Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Before
After
Before
AfterFast, Reliable Home Additions & ADU Across Maywood
A typical home addition or ADU in Maywood runs $45,000-$130,000, with detached ADUs reaching $90,000-$220,000 and garage conversions landing at $30,000-$80,000 depending on scope, age of the existing structure, and what the LA County permit process requires for pre-1950s housing stock. We’re Rowan Construction Group, and our crews work Maywood’s 1.18 square miles regularly - dispatch and scheduling run from our Los Angeles office, but the trucks that show up know these lots, these foundations, and these permit cycles. Call (562) 203-4508 to schedule your free estimate.
Why Rowan Construction Group Pasadena Is Maywood’s Preferred Home Additions & ADU Company
We’ve delivered 4,000-plus projects since 2007, every one with a written price before work started and a documented photo record when the crew left. In Maywood specifically, that discipline matters more than most places - there’s no vacant land, no staging yard, and no margin for a contractor who improvises.
Our Home Additions & ADU team has walked enough 1920s bungalows in Maywood to know which foundations are original unreinforced concrete, which walls will test positive for lead paint once opened, and how to sequence a garage conversion so the household isn’t displaced for a month. Reviews from Maywood customers consistently cite the flat written quote and the signed change order process - the administrative discipline Haven acquired Rowan for, and the reason projects finish within a few percent of the agreed cost.
Response time to Maywood is same-day for initial consultations, with crews already routing through the 90270 zip and adjacent Bell Gardens, Pico Rivera, Alhambra, and El Monte. A live person answers calls 24/7, and every technician is background-checked and uniformed before arriving.
Our Home Additions & ADU Services in Maywood
Garage Conversion ADU
Garage conversions are the most common ADU type we build in Maywood, and for good reason - most properties have a detached or attached garage from the 1940s-1960s, and converting it avoids the foundation and utility trenching costs of a new detached unit. The catch is the slab: Maywood’s older garages often sit on 4-inch unreinforced concrete with no vapor barrier, and the high impervious-surface coverage here means groundwater pushes up through that slab as efflorescence and spalling. We test the slab before quoting, because a conversion that needs a new foundation is a different job than one that doesn’t. Typical garage conversion in Maywood: $30,000-$80,000.
New Detached ADU
A new detached ADU on a Maywood lot means building to the property lines - literally. With structures often inches from neighbors and no side yard to speak of, we crane-set prefab wall panels or build in tight sequential phases to minimize disturbance. The LA River channel proximity means drainage design is non-negotiable; we specify sealed joints and elevated footings to keep slab moisture out. And if your lot borders Vernon, we test soil before excavation - diesel-tinged ground near that industrial boundary triggers DTSC review that can add weeks to permitting. We’ve handled it. Typical detached ADU in Maywood: $90,000-$220,000.
Room Additions
Room additions on Maywood’s 1920s-1950s bungalows almost always require seismic retrofitting to tie the new structure to the old, plus lead and asbestos abatement once walls open. LA County doesn’t grandfather these; the testing is mandatory and the abatement is line-itemed in our written quote from day one, not sprung as a surprise change order. We also match rooflines and siding profiles that haven’t been manufactured in seventy years - sourcing reclaimed materials or custom-milled replacements is standard on these jobs, not a specialty upsell. Typical room addition in Maywood: $45,000-$130,000.
Junior ADU & Interior Conversion
Junior ADUs - conversions within the existing footprint, with a separate entrance - work on Maywood’s smaller lots where a detached unit won’t fit the setback requirements. We often carve these from underutilized rear bedrooms or enclosed porches, running new electrical and plumbing while keeping the primary residence fully occupied. The challenge is the 1920s-era electrical panel, which typically needs upgrading from 60-amp service to 200-amp to handle the additional load. We identify this in the initial walkthrough and price it into the written scope.
What happens when you call
- 1
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.
Before
AfterTrusted Brands We Service in Maywood
Our quotes draw from fifty-plus vetted brands, and we stock local inventory for Maywood jobs to avoid the delays that kill tight-lot schedules. For fixtures on ADU kitchens and baths, we specify Grohe and Sterling for their corrosion-resistant finishes - the industrial-adjacent air here accelerates pitting on lesser hardware. On roofing tied to additions, we use GAF and CertainTeed shingles with stainless or hot-dip fasteners, not electro-galvanized, because the salt-laden inland coastal air plus Vernon-area fallout eats standard hardware within five years. The price gap between coastal-spec and inland-spec hardware is real - typically $800-$2,400 on a full addition - but the cheap spec costs more when you’re replacing railings and re-flashing before the mortgage is paid.
Common Home Additions & ADU Problems We See in Maywood Homes
- Corrosion from salt air and industrial fallout. Standard galvanized fasteners, untreated steel railings, and plain fence posts fail early in Maywood’s microclimate. We specify hot-dip galvanized or stainless hardware and sealed paver joints as baseline, not upgrades.
- Cramped lots with zero staging space. Material delivery has to be timed to the hour; drywall and framing left on the street get soaked by ground moisture or cited by code enforcement. We coordinate just-in-time delivery and neighbor notifications as standard project management.
- Pre-1950s hazardous materials in every wall. LA County requires lead and asbestos testing before demo on any pre-1978 structure, and Maywood’s housing stock is overwhelmingly pre-1950. We build testing and potential abatement into the original written quote - no mid-project surprises.
- Poor drainage toward the LA River channel. Fully built-out Maywood has near-total impervious surface coverage. Foundation moisture, cracked slabs, and efflorescence are routine. We specify elevated footings, perimeter drains, and vapor barriers on any addition touching existing foundations.
Pricing for Home Additions & ADU in Maywood, CA
These are the ranges we write on Maywood quotes before any work starts. Every number is flat-priced with a written scope and warranty, not an estimate that drifts.
| Service | Typical Range in Maywood |
|---|---|
| ADU Construction (new detached) | $90,000-$220,000 |
| Garage Conversion ADU | $30,000-$80,000 |
| Home Addition (room or second story) | $45,000-$130,000 |
| Window Replacement (addition tie-in) | $4,500-$15,000 |
| Roof Replacement (addition match) | $8,000-$20,000 |
| Paver Patio (ADU outdoor space) | $3,500-$11,000 |
What moves the number: age of existing structure (pre-1950s triggers hazardous-material testing), foundation condition, soil contamination near the Vernon border, seismic retrofit requirements, and whether the electrical service needs upgrading. We deliver the written price after a site visit, not a phone guess. Bring a competitor’s written estimate and we’ll review it line by line at no charge - our Free Second Opinion, standing offer since 2007.
We Also Serve Cities Near Maywood
Our crews route regularly through Bell Gardens, Pico Rivera, Alhambra, and El Monte - the same tight-lot, pre-war housing stock, the same LA County permit requirements, the same need for a contractor who writes the price before picking up a tool. If you’re searching for Home Additions & ADU in Maywood or any of these neighboring cities, the same flat-quote discipline and 365-Day Done Right Promise apply.
Serving Maywood, CA - Our Local Coverage Area
We’re based in the Maywood 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 Maywood
Yes, if the structure was built before 1978 - and in Maywood, that is nearly every home. LA County requires certified testing before walls open, and abatement if levels exceed thresholds. We build the testing cost into your written quote from the first walkthrough, not as a mid-project change order. Call (562) 203-4508 for an exact quote - estimates are free.
Standard galvanized hardware corrodes within 3-5 years here. Maywood’s inland coastal air carries enough salt to pit electro-galvanized fasteners, and industrial fallout from the adjacent Vernon boundary accelerates the process. We learned this on a 1920s bungalow near the Vernon edge - the client’s initial allowances priced plain steel posts and galvanized fence hardware; we wrote a change order for hot-dip galvanized and stainless fasteners instead. The punch list cleared on first inspection. The upfront cost difference is $800-$2,400 on a typical addition; the re-do costs triple that. Call (562) 203-4508 for an exact quote - estimates are free.
Yes, but the logistics define the build method. We use crane-set prefab wall panels, just-in-time material delivery, and phased construction to minimize street storage and neighbor impact. We’ve built detached ADUs on lots under 3,000 square feet in Maywood - the key is a contractor who plans the sequence before breaking ground, not one who improvises. Call (562) 203-4508 for an exact quote - estimates are free.
Work stops, samples go to DTSC, and we wait for clearance before setting forms. This is not hypothetical - on a 1920s bungalow near the Vernon edge, we tore out the rear quarter of the slab for a detached ADU and hit diesel-tinged soil. The testing added three weeks to permitting, but we had flagged the possibility in the original scope and built the contingency into the schedule. Most residential contractors in surrounding cities never deal with DTSC; we do, and we know the protocol. Call (562) 203-4508 for an exact quote - estimates are free.
Constantly. The 1920s-1950s concrete is typically unreinforced, 4 inches thick, with no vapor barrier, sitting on expansive soil that drains poorly toward the LA River. We see cracked slabs, efflorescence, and moisture wicking into block walls on nearly every Maywood addition. Our written quotes specify slab testing, potential underpinning, and vapor barriers as needed - not as surprises, as documented conditions. Call (562) 203-4508 for an exact quote - estimates are free.
Ready to price your project? Call (562) 203-4508 to schedule your free estimate. Grant Rowan and our team will walk your property, document existing conditions with photos, and deliver a flat written price with scope and warranty - before anyone picks up a tool. That’s Clause 1 of The Haven Standard, and it’s how we’ve kept 4,000-plus projects within a few percent of the agreed cost since 2007.
Written by Grant Rowan, Owner at Rowan Construction Group, serving Maywood and the greater Los Angeles area since 2007.