Home Additions & ADU in Lancaster - One Fixed Price, Permits Handled

Fast, Reliable Home Additions & ADU Across Lancaster

Home additions and ADU construction in Lancaster, CA typically run $45,000 to $130,000 for a room addition, and $90,000 to $220,000 for a new detached ADU. Those are real numbers for this market, not national averages. If you live in the 93534, 93535, 93536, or 93539 zip codes, you already know the Antelope Valley doesn’t build like the coast does. The caliche hardpan under most Lancaster lots turns what should be a simple footing dig into a jackhammer job, and the wind corridor off Tehachapi Pass means your framing and shear walls have to be overbuilt from day one. Call Barrett & Sons Construction at (877) 610-1318 and we’ll walk your lot with you, point at where the caliche sits on your property, and give you a written scope and price before you commit to anything.

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Why Barrett & Sons Construction Is Lancaster’s Preferred Home Additions & ADU Company

Barrett & Sons Construction has been owner-operated since 1998, and Tom Barrett’s name, address, and license number are published for anyone to look up. That matters in Lancaster, where a lot of homeowners have been through the wringer with contractors who quote one number on the phone and show up with a different story. Our crew includes Tom’s sons, not strangers dispatched from somewhere else. When we say we’ll be on your job on Monday, the person who shakes your hand at the hardware store on Saturday is the same person who’s there Monday morning.

We’ve worked across Lancaster’s older ranch tracts around 93534, where 1950s slab foundations are now dealing with expansive desert soil movement, and we’ve added second stories and ADUs in the newer 93536 corridor where stucco and wood-frame homes are hitting their 25-year envelope repair window. Each neighborhood has different setback rules, different soils, and different HOA overlays. We know the difference between what Lancaster’s building department will flag on a garage conversion versus what it lets slide, because we’ve sat in that permit office more times than we can count.

Every job we do in Lancaster comes with the written 90-Day Done Right Promise. If something isn’t right, one call brings Tom back. That’s not a marketing line. It’s written on the contract, and it’s why our Lancaster customers refer us to their neighbors on the west side and out toward Sun Village.

Our Home Additions & ADU Services in Lancaster

ADU Design & Permitting

Lancaster has some of the most specific ADU rules in Southern California, and they interact with the city’s 2013 solar mandate in ways that surprise people. Every new detached ADU in Lancaster triggers the solar-ready framing requirement, which means your roof pitch and truss layout need to accommodate photovoltaic loads from the beginning. We design ADUs with that baked in, not bolted on later. We pull permits on every eligible job, and we handle the drawings, the structural calculations, and the planning department meetings so you don’t have to sit through them.

Garage Conversion ADU

A garage conversion in Lancaster typically runs $30,000 to $80,000 depending on whether the existing slab is usable or whether caliche made the original pour too thin for habitable space. In the older 93534 neighborhoods, many garages were built as carports that got enclosed informally decades ago. Those need full legalization before they can become a permitted ADU, which means bringing the slab, electrical, and insulation up to current code. We do that work in-house, and we write every scope change down before it happens.

New Detached ADU

Building a new detached ADU in Lancaster means full site work, and site work here means caliche. Between the hardpan excavation, the high-wind structural requirements, and the desert temperature swings that push insulation specs above coastal standards, a Lancaster ADU is a different build than the same square footage in Palmdale or Santa Clarita. We’ve cut caliche with saws and broken it with pneumatic hammers on lots all over the valley. We’ll walk your property, show you where the hardpan sits, and tell you honestly what your excavation budget needs to be before we sign anything.

Junior ADU & Interior Conversion

A junior ADU, or a conversion of an existing interior space like a bonus room or a large laundry room, is often the fastest and least expensive path to a rentable or multigenerational living space in Lancaster. These projects usually fall in the $45,000 to $130,000 range depending on how much plumbing and electrical you need to add. We’ve converted spare bedrooms into kitchenette-and-bath JADUs in Sun Village and Quartz Hill, and we know which Lancaster neighborhoods have floor plans that convert cleanly and which ones fight you every step.

If your addition plans touch the kitchen or a bathroom at the same time, we also handle Kitchen Remodeling in Lancaster and Bathroom Remodeling in Lancaster as part of the same project. Combining scopes under one permit saves you money on mobilization and keeps the crew count down on your property.

Trusted Brands We Service in Lancaster

We install materials you can look up, not mystery brands off a van. On Lancaster additions and ADUs we regularly frame with Simonton windows and Ply Gem exterior products, both of which hold up to the Antelope Valley’s UV exposure and 105-degree summers better than most budget lines. Our crews stock the common sizes and flashings locally, which means when a window gets cracked during a wind event or a change order calls for a different rough opening, we’re not waiting on a freight order from out of state. For anyone planning a detached ADU with taller glazing or a sunroom on the south side, PGT’s impact-rated glass is worth a serious look given the wind corridor we build in.

Common Home Additions & ADU Problems We See in Lancaster Homes

• Caliche blowouts on excavation budgets. The calcium carbonate hardpan under much of Lancaster sits anywhere from a few inches to a couple feet below the topsoil. What looks like simple dirt work on the estimate becomes saw-cutting and breaker work on day two. If your previous contractor’s excavation number changed without warning, that’s what happened. We test-dig before we quote.
• Slab movement in the older 93534 and 93535 ranch tracts. Many 1950s and 1960s homes in Lancaster sit on original slabs that were poured before modern expansive-soil practices. Adding square footage means tying into those slabs, and sometimes that means a structural engineer signs off first. We don’t skip that step, because the inspector here won’t let you.
• Underbuilt shear walls from the pre-wind-code era. Lancaster’s position in the Tehachapi-fed wind corridor has tightened framing requirements considerably over the decades. When we open up a wall on a 1960s tract home to tie in an addition, we often find shear nailing that wouldn’t pass today. That has to be corrected before inspection, and we write it up as a change order before we touch it.
• Solar-ready roof integration on every new ADU. Because Lancaster’s 2013 ordinance made solar mandatory on new residential construction, a detached ADU roof has to be engineered for panel weight and layout from day one. We’ve seen plans get kicked back because the truss package didn’t account for photovoltaic loads. We design it right the first time.

Pricing for Home Additions & ADU in Lancaster, CA

We Also Serve Cities Near Lancaster

From our Lancaster jobs we regularly run crews to Home Additions & ADU in Lancaster neighbors like Quartz Hill, Palmdale, Sun Village, and Acton. Dispatch and scheduling are coordinated from the Barrett & Sons office; the crews working in Lancaster live and work right here in the valley. You’ll see the same faces on your job that you’d see at the True Value on Sunday.

FAQs - Home Additions & ADU in Lancaster