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Boral Home Additions & ADU: The Los Angeles Owner’s Guide
We stock and install Boral-compatible materials for home additions and ADU projects across Los Angeles, with most full additions running $53,100 to $153,400 depending on square footage, foundation work, and finish level. Most Los Angeles homeowners call us after discovering their existing addition was framed or sheathed with the wrong material for our climate, or after an older accessory structure has failed a city inspection. The good news: we can usually match Boral specs and get your project back on track within days, not months.
Here’s what you need to know about getting a Boral home addition or ADU done right in Los Angeles, from someone who’s been swinging tools here for over two decades. Luca Romano, our owner, grew up in Silver Lake back when it was still mostly working-class families and corner hardware stores, and he’s seen every way an LA addition can go sideways. Good work doesn’t need a sales pitch, it just needs to be done right.
Which Boral Models This Applies To
Boral is known in Southern California for their exterior cladding, trim, and structural sheathing products, not for pre-built addition kits. When a Los Angeles homeowner mentions a “Boral addition,” they’re usually talking about one of three things: Boral TruExterior trim and siding on an existing addition, Boral concrete roof tile on a sunroom or ADU, or Boral fiber cement sheathing behind the stucco. Each one has different compatibility rules, and matching them wrong is where we see most homeowner frustration.
The quickest identifier: Boral TruExterior trim boards are typically 3/4″ or 1″ thick with a smooth, consistent face and a slightly darker gray-brown core when cut. Boral roof tiles have a distinctive rolled profile and often carry a stamped “Boral” mark on the underside (though older tiles may have worn smooth). For sheathing, the spec that matters is thickness, usually 1/2″ or 5/8″, and it should be stamped on the panel edge. One compatibility gotcha we see often: many Los Angeles additions from the pre-2015 era used Boral’s earlier trim formulations, which don’t take paint the same way as the newer TruExterior line. You can’t just spot-patch it with whatever the big-box store carries.
Styles & brands we work with
Signs Your Boral Home Additions & ADU Is Failing
- Peeling or bubbling paint along the bottom edge of trim. Boral trim is moisture-resistant, not waterproof. If it was installed too close to grade or without proper flashing, water wicks up and pushes the paint off. In LA’s wet winters, we see this on the north side of additions first.
- Soft spots when you press on exterior walls near the roofline. This usually means the sheathing behind the stucco or siding has been holding moisture. Boral sheathing is dense, but it’s not indestructible, and a failed roof flashing above it can saturate the panel over time.
- Visible cracking on Boral roof tiles, especially near the hips and ridges. Los Angeles heat cycles expand and contract tiles every single day. After ten to fifteen years, older Boral tiles can start showing hairline cracks that eventually let water through to the underlayment.
- Trim joints opening up at the corners of your ADU. If the installer butt-joined Boral trim instead of using the correct gap and sealant, the boards will shrink and expand at different rates and pull apart. You’ll see a visible seam that widens every summer.
- A chalky residue on Boral tiles or trim. That’s the surface breaking down from UV exposure. It’s not structural failure by itself, but it means the protective layer is gone and the material is now absorbing more moisture than it should.
See the difference
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AfterReplacement Cost & What’s Included
For a Boral-related home addition or ADU project in Los Angeles, you’re looking at $53,100 to $153,400 installed, with most projects landing between $75,000 and $110,000. That range covers everything from a small 300-square-foot addition with basic Boral trim replacement and stucco work, up to a full 800-square-foot ADU with new Boral sheathing, TruExterior trim, and concrete roof tile. We also handle smaller-scope jobs like trim replacement or tile repair, which run considerably less.
What moves the number: square footage, whether we’re repairing existing Boral material or installing new, foundation work if the addition is a new build, and finish level inside. Every project gets a written price before any work starts, and that number is the number. No change orders surprise at the end, no “we found something” once the walls are open. Our 365-Day Done Right Promise covers the workmanship for a full year: if it’s not done right, we make it right.
We use OEM Boral material when it’s available and matches your existing line, and quality aftermarket equivalents when OEM is discontinued or backordered. You’ll know which one we’re quoting before you approve anything. Material partners on the wider project include KraftMaid, Cambria, and Silestone, so you’re not stuck with mystery-supplier finishes.
DIY or Call Us?
Here’s the honest split. If you’re trying to identify your Boral material or match a paint color for touch-up, you can absolutely check the manufacturer stamps and take photos. That’s smart, and it saves time when you call us. If the issue is a single piece of trim that’s pulling away and the wall behind it feels solid when you knock on it, that’s a weekend repair for someone who knows how to flash and seal correctly.
Where DIY goes wrong: anything involving roof tiles, structural sheathing, or work that requires a Los Angeles city permit. An ADU addition in Los Angeles involves building codes, setback requirements, and inspections. Get the flashing detail wrong on a Boral tile roof and you won’t see the damage until the underlayment is rotted through and the ceiling below is stained. That’s a five-figure fix from a three-hundred-dollar tile job. If you’re unsure, call (254) 272-5876 and we’ll tell you straight whether it’s a DIY job or one for a crew.
FAQs
Boral TruExterior trim and sheathing typically last 25 to 30 years in Los Angeles if installed with proper flashing and kept painted or sealed; Boral concrete roof tiles can last 40 to 50 years with maintenance. The weak points are almost never the material itself, but the installation details around it.
Yes, most Boral-related failures on a home addition or ADU can be repaired, especially if caught early, which typically costs a fraction of full replacement. The exception is when sheathing has been saturated for a long time and lost structural integrity; in those cases, replacement is the only option that holds up.
Boral trim or tile repair on an existing addition usually takes one to three days, while a full ADU build with Boral materials typically runs three to six months including permits and inspections. We’ll give you a written timeline before work starts, and you’ll get photo updates before and after so you can track progress without babysitting the job site.
We stock common Boral TruExterior trim profiles and roof tile on the truck, which means many Los Angeles repair jobs can start the same day we diagnose. For less common profiles or large ADU quantities, we order directly from Boral distributors and it typically arrives within a week. Call (254) 272-5876 and we’ll tell you what’s on hand before you schedule anything.
If your Boral addition or ADU is showing its age, or you’re planning a new one and want the materials matched right the first time, call us at (254) 272-5876 for a free estimate. Sawyer Remodeling is an independent service provider and is not affiliated with Boral, but we’ve worked with their products across Los Angeles for years and know exactly what holds up here.
Written by Luca Romano, Owner, Sawyer Remodeling at Sawyer Remodeling, serving Los Angeles and nearby areas.
