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Boral Home Additions & ADU: The Miami Owner’s Guide
We install Boral-compatible home additions and ADUs throughout Miami, with most full additions landing between $53,100 and $153,400 depending on square footage, foundation work, and finish level. Most homeowners don’t call us about the whole addition, though. They call because one part of it failed: a roofline flashing detail that leaks during summer downpours, a Boral wall panel that’s softened from sprinkler overspray, or a fascia junction that’s pulling away after a few hurricane seasons. The issue usually shows up small: a rust streak under a window, a damp corner in the ADU closet, paint that won’t stay put on one section of trim. That’s when a Boral owner in Miami starts looking for someone who actually knows the product, not just a general contractor who says “we’ll figure it out.”
One thing to be clear about up front: Penhallow Remodeling Miami is an independent remodeling contractor. We are not affiliated with Boral, and we don’t pretend to be. What we are is a team that has worked with Boral exterior systems on additions and ADUs across Miami long enough to know what holds up here and what doesn’t.
Which Boral Models This Applies To
When we talk about a “Boral addition,” we’re usually talking about the exterior cladding and trim system: Boral TruExterior siding and trim, Boral Versetta Stone, or the Boral roof tiles that many Miami additions use to match the original house. The compatibility question matters because each line has its own fastening requirements, reveal dimensions, and color-matched accessories. TruExterior trim, for example, comes in standard widths from 4 to 12 inches, and it’s not interchangeable with off-the-shelf PVC trim without adjusting your reveal spacing. If someone swapped in generic trim board on a Boral addition, the joints won’t match and the caulk lines will telegraph through within a year.
Identifying your exact Boral product is usually a matter of looking at the end grain or the back of a removed piece. TruExterior trim will have a consistent core with no foam cell structure, unlike cheaper PVC alternatives. Versetta Stone panels are 36 inches long and 8 inches tall, with a distinct interlocking tab pattern on the back. As for OEM versus aftermarket: for Boral exterior trim, we recommend OEM or a documented equivalent that matches the thermal expansion rate. That’s the compatibility gotcha most Miami homeowners don’t hear about until a “budget” replacement piece cups in the sun and pulls its fasteners loose. In our humidity, the wrong substitute shows its problems fast.
Styles & brands we work with
Signs Your Boral Home Additions & ADU Is Failing
Here’s what we see most in Miami, and what it actually means:
- Dark staining or soft spots at trim-to-siding joints. Water is getting behind the Boral trim and sitting against the sheathing. Often this is failed caulk at a butt joint, but sometimes it’s a flashing detail that was skipped during the original build.
- Visible rust streaks below trim nails or screws. The fasteners used weren’t stainless steel. In Miami’s salt air, standard fasteners bleed rust within a few seasons, and that rust stains the Boral material.
- Gaps opening at outside corners or window surrounds. Boral trim expands and contracts with temperature. If the original installer didn’t leave the correct gap at miters, corners pop open. You can’t just caulk these closed; the joint needs to be resized.
- Paint failure isolated to one section or one board. That patch is taking more moisture than its neighbors. Possibly a failing drip cap above it, possibly sprinkler head hitting it daily, possibly both.
- Pest damage along the bottom edge near grade. Even Boral’s pest-resistant material can’t stop termites from entering through a gap where the siding meets the foundation. The entry is the problem, not the material.
None of these issues fix themselves, and most get more expensive the longer they sit. Miami’s wet season has a way of turning a small flashing gap into rotted sheathing faster than you’d think.
See the difference
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AfterReplacement Cost & What’s Included
For a Boral-specific repair on an addition or ADU in Miami, you’re rarely looking at the full addition numbers. We see most Boral trim and siding repairs land between $2,360 and $7,670, which covers removing the failed sections, inspecting what’s behind them, installing the correct Boral-compatible replacement, flashing any joints properly, and painting to match. A full ADU exterior reclad runs higher, typically $10,620 to $33,040 depending on square footage and how much hidden damage we find once the old material comes off.
The price includes written line-item materials and labor before we start, not an estimate range and not a verbal ballpark. Every Boral repair we do in Miami carries our 365-Day Done Right Promise: if the fix fails inside a year, we come back and fix it at no charge. That’s in writing, on every job, before the first piece of trim is pulled. Materials we install, like Boral TruExterior, also carry their own manufacturer warranties that run alongside ours.
DIY or Call Us?
Boral exterior work isn’t in the same danger category as garage door springs or electrical panels, so there’s a small amount an owner can safely handle. You can inspect your addition’s caulk joints each spring, clear soil and debris from the bottom edge of siding, and redirect sprinkler heads that are hitting the wall. Those are legitimate maintenance items that prevent half the failures we see.
What we’d stop you from doing is pulling off a failed piece of Boral trim yourself without knowing what’s behind it. Miami homes, especially older ones in Coconut Grove where Trevor Nash has spent plenty of time, hide wiring and plumbing in unusual spots. Plus, once water damage is exposed, you need to know what’s structurally sound and what isn’t before closing the wall back up. If you’re seeing staining, swelling, or joint separation, call us at (850) 988-7559. We’ll come look, put a written number in your hand, and then pick up the tools. That’s how Trevor runs every Boral project in Miami.
FAQs
Boral TruExterior and related products should last 30 to 50 years with proper installation and maintenance, but Miami’s combination of intense UV, salt air, and seasonal downpours means the caulk joints and flashing details need attention every 3 to 5 years. The material itself rarely fails; the installation details around it are what give out first. Call (850) 988-7559 if you want a condition check.
In most cases we can repair individual boards or sections without recladding the entire addition, especially if the failure is localized to one flashing detail or one butt joint. The exception is widespread moisture damage behind the siding, which forces us to remove material until we find dry, sound sheathing. We’ll know more once we open it up, but we’ll give you an honest read before any cut is made.
A typical Boral section repair on a Miami ADU takes one to two days, including paint matching and cleanup. Larger reclads run a week or more depending on weather and what we find underneath. We give you a written arrival window and we stick to it.
We stock common Boral TruExterior trim profiles in standard widths on our service vehicles, along with the stainless fasteners and joint flashing that Boral installations require. Specialty pieces and Versetta Stone panels are ordered per job, usually arriving within a few days. We’ll tell you at the estimate whether it’s a same-day stock job or an order-and-return appointment.
A full home addition in Miami runs $53,100 to $153,400, while a complete ADU construction runs $106,200 to $259,600. Those numbers shift with foundation conditions, impact window requirements, roof tie-ins, and finish level. Call (850) 988-7559 and we’ll walk the site with you, then put a written price in your hand before anything else gets discussed.
Written by Trevor Nash, Owner, Penhallow Remodeling Miami at Penhallow Remodeling Miami, serving Miami and nearby areas.
