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

Fast, Reliable Home Additions & ADU Across Hacienda Heights

Hacienda Heights sits on some of the most distinctive terrain in LA County: an unincorporated island in the Puente Hills where nearly every meaningful addition or ADU project runs through LA County Building and Safety, and where sloped, cut-and-fill lots routinely demand engineered retaining walls and hillside foundations before the first framing member goes up. If you’re planning a home addition or ADU in Hacienda Heights, the realistic price range is $45,000-$130,000 for a room addition and $90,000-$220,000 for a new detached ADU, with garage conversions running $30,000-$80,000 depending on utilities and foundation work. At Barrett & Sons Construction, we’ve built and remodeled on these hillsides long enough to know that a plan that works in La Puente does not automatically work off Colima Road. Call (877) 610-1318 and we’ll walk your lot before we quote a dollar.

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

Tom Barrett puts his name, address, and license number on every contract, so a Hacienda Heights homeowner can verify who they’re hiring before they sign. That matters in a community where the LA County plan-checker will scrutinize your hillside grading plan more aggressively than any neighboring incorporated city would. We don’t dodge that review; we prepare for it. Every project we run through Hacienda Heights gets permits pulled and inspections signed, with every scope change and allowance adjustment issued as a written change order before work proceeds. There’s a reason people off Turnbull Canyon Road and along Skyline Drive call us back for their second and third projects: the crew that shows up is the same crew that quoted the job, and Tom’s sons are on-site most days, not subcontracted strangers.

Our customers in the 91745 ZIP code tell us the same thing again and again: they’d rather pay for a contractor who answers his own phone than save a few dollars on one who disappears after the deposit. We’ve held that line since 1998. The 90-Day Done Right Promise is written on every contract. If something isn’t right, one call brings Tom back. No fine print, no runaround.

Our Home Additions & ADU Services in Hacienda Heights

ADU Design & Permitting

Because Hacienda Heights is unincorporated, every ADU permit is issued by LA County Building and Safety under Title 26, and county plan-checkers enforce hillside grading ordinances, including Appendix J, far more rigorously here than in La Puente or Whittier. We draw and submit plans sized for hillside lots, not flat-lot city work, so your permit application doesn’t stall in corrections for months. Our Home Additions & ADU team handles the entire package: drawings, structural calculations, grading plans, and county submittals.

Garage Conversion ADU

Many Hacienda Heights garages were built into the slope itself, which means a garage conversion here often involves retaining wall inspection, drainage correction, and foundation reinforcement before we ever frame an interior wall. A garage conversion in Hacienda Heights typically runs $30,000-$80,000, and the biggest cost driver is usually what’s underground, not what’s inside. We inspect the existing slab and the hillside behind it before we quote, because the last thing anyone wants is a bedroom added to a garage that’s slowly sliding downhill.

New Detached ADU

Building a new detached ADU on a Hacienda Heights hillside lot means engineered footings, proper drainage, and often a retaining wall where the pad meets the hill. Our ADU construction in Hacienda Heights runs $90,000-$220,000 for a complete unit, with soil engineering as a non-negotiable line item, not an optional upgrade. The county will ask for it anyway. We plan for it from the start. If you’re also considering interior work on your main house, we handle Kitchen Remodeling in Hacienda Heights alongside ADU projects so one crew manages the whole property.

Junior ADU & Interior Conversion

A junior ADU, often carved from an existing bedroom or bonus room, is the fastest and least expensive way to add rentable square footage in Hacienda Heights. These conversions typically start around $45,000 when the space already has a door to the outside and adequate egress. Interior conversions on slab foundations still need county sign-off, and we pull that permit every time. We also handle Bathroom Remodeling in Hacienda Heights for ADUs and JADUs, because a permitted ADU without a properly vented, permitted bathroom is just an expensive storage room.

Trusted Brands We Service in Hacienda Heights

We don’t show up with mystery materials off a van. On addition and ADU projects in Hacienda Heights, we regularly install Simonton windows for their wind and heat performance on exposed hillside lots, and Ply Gem or PGT openings when a project calls for higher impact ratings. These are brands you can look up, with published performance specs, not whatever was on sale at the yard that week. Because our crews work Hacienda Heights regularly, we know which suppliers along the 60 corridor stock what we need, which means fewer days waiting on backordered windows while your framing sits exposed to the Puente Hills wind.

Common Home Additions & ADU Problems We See in Hacienda Heights Homes

• Aging cut-and-fill retaining walls. The original concrete block walls installed during the 1960s-1980s building boom are reaching the end of their service life on many hillside parcels, and a new addition often triggers a county requirement to repair or replace the wall that’s been holding up the backyard for forty years.
• Expansive clay soils heaving slabs and footings. The shrink-swell cycle in Hacienda Heights’s clay soils cracks slabs and shifts foundations over time. Any addition tied to an existing slab needs a soil evaluation first, or the new work will simply inherit the old movement.
• Hillside drainage directing water toward the foundation. Hot, dry summers followed by concentrated wet-season rain events send water downslope in a hurry. Poor drainage is often why the original patio or garage slab cracked, and it has to be fixed before an addition goes up, not after.
• Unpermitted previous work discovered at plan check. A surprising number of Hacienda Heights homes have unpermitted additions or patio enclosures from decades past. When we pull your new permit, the county will see that unpermitted work on record. We handle the correction process honestly: here’s what exists, here’s what the county requires, here’s the written change order.

Pricing for Home Additions & ADU in Hacienda Heights, CA

We Also Serve Cities Near Hacienda Heights

Our crews work throughout Hacienda Heights and the surrounding communities, including La Puente, Valinda, Avocado Heights, and West Puente Valley. If you’re in one of those neighboring cities and planning an addition or ADU, the same crew, the same written change order policy, and the same 90-Day Done Right Promise apply. Call (877) 610-1318 and we’ll schedule your free estimate.

FAQs - Home Additions & ADU in Hacienda Heights