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Boral Home Additions & ADU: The Long Beach Owner’s Guide
Boral home additions and ADU construction in Long Beach typically run $45,000 to $130,000 for a finished addition, and $90,000 to $220,000 for a detached ADU, depending on square footage, foundation work, and finish level. We provide written pricing before any work starts, and we install Boral-compatible framing, sheathing, and exterior trim materials on every addition we build in Long Beach. Most owners call us because the original addition or ADU has started showing water intrusion at the roofline, separation at the wall-to-house connection, or door frames that no longer close square – all signs the original Boral materials or the connection details have aged past their useful life in coastal air.
Which Boral Models This Applies To
Boral is known for two product lines that show up in Long Beach additions and ADUs: Boral TruExterior trim and siding (a poly-ash product with a 20-year substrate warranty) and Boral roofing tiles (concrete and clay profiles). If your addition has flat, crisp trim boards around windows and at the roofline that haven’t rotted where the sprinklers hit them, that’s TruExterior. If the roof has a heavy, barrel or flat tile profile, that’s Boral roof tile. The compatibility issue that catches most Long Beach owners off guard: TruExterior trim must be fastened with specific screw patterns and painted with a breathable, 100% acrylic coating within 180 days of install. Skip the paint window, and the substrate absorbs moisture and swells at the cut ends. We check this first because it’s the most common failure we see in Belmont Shore and Naples, where the salt air and morning marine layer keep surfaces damp longer than inland.
For OEM versus aftermarket: Boral’s poly-ash trim isn’t a commodity product with a universal aftermarket equivalent. We recommend OEM TruExterior for any visible trim replacement so the profile and expansion rate match the adjacent boards. For framing and sheathing behind it, we specify Zip System or comparable engineered sheathing, which we’ve found holds up better against Long Beach’s humidity than standard OSB. Elmstead Remodeling Long Beach is an independent contractor, not a Boral dealer or affiliate, so we carry what works rather than what a single manufacturer pushes.
Styles & brands we work with
Signs Your Boral Home Additions & ADU Is Failing
- Chalky or flaking paint on the trim boards. This means the original acrylic coating has broken down and the poly-ash substrate is now exposed to UV and moisture. Once the paint film fails, water wicks into the board ends and the swelling starts. We see this on the west-facing walls of Long Beach additions more than anywhere else.
- Gaps opening between the addition wall and the main house. Houses settle, and additions settle on their own schedule. A gap wider than 1/8 inch at the transition flashing means the addition has pulled away enough that water can get behind the weather barrier. Left alone, this rots the framing and invites termites – a real concern in Long Beach’s older neighborhoods like Bluff Park.
- Doors inside the ADU that stick or have uneven reveal lines. When the floor system of a Boral addition or ADU starts deflecting or the foundation settles unevenly, the first thing you notice is a bedroom door that drags on the jamb. It’s not humidity. It’s movement.
- Cracked or loose Boral roof tiles near the valley or ridge. Long Beach gets real wind off the water, and the salt air corrodes the nails and flashings long before the tiles themselves fail. A cracked tile is cosmetic. A loose tile cluster with exposed nail holes is a leak waiting for the next winter storm.
- Musty smell in the ADU after rain. This is the tell that water is getting in somewhere and not drying out. In a Boral-built structure, the usual entry points are the trim-to-window junctions, the roofline transition, or the stucco weep screed. The smell persists because coastal air doesn’t allow full drying between storms.
See the difference
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AfterReplacement Cost & What’s Included
For a full Boral home addition in Long Beach, budget $45,000 to $130,000. That range covers everything from a 300-square-foot bump-out with a simple roof tie-in to an 800-square-foot addition with a bathroom, foundation work, and Boral trim and tile detailing. A detached Boral-clad ADU runs $90,000 to $220,000 in Long Beach, and the spread is driven by four things: whether the lot requires pier-and-beam or slab-on-grade foundation work, how far the electrical and sewer runs have to go, the finish level you choose inside, and how much site access slows the crew down. Long Beach alleys are tight, and some garage-conversion ADU projects in neighborhoods like Rose Park take longer simply because the material staging is tight.
Every Boral addition and ADU estimate from us includes a written line-item price before any work starts. You’ll see the cost of the Boral materials, the framing, the foundation, the interior finishes, and the labor, broken out separately. Graham Stein’s signature line is honest: “The price I write down on day one is the price on the invoice when we’re done.” Our 365-Day Done Right Promise covers the completed project – if something isn’t done right, we make it right.
DIY or Call Us?
There are a few things a Long Beach homeowner can safely check on their own. You can walk the exterior after a rain and look for water stains below windows. You can press on trim boards near the ground to feel for soft spots. You can run a screwdriver lightly along the bottom edge of Boral trim to see if it crumbles. What you should not do is pull trim boards off to inspect behind them, climb onto a tile roof to check flashings, or attempt to lift and reseat a settled addition corner with a bottle jack. The high-tension area of any Boral addition is the structural connection between new framing and existing house framing. Getting that wrong means water intrusion, sagging, or worse. If you’re seeing any of the failure signs above, call us at (562) 512-7086 and we’ll send a crew that knows exactly what to look for in Long Beach’s specific climate and soil conditions.
FAQs
Boral TruExterior trim carries a 20-year substrate warranty and typically lasts 25 to 30 years in Long Beach’s coastal climate when painted correctly and installed with proper flashing. Boral roof tiles can last 50 years or more. The weak point is never the material itself – it’s the installation details, the paint schedule, and the flashing at the transitions, which is why we spend extra time on those in coastal neighborhoods like Belmont Shore and Naples.
Yes, in most cases the trim, flashing, and roofline details can be repaired without rebuilding the whole addition. If the framing behind the Boral exterior is sound, we replace the failed trim boards, correct the flashing, and reseal the transitions. If water has been getting in for years and the framing is soft, the repair scope grows. We’ll write up a scope that tells you exactly what we found once we open the wall. Call (562) 512-7086 for an assessment.
A simple trim and flashing repair on an existing Boral addition takes one to three days. A full ground-up Boral-clad ADU typically takes four to seven months in Long Beach, and the biggest variable is the city’s permitting and inspection schedule, not the construction itself. We keep the same two-person crew on the job from day one to the last day so you’re never teaching a new team about your house.
We keep common Boral TruExterior trim profiles in stock at our Long Beach shop, along with the compatible fasteners, flashing, and acrylic coating systems. Specialty profiles and Boral roof tile have a lead time from the supplier, usually one to three weeks in Southern California. We’ll tell you the material lead time before we write the price, so there are no surprises about when the crew can start. Call (562) 512-7086 and we’ll check stock same day.
Written by Graham Stein, Owner, Elmstead Remodeling Long Beach at Elmstead Remodeling Long Beach, serving Long Beach and nearby areas.
