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 Lancaster
A home addition or ADU in Lancaster typically runs $45,000-$130,000 for a room addition and $90,000-$220,000 for a new detached ADU, depending on size, foundation work, and whether the property falls under the city’s 2013 solar mandate. We’re Barrett & Sons Construction, and we’ve been building in the Antelope Valley long enough to know that Lancaster isn’t like the rest of Los Angeles County. The caliche, the wind, the solar code, the HOA rules in the newer tracts off Avenue K and Avenue L – all of it changes how a job gets priced and sequenced. Call (877) 610-1318 and we’ll walk your lot with you before anyone quotes a number.
Why Barrett & Sons Construction Is Lancaster’s Preferred Home Additions & ADU Company
Tom Barrett started this company in 1998 and put his name on the truck. That still means something here. When we quote an ADU in Lancaster, the crew that shows up is Tom’s sons and their teams – not strangers dispatched from a call center. We live twenty minutes away. If something’s wrong, we want to know about it, because we’ll see you at the hardware store on Saturday.
Lancaster homeowners talk. They remember the contractor who pulled permits when the last guy said permits were optional. They remember the written change order that arrived before a single nail moved. That’s why much of our work in the 93534, 93535, and 93536 zip codes comes from referrals. The permit inspector works for you, not for me – that’s why I like him. We pull permits and get inspections signed on every eligible job, and we back it with our 90-Day Done Right Promise. One call brings Tom back.
We answer the phone live, 24 hours a day. No voicemail box. No out-of-state call center. When you call about an ADU off Avenue J or a second-story addition near Lancaster Boulevard, you get a person who knows the area and can actually show up to look at it.
Our Home Additions & ADU Services in Lancaster
ADU Design & Permitting
Lancaster’s 2013 rule that every new home include rooftop solar doesn’t just apply to houses – it reaches into ADU work on post-2013 properties. If you’re adding a detached unit to a 2015-built home in the 93584 area, the city requires either extending the existing PV system or adding a dedicated array tied to the new structure’s electrical panel. That’s a load-calculation and permitting step that doesn’t exist in Palmdale or Santa Clarita. We handle the design, the net-metering paperwork, and the utility sign-off so the ADU doesn’t stall at final inspection.
Garage Conversion ADU
A garage conversion in Lancaster runs $30,000-$80,000 depending on whether we’re working with an attached garage on a 1960s ranch home near the 93534 corridor or a newer stucco tract home off Avenue K-8. The older homes usually need more electrical work and insulation brought up to current code. The newer ones trigger the solar recalc we mentioned. Either way, we handle the structural tie-in, the utility connections, and the paperwork so the conversion counts as a legal dwelling unit – not a “bonus room” that bites you at resale.
New Detached ADU
A new detached ADU in Lancaster is a full build: footings, framing, roofing, electrical, plumbing, and finish. It’s also where caliche becomes your biggest unknown cost. In the 93534-93535 neighborhoods, caliche sits within 18 inches of the surface across much of the valley floor. A standard footing trench can turn into a pneumatic-hammer job, and that changes the excavation line before concrete ever shows up. We price it honestly up front, and if the ground surprises us, you get a written change order before the hammer comes out – not a surprise invoice at the end.
Junior ADU & Interior Conversion
A junior ADU – typically a bedroom-plus-kitchenette conversion inside the existing footprint – is the most budget-conscious way to add rental or in-law space in Lancaster. These jobs often run well under a full addition and can usually be permitted faster. In the newer 93536 tracts, we coordinate with your HOA’s architectural committee early, because interior conversions still trigger their review in many of the master-planned communities west of the freeway.
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 Lancaster
We install Simonton and Ply Gem windows and doors on our Lancaster additions and ADUs because they hold up to Antelope Valley sun and wind better than builder-grade frames. We stock common sizes locally so lead times stay short when a project is already underway. PGT impact-rated windows are another option we recommend for homeowners off high-wind corridors near Tehachapi Pass. We don’t install materials you can’t look up. If we’re putting it on your house, you should be able to search the brand and read its specs yourself.
Common Home Additions & ADU Problems We See in Lancaster Homes
- Solar load conflicts on post-2013 homes. Adding square footage without re-calculating the existing array’s output for the new demand is the most common way ADU permits die at final inspection in Lancaster. The utility rejects the net-metering change order, and the owner is stuck holding a finished unit that can’t get its sign-off.
- Caliche blowouts on excavation. In the older 93534 and 93535 neighborhoods, caliche can sit within 18 inches of the surface. A trench for ADU footings or a sewer lateral becomes a pneumatic-hammer job, and a bid that assumed soft dirt goes out the window. We scope for caliche risk up front.
- Wind-load failures on second-story additions. The Antelope Valley wind corridor, fed by Tehachapi Pass, imposes real structural requirements on framing and cladding. A second-story addition framed without accounting for those loads fails inspection and triggers change orders for shear-wall and hold-down hardware. We design for the wind from day one.
- HOA architectural-review stalls in 93536. Newer master-planned communities west of the freeway often require HOA architectural approval before a detached ADU or room addition can even be submitted for city review. Homeowners who skip that step lose weeks. We sequence the HOA review first.
Pricing for Home Additions & ADU in Lancaster, CA
Here’s what we’re seeing in Lancaster right now, line-item by line-item. A room addition runs $45,000-$130,000 depending on whether it’s a single-story bump-out or a full second-story addition framed for Antelope Valley wind loads. A detached ADU runs $90,000-$220,000 once you factor in site prep, solar integration if the home was built after 2013, and caliche excavation risk. Garage conversions are the most economical legal dwelling unit at $30,000-$80,000. We quote fixed pricing with written change orders before any scope change touches the job. No surprise invoices. The allowance that isn’t on paper is a surprise waiting for a date.
| Project Type | Lancaster Price Range |
|---|---|
| New Detached ADU | $90,000-$220,000 |
| Garage Conversion ADU | $30,000-$80,000 |
| Room Addition | $45,000-$130,000 |
Call (877) 610-1318 for a free estimate. We’ll come out, look at your lot, check for caliche, check your solar array if you have one, and give you a written number you can hold us to.
We Also Serve Cities Near Lancaster
We run crews to Quartz Hill, Palmdale, Sun Village, and Acton regularly. If you’re in one of those spots and looking for Home Additions & ADU work done right, call us. And if you’re in Lancaster itself, we’re already nearby.
Serving Lancaster, CA - Our Local Coverage Area
We’re based in the Lancaster 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 Lancaster
If your Lancaster home was built after 2013, any ADU addition triggers a requirement to either extend the existing rooftop PV system or add a dedicated array tied to the new structure’s electrical panel. That adds design, permitting, and load-calculation work that typically runs $3,000-$8,000 depending on system size and whether the existing array has spare capacity. It also means the utility signs off on a net-metering change order before your ADU gets its final inspection. Call (877) 610-1318 and we’ll tell you exactly what your existing system will handle.
Yes, in most of the newer master-planned communities in the 93536 corridor, a detached ADU requires architectural committee approval before the city will accept your application. The HOA review typically covers setbacks, exterior materials, rooflines, and color palettes. We sequence that review first, because nothing else moves until they sign. Pulling a city permit without HOA sign-off is a fast way to lose weeks and anger the neighbors who sit on that committee.
Yes, but only if the addition is done improperly or without permits. Most builder warranties include clauses about unauthorized modifications, and unpermitted structural work is the fastest way to void what’s left of your coverage. A permitted addition done by a licensed contractor with inspections signed typically keeps the original warranty intact for areas we didn’t touch. We pull permits on every eligible job specifically so you don’t lose that protection. Call us and we’ll check your warranty language before you sign anything.
Caliche is the rock-hard calcium carbonate hardpan that sits just inches to a few feet below the surface across much of Lancaster, especially in the older 93534 and 93535 areas. Footing trenches that would be straightforward dirt work in Los Angeles often require pneumatic hammers or saw-cutting here. That can add $2,000-$8,000 to excavation costs on a detached ADU, depending on how deep and how wide the caliche runs on your specific lot. We test for it before we quote, so it doesn’t show up as a surprise. Call (877) 610-1318 for a free site walk.
Plan on 6-12 weeks for the permitting and inspection cycle on a typical ADU in the 93584 area, assuming no solar-load complications and no HOA review drag. The structural inspections move fastest. The utility sign-off on solar-integrated ADUs is usually the longer pole, especially if a net-metering change order has to go back for correction. We schedule inspections back-to-back where the city allows it, and we don’t leave a job until the final sign-off is in hand. Call (877) 610-1318 if you want us to check current city review times for your specific project.
Get Your Lancaster Addition or ADU Priced Right
Free estimates. Written change orders. Permits pulled and inspections signed. The 90-Day Done Right Promise on every job. Call (877) 610-1318 and ask for Tom. We’ll come out to your Lancaster lot, look at the dirt, check the solar, and give you a number in writing before you commit to anything.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving Lancaster and the Antelope Valley since 1998.