Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Fast, Reliable Home Additions & ADU Across Glendale
Home additions and ADU construction in Glendale run $45,000-$130,000 for room additions and $90,000-$220,000 for detached ADUs, with most projects taking 4-8 months from permit to final inspection. We’re familiar with Glendale’s specific conditions - from the hillside fire zones above Adams Hill to the Craftsman stock in Rossmoyne - and our Home Additions & ADU team coordinates dispatch from our Los Angeles office with crews serving Glendale neighborhoods directly. Call (213) 221-0788 to schedule your free estimate; we deliver a written price before any work starts, every time.
Why Rowan Construction Group Sherman Oaks Is Glendale’s Preferred Home Additions & ADU Company
We’ve completed additions and ADUs across Glendale’s distinct zones - flatland neighborhoods near Brand Boulevard, the hillside streets of Adams Hill, and the winding lots of the Verdugo foothills. Our crews know the difference between a standard L.A. County permit set and the Chapter 7A ignition-resistant assemblies CAL FIRE requires here.
Glendale customers find us through the same channels they research appliances: they read our three-star reviews alongside our five-star ones, then call to test whether we’ll put a number in writing. We do. Under Clause 1 of The Haven Standard, the price is written before anyone starts. That discipline, maintained across 4,000-plus projects since 2007, is why our jobs finish within a few percent of the agreed cost.
Response time to Glendale is same-day for estimates in most cases. A live person answers calls 24/7, and every visit produces a documented photo record - included, not optional - so you have evidence of what was found and what was done.
Our Home Additions & ADU Services in Glendale

ADU Design & Permitting
Glendale’s ADU permitting runs through the city’s Planning and Community Development Department, with additional review for hillside lots in Very High Fire Hazard Severity Zones. We prepare the full permit set - site plan, floor plans, elevations, structural calculations - and flag Chapter 7A requirements before submission. A typical detached ADU in Glendale costs $90,000-$220,000, with design and permitting fees adding $8,000-$15,000 to the construction budget. We handle the fire department plan check, the geotechnical coordination if your lot requires it, and the inspection scheduling so you’re not chasing sign-offs.

Garage Conversion ADU
Garage conversions in Glendale run $30,000-$80,000 and represent the fastest path to rental income or multi-generational space. The catch: many Glendale garages sit on sloped driveways with inadequate foundation depth, or share a roofline with the main house in ways that trigger full fire-separation requirements. We assess the existing slab, the roof structure, and the utility routing before quoting - no “call for a price” here. In the Verdugo foothills above Adams Hill, we built a detached ADU on a steep lot that needed a geotech report and an engineered retaining wall before we could pour footings. We swapped the owner’s builder-grade vinyl windows for impact-rated units and used non-combustible siding to meet Chapter 7A, set a draw schedule tied to inspection sign-off, and closed the punch list after the final.

New Detached ADU
Detached ADUs in Glendale face the strictest scrutiny - setback rules, utility trenching across established landscaping, and for hillside lots, mandatory geotechnical reports and engineered retaining walls. We coordinate with Glendale’s Public Works for sewer lateral capacity and with LADWP or Glendale Water & Power for electrical service sizing. The $90,000-$220,000 range reflects foundation type (slab vs. raised), roofing material, and whether you’re incorporating prefabricated elements from brands like Dvele or Plant Prefab, both of which we’ve specified for Glendale projects where speed and code compliance matter.

Second Story Additions
A 1920s Rossmoyne bungalow we added a second story to required us to reinforce the load-bearing frame and sister the original floor joists; the owners praised the formal entry vestibule and oversized dining room we matched to their family’s use. Second-story work in Glendale’s older stock demands structural analysis of the original foundation and framing - many of these homes were built with redwood or Douglas fir that has degraded, or with connections that don’t meet current seismic standards. We engineer for the addition’s weight, the lateral load, and the tie-down requirements that Glendale’s building official enforces. Typical range: $45,000-$130,000 depending on square footage and structural complexity.

Junior ADU & Interior Conversion
Junior ADUs - conversions within the existing footprint, with a kitchenette and separate entrance - suit Glendale’s smaller lots where setbacks prevent detached construction. We work within the California HCD guidelines and Glendale’s local amendments, addressing parking relief, owner-occupancy requirements, and utility metering. These run toward the lower end of the addition spectrum, typically $45,000-$85,000.

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.
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AfterTrusted Brands We Service in Glendale
We source across fifty-plus vetted brands, and for Glendale’s fire-zone requirements we regularly specify impact-rated windows, Class A fire-rated roofing, and non-combustible cladding systems. That includes prefabricated ADU manufacturers like Mighty Buildings and Boxabl, whose panels meet Chapter 7A standards out of the factory, cutting field modification and inspection risk. We don’t inflate quotes with brand premiums - the written price reflects actual material cost, and we stock common Glendale-specified items locally to avoid the delays that stretch project timelines.
Common Home Additions & ADU Problems We See in Glendale Homes

- Starting hillside work without geotechnical review. Glendale’s steep lots in the Verdugo foothills routinely require engineered retaining walls and soils reports before footing placement. Skipping this step stalls permits and can trigger stop-work orders.
- Treating a builder warranty as a free pass. Altering load-bearing elements or performing unpermitted rough-in on newer Glendale homes voids coverage. We see owners surprised when the builder denies a claim after a DIY garage conversion.
- Ignoring Chapter 7A in VHFHSZ zones. Standard vents or combustible cladding on hillside ADUs trigger inspection failures. Ember-resistant vents, fire-rated assemblies, and non-combustible exterior materials are mandatory - not upgrades.
- Letting HOA architectural review lapse. Master-planned Glendale communities enforce exterior colors, footprint limits, and sight-line rules. Unapproved ADU designs can force removal or fines, and we coordinate submittals before construction starts.
Pricing for Home Additions & ADU in Glendale, CA
We put the number in writing before anyone picks up a tool. Here’s what Glendale projects typically run:
| Project Type | Price Range in Glendale |
|---|---|
| Home Addition (room or second story) | $45,000-$130,000 |
| ADU Construction (detached) | $90,000-$220,000 |
| Garage Conversion ADU | $30,000-$80,000 |
| Window Replacement (impact-rated for VHFHSZ) | $4,500-$15,000 |
| Roof Replacement (Class A fire-rated) | $8,000-$20,000 |
What moves the number: hillside geotechnical requirements, fire-zone material upgrades, utility trenching distance, and whether the existing structure needs seismic reinforcement. Every quote is flat-priced with a written scope and a written warranty. No change proceeds without a signed change order - the discipline that has kept our projects within a few percent of the agreed cost since 2007. Call (213) 221-0788 for your free estimate; bring a competitor’s written quote and we’ll review it line by line at no charge.
We Also Serve Cities Near Glendale

Our crews work across the Los Angeles metro, including Home Additions & ADU in Glendale and neighboring Burbank, North Hollywood, Studio City, and West Hollywood. Each city carries its own permit rhythms and code layers - Burbank’s flat terrain skips the Chapter 7A requirements that Glendale hillside lots trigger, for instance - and we adjust our submittals accordingly.
Serving Glendale, CA - Our Local Coverage Area
We’re based in the Glendale 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 Glendale

Yes, if your lot sits in a Very High Fire Hazard Severity Zone or has slope exceeding 15%, Glendale typically requires a geotechnical report and engineered retaining wall before footing approval. We coordinate this during design, not after permit submittal, to avoid delays. Call (213) 221-0788 to review your specific lot conditions - estimates are free.
Replace single-pane windows with impact-rated units, upgrade to a 200-amp electrical panel, and install fire-resistant exterior cladding if you’re in a VHFHSZ zone. These three address Glendale’s specific climate and code pressures while preserving builder warranty coverage when done with permitted, licensed work. Call (213) 221-0788 for a line-item quote on your home.
It can, if the work alters load-bearing elements or is performed without permits. We engineer our additions to integrate with existing structure, pull all required permits, and document the work so your warranty coverage remains intact where possible. Call (213) 221-0788 and we’ll review your warranty documents during the estimate.
Most master-planned Glendale HOAs require architectural review board approval for exterior modifications, setback compliance, and color/material matching before city permits are filed. We prepare the HOA submittal package concurrently with the permit set to prevent construction stops. Call (213) 221-0788 - we’ll coordinate both reviews.
A detached ADU in Glendale runs $90,000-$220,000, while a garage conversion runs $30,000-$80,000. The gap reflects foundation work, utility trenching, and fire-separation requirements for detached units. Hillside lots add geotechnical and retaining wall costs that flatland garage conversions avoid. Call (213) 221-0788 for an exact quote on your property - estimates are free.
Written by Grant Rowan, Owner at Rowan Construction Group, serving Glendale since 2007.







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