walk you through what your project will actually cost before you sign anything.
Why Barrett & Sons Construction Is Bloomington’s Preferred Home Additions & ADU Company
Tom Barrett founded this company in 1998, and the name on the truck is the same name that answers the phone. When you call us about an ADU or room addition in Bloomington, you are talking to a live person who knows construction, not an out-of-state call center. Tom’s sons run the crews, and Tom himself is on-site most days in Bloomington, Fontana, Rialto, and the surrounding unincorporated areas. We publish our name, address, and license number, so you can look us up before you put a deposit down.
Bloomington residents keep hiring us because we handle the thing that scares most homeowners: the written change order. When we open a wall on a 1960s Bloomington home and find cracked stucco, failed waterproofing, or undersized framing, you get a written scope change with a firm price before we touch anything else. The allowance that isn’t on paper is a surprise waiting for a date, and we won’t let that happen on our jobs. Every permit gets pulled, every inspection gets signed, and every job carries our 90-Day Done Right Promise in writing.
Our Home Additions & ADU Services in Bloomington
ADU Design & Permitting
Bloomington is unincorporated, which means every ADU permit is processed by San Bernardino County’s Building and Safety Division, not a local city hall. That changes timelines, inspection sequencing, and code interpretations. We handle the full County permitting path for Bloomington ADUs, from initial drawings through final sign-off, so your project doesn’t stall at rough-in because somebody assumed Rialto or Fontana rules applied. Home Additions & ADU work in this part of the county needs a contractor who knows where the field inspectors are coming from and how to schedule around them.
Garage Conversion ADU
Garage conversions in Bloomington run $30,000 to $80,000, and the single largest cost driver is what we find inside the existing structure. Many Bloomington garages from the 1950s-70s were built as simple car storage: no vapor barrier under the slab, minimal rebar, framing that was never engineered for living space. Converting one to a legal ADU means upgrading the foundation, insulating, running new electrical, and often replacing the original slab entirely. We write every one of those upgrades into the estimate before we start, so there is no sticker shock at week three.
New Detached ADU
A new detached ADU in Bloomington starts around $90,000 and can exceed $220,000 for a two-bedroom unit with a full kitchen. The soil under Bloomington is the wildcard. Expansive silty loam and clay heave dramatically between wet winters and 110°F summers, so we spec deeper continuous footings and pre-pour soil saturation as standard practice. Contractors coming from coastal LA counties frequently skip that step, and their slabs crack within the first year. We won’t.
Junior ADU & Interior Conversion
Junior ADUs and interior conversions work well on Bloomington’s oversized lots and in its mid-century floor plans. Converting an attached den, a finished basement, or a back section of a ranch home into a legal JADU is often the most cost-efficient route to rental income or multigenerational living. County code requires specific separation, egress, and kitchen limitations for a JADU, and we sequence the rough-in inspection early so an exposed wall doesn’t sit open for days waiting on a county inspector.
What happens when you call
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A real person answersNo phone trees - you reach a local pro.
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You get an upfront price rangeHonest numbers before anyone is dispatched.
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A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in Bloomington
We install materials you can look up, not mystery brands off a van. For Bloomington ADUs and room additions, we regularly work with Schluter systems for waterproofing in kitchens and baths, Grohe fixtures where the homeowner wants European build quality, and GAF roofing materials when an addition ties into a new roofline. If you have a specific brand in mind, tell us at the estimate and we’ll price it into the written scope. No surprises, no substitutions you didn’t approve.
Common Home Additions & ADU Problems We See in Bloomington Homes
- Slab heave from expansive clay: Bloomington’s silty loam and clay soils swell when wet and shrink when dry. A room addition or ADU built without deeper continuous footings and pre-pour soil saturation will show stepped cracks in the slab within the first two years. We treat this as standard practice on every Bloomington foundation, not an upgrade.
- Original stucco failing along beam pockets: Homes built from the late 1940s through the 1970s in Bloomington used post-and-beam or stick framing with stucco cladding. When we open a load-bearing wall for a room addition, we often find cracked stucco, loose beam pockets, and dry rot where rain entered over decades. That means a change order with a firm price, approved in writing, before we proceed.
- Failed waterproofing at old patio doors: On one 1960s post-and-beam home in the 92316 ZIP, our crew opened a wall for a room addition and found the subfloor swollen from a patio door that had leaked for years. We wrote a change order for new flashing, membrane, and subfloor replacement, coordinated the county inspection, and got the homeowner’s written approval before we poured anything. That is how it should work.
- Outdated wiring that can’t carry modern load: Mid-century Bloomington homes were built for 60-amp service and a few outlets per room. Add a kitchenette or laundry in an ADU, and the County will require a panel upgrade and new circuits. We find this on nearly every addition we start in the 92316 ZIP, and we budget for it in the written estimate rather than “discovering” it after demo.
Pricing for Home Additions & ADU in Bloomington, CA
Bloomington’s market for additions and ADUs falls into three broad bands. Here is the line-item range table we give homeowners at the first conversation, and these are the numbers we hold to unless the scope changes in writing:
| Project Type | Typical Bloomington Price Range |
|---|---|
| Home Addition (room addition, bump-out) | $45,000 - $130,000 |
| ADU Construction (new detached unit) | $90,000 - $220,000 |
| Garage Conversion ADU | $30,000 - $80,000 |
What actually drives a Bloomington addition into the high end of those ranges: foundation work on expansive soil, panel upgrades from 60-amp to 200-amp service, roof tie-ins that require replacing more of the original mid-century roof than expected, and any waterproofing remediation we find when walls open up. We give every Bloomington homeowner a free written estimate with these line items broken out, and we don’t change a number unless you sign a change order first. Call (877) 610-1318 to schedule yours.
We Also Serve Cities Near Bloomington
Beyond Bloomington proper, our crews handle home additions and ADUs in Fontana, Rialto, Glen Avon, and Pedley. If you are in one of those communities and need a room addition or ADU, the same owner-operated crew serves you. See our full Home Additions & ADU in Bloomington coverage for details on how we handle projects across the county line.
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 - Home Additions & ADU in Bloomington
Yes, San Bernardino County’s Building and Safety Division requires a permit for any attached garage conversion to an ADU in Bloomington, and the conversion triggers code upgrades the moment the County reviews your plans. The most common triggers: the original garage slab usually lacks a vapor barrier and has minimal reinforcement, so it must be replaced or over-poured; the existing 60-amp panel can’t carry an ADU load and must be upgraded; and the garage’s original roof framing often needs structural ties to meet current shear requirements. We sequence the rough-in inspection early so the county inspector sees the work before drywall closes it, which saves you from tearing out finished walls later. Call (877) 610-1318 for a free estimate on your garage conversion.
Bloomington’s silty loam and expansive clay heave and shrink significantly between wet winters and 110°F summers, so a new detached ADU needs deeper continuous footings, often with rebar schedules denser than standard plans show, plus pre-pour soil saturation to prevent settlement cracking. We also spec slab reinforcement beyond what a generic plan set calls for, because the first wet-dry cycle is where cheap foundations fail in this ZIP. Call (877) 610-1318 and we’ll explain exactly what our Bloomington foundation spec includes.
The biggest reason a Bloomington room addition quote changes after demo is water damage and structural decay hidden behind original stucco and under old patio doors: swollen subfloor, cracked beam pockets, dry rot, or soil movement that stressed the original frame. We handle this by pricing a written allowance for structural and waterproofing remediation into every Bloomington addition estimate, then documenting exactly what we found and what it costs in a change order you approve before we proceed. You never owe us a penny you didn’t sign for. Call (877) 610-1318 for an exact written estimate on your addition.
A permit protects you in ways that matter when you sell, refinance, or make an insurance claim, and in unincorporated Bloomington, the permit inspector works for you, not for the contractor. That’s why we like him. A permitted room addition means the County’s inspector verified the framing, electrical, and foundation meet current code, which protects your family while you live there and prevents a buyer’s inspector from flagging unpermitted work down the road. We pull permits and sign off inspections on every eligible Bloomington job. Call (877) 610-1318 to talk through what your project requires.
Santa Ana wind events and 110°F-plus summer heat in Bloomington shorten workable windows for concrete pours, exterior coatings, and roofing adhesives, which means we sequence the foundation, framing, and heavy exterior work for early mornings and cooler stretches. Intense UV also degrades low-grade roofing and siding materials far faster here than in coastal markets, which is why we spec GAF roofing and quality cladding that holds up to Bloomington’s sun. We plan your project’s timeline around Bloomington’s actual weather, not a generic California schedule. Call (877) 610-1318 for a free estimate and a realistic schedule.
Get Your Bloomington Home Addition or ADU Started Right
If you live in the 92316 ZIP and you’re thinking about a room addition, garage conversion, or new detached ADU, call Barrett & Sons Construction at (877) 610-1318 for a free written estimate. We’ll walk your Bloomington home with you, open up the questions that matter, and put every number on paper before work starts. Permits pulled, inspections signed, change orders in writing, and a 90-Day Done Right Promise on every job. Ask anyone on your street or look up the license number yourself.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving Bloomington and the Inland Empire since 1998.