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Boral Home Additions & ADU: The San Antonio Owner’s Guide
If you’re planning a home addition or ADU and want Boral-compatible materials and construction methods, a full project in San Antonio typically runs $45,000 to $130,000 for an addition, and $90,000 to $220,000 for a detached ADU. We’re Mason Remodeling Co San Antonio, and we handle Boral siding, trim, and exterior finishing products on these jobs every season. The most common way homeowners find us is mid-project, when they realize the original contractor specified Boral but can’t get the materials or doesn’t know how to detail them properly around San Antonio’s clay-heavy soil and humidity swings. That’s where we come in.
Boral isn’t a single product line. It’s a family of engineered wood and polymer trim, siding, and decorative exterior products that perform differently here than they do in drier climates. What fails first in San Antonio is almost always an installation detail, not the material itself. We’ll walk through what to look for and what a correct install actually costs.
Which Boral Models This Applies To
Boral’s product lineup includes TruExterior siding and trim, Kleer trimboards and sheet goods, and Versetta Stone panels. Each has different fastening requirements, expansion tolerances, and paint adhesion characteristics. If you’re matching existing Boral on a San Antonio addition or ADU, you need to know which line you have before ordering anything.
Here’s the compatibility gotcha most people miss: TruExterior and Kleer are not interchangeable for trim applications. TruExterior is a poly-ash product that cuts and fastens more like wood, while Kleer is cellular PVC. Both take paint well, but the reveal sizes, corner post dimensions, and required gap spacing differ. We measure the existing board width, check the profile shape (square edge vs. shiplap vs. nickel gap), and read the manufacturer stamp on the back of any removed piece before ordering. Boral stamps are usually on the rear face or along the factory edge. Aftermarket generic trim can work in low-visibility areas, but near windows, door casings, and horizontal band boards, we spec OEM Boral so the expansion and contraction rates match the existing run. When we install Boral on an ADU shell, we stock standard 4/4 and 5/4 trim boards, 1x and 2x material, plus corner boards and skirt boards on the truck. Sheet goods for soffits and porch ceilings are ordered by the job.
Styles & brands we work with
Signs Your Boral Home Additions & ADU Is Failing
- Paint blistering or peeling within two years. Boral products hold paint well, but if the installer didn’t wipe down factory edges or used a low-quality primer, San Antonio’s humidity will lift the finish fast.
- Gaps opening at butt joints. Boral trim expands and contracts with temperature. Joints need a specific gap and a high-quality adhesive or a shiplap overlap. If you see daylight between boards, the original installer cut them tight in winter.
- Wavy runs along long walls. Boral boards need fasteners at the manufacturer’s spacing, typically every 16 inches or tighter on long runs. Skipped fasteners let the board bow between studs.
- Water staining at the bottom edge of siding. This usually isn’t a Boral failure; it’s missing flashing or an improper kickout where a roof meets a wall. The product is doing its job. The flashing wasn’t.
- Caulk pulling away from trim around windows and doors. If the installer used standard acrylic caulk instead of a high-quality elastomeric, San Antonio’s heat cycles will break the bond within a season or two.
See the difference
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After
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AfterReplacement Cost & What’s Included
Most Boral repair work on an existing San Antonio home addition lands between $1,200 and $8,000, depending on how much trim or siding needs to come off. A full new addition or ADU with Boral exterior finishing falls in the $45,000 to $130,000 range for the addition shell, and $90,000 to $220,000 for a complete detached ADU with finishes.
- Trim board replacement (partial, one wall section): $1,200 to $3,500
- Full re-side with Boral TruExterior on an ADU: $12,000 to $28,000
- Complete new home addition with Boral exterior: $45,000 to $130,000
- Full ADU construction with Boral finishes: $90,000 to $220,000
The range depends on access, two-story vs. single-story, whether we’re pulling permits, and whether the framing underneath needs attention before new material goes on. Every project gets a written price before work starts. That includes materials, labor, disposal, and the permit if one’s required. Isaac Pruett gets the scope right on the first walkthrough, so the number we write down is the number you pay.
DIY or Call Us?
You can inspect Boral siding and trim safely. Walk the perimeter with a flashlight, look for gaps at joints, check caulk lines around openings, and note any spots where water is pooling or staining. You can also repaint Boral products yourself if the surface is clean and the product was installed correctly.
Replacing Boral siding or trim on a second-story wall, around window flashing, or where a roof meets a wall is not a weekend project. Getting the flashing wrong means water inside the wall cavity, and in San Antonio that becomes rot and mold fast. Cutting Boral products creates fine dust that needs a proper mask, and fastening patterns matter more than most homeowners expect. Call (254) 269-5071 if you’re unsure. We’ll tell you honestly whether it’s a repair or a replacement, and we’ll put the price in writing before you decide anything.
FAQs
Boral TruExterior and Kleer products carry 20 to 25 year warranties from the manufacturer, and in practice they hold up well for that long in San Antonio’s climate when installed correctly. The installation details matter more than the product itself. Call (254) 269-5071 for an exact quote on your project, and we’ll assess your existing install at no charge.
Small gouges and nail pops can often be repaired with Boral’s recommended patching compound and repainting, but cracked boards, failed joints, or sections with water infiltration need replacement. We’ll tell you which one you have. Estimates are free, so call (254) 269-5071 to set up a walkthrough.
Most partial replacements on an existing San Antonio home take one to three days once materials are on site. A full new addition or ADU with Boral finishes runs on the project schedule, typically eight to twenty weeks depending on scope and permit timelines. Call (254) 269-5071 for a written schedule before work starts.
We stock standard Boral trim boards, corner boards, and fasteners at our San Antonio yard, and we order sheet goods and specialty profiles direct from Boral distribution for each job. That means a repair can usually start within a few days of the written estimate. Call (254) 269-5071 to confirm availability for your specific Boral line.
Know who’s coming, know what it costs, know it’s covered, that’s the whole job before the job starts.
Written by Isaac Pruett, Owner, Mason Remodeling Co San Antonio at Mason Remodeling Co San Antonio, serving San Antonio and nearby areas.
