Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
James Hardie Home Additions & ADU: The Fort Lauderdale Owner’s Guide
We install James Hardie siding and trim on home additions and ADUs throughout Fort Lauderdale, with most projects landing between $45,000 and $130,000 depending on size, foundation work, and the Hardie product line you choose. The conversation usually starts when a homeowner notices swelling, cracking, or paint failure on an existing addition and realizes the siding wasn’t installed to James Hardie’s published specs the first time around. What you’re really dealing with is a weatherproofing system that has to stand up to salt air, hurricane season, and relentless humidity, and when any part of that system fails, the fix often means pulling siding back to the sheathing and doing it right.
We stock James Hardie plank, panel, trim, and soffit on our trucks, and our crews are trained on the exact fastening patterns and clearance requirements Hardie mandates for coastal climates like ours. Mason Remodeling Co Fort Lauderdale is an independent remodeling contractor, not a James Hardie dealer or affiliate. That matters because it means we’ll tell you the straight truth about what failed, whether it’s a product issue or an installation error, and what it costs to fix it for good.
Which James Hardie Models This Applies To
This guide covers the full James Hardie exterior product range used on additions and ADUs in Fort Lauderdale: HardiePlank lap siding (smooth and cedar-grain textures, 4-inch through 8-1/4-inch exposures), HardiePanel vertical siding (4×8 and 4×10 sheets), HardieTrim boards (3/4-inch thick, widths up to 12 inches), HardieSoffit, and HardieShingle. Each line has specific installation requirements that vary by climate zone, and Fort Lauderdale falls in James Hardie’s coastal/humid category, which changes the game on clearances and fastener type.
Here’s the compatibility gotcha most homeowners never hear about: HardieTrim and HardiePlank are not interchangeable thicknesses. Trim is 3/4 inch thick; plank is 5/16 inch. When a contractor butts them together without a trim-to-plank transition detail, water gets behind the thinner plank and rots the sheathing within a few seasons, especially in Victoria Park and Rio Vista where older homes have original framing that’s less forgiving of moisture intrusion. We check for this on every inspection.
OEM versus aftermarket for James Hardie means staying with genuine Hardie products. James Hardie’s 30-year limited non-prorated substrate warranty applies only when you use their boards, their flashing recommendations, and their published fastening schedule. Generic fiber cement from other manufacturers won’t match the texture, color, or durability of what’s already on your home, and mixing brands voids the warranty. We don’t do it.
Styles & brands we work with
Signs Your James Hardie Home Additions & ADU Is Failing
- Swelling or buckling at board ends near corners and windows. This happens when installers butted HardiePlank tight against trim instead of leaving the required 1/8-inch gap for expansion. Once boards swell, the damage is done and those boards need replacement.
- Paint peeling in sheets, not chips, within three to five years. Hardie products come with a baked-on primer, but if siding was stored on a Fort Lauderdale job site without proper ventilation, moisture got into the boards before installation. Repainting won’t fix it.
- Visible rust stains running down from fastener heads. Coastal air eats electro-galvanized nails in five years. James Hardie requires hot-dip galvanized or stainless steel fasteners within three miles of the coast, which covers all of Fort Lauderdale east of I-95.
- Soft spots or a hollow sound when you tap the sheathing behind HardiePanel. This means water is getting behind the panel through an unflashed window or door opening. By the time you hear it, that sheathing is gone.
- Caulk lines at trim joints cracking and separating every dry season. Fort Lauderdale’s wet-dry cycle moves fiber cement more than most people realize. The fix is proper flashing, not endless re-caulking.
See the difference
Before
After
Before
After
Before
AfterReplacement Cost & What’s Included
For a full James Hardie re-side on an existing addition or ADU, Fort Lauderdale homeowners should expect roughly $45,000 to $130,000 depending on square footage, story height, and how much underlying framing needs repair once we open the walls. A smaller single-story ADU on a slab typically runs toward the lower end; a two-story addition with extensive trim, soffit, and rotten sheathing replacement runs toward the top.
| Scope of Work | Typical Installed Price in Fort Lauderdale |
|---|---|
| Full new ADU construction with James Hardie siding and trim | $90,000 – $220,000 |
| Complete re-side of existing addition or ADU | $45,000 – $130,000 |
| Partial siding repair (one elevation, damaged boards removed) | $4,000 – $12,000 |
| Trim and fascia replacement around addition (HardieTrim or AZEK) | $3,500 – $9,500 |
| Soffit and vented eave repair on ADU | $2,800 – $7,000 |
Every quote includes line-item pricing for materials, labor, disposal, and any permit fees. You’ll see the exact Hardie product numbers and quantities we’re ordering, not a vague “siding package.” The written price is what you pay unless you change the scope, and if we find hidden damage behind the siding, we stop and show you before spending another dollar. The work is covered by our 365-Day Done Right Promise: if anything we installed fails within a year of completion, we come back and make it right at no charge.
DIY or Call Us?
You can safely check a few things yourself: walk the addition after a heavy rain and look for water stains at window corners, run your hand along board ends to feel for swelling, and check whether caulk lines at trim joints are intact. None of that requires a ladder taller than a step stool.
What you should not do is pull off HardiePlank yourself. Fiber cement is silica-based, and cutting it releases dust that’s a known respiratory hazard. You need a hard-blade saw, proper dust control, and the right fastening pattern for Fort Lauderdale’s wind-load requirements. More than once we’ve been called out to fix a DIY siding job where a homeowner used standard deck screws on HardiePlank, and the first named storm peeled half the wall off. If your addition is showing signs of failure, call Isaac Pruett and the team at (754) 354-3720. We’ll inspect what you have, tell you what it takes to fix it, and give you a written price before touching a thing.
FAQs
Properly installed James Hardie siding lasts 30 years or more on the substrate, even in Fort Lauderdale’s coastal climate, but the paint finish typically needs recoating every 7 to 10 years. The most common reason we see premature failure on additions and ADUs is installation error, not product defect: missing flashing, wrong fasteners, or zero expansion gaps shorten the effective life to under a decade. Call (754) 354-3720 for a free second-opinion inspection if your Hardie looks older than it is.
In many cases we can replace individual damaged boards and matched trim without re-siding the entire wall, provided the surrounding installation is sound. If the failure is systemic, like no moisture barrier behind the original install or fasteners rusted throughout, a full re-side is the only fix that won’t fail again. We’ll show you photos of what we find before recommending either path.
A typical single-story ADU re-side runs 1 to 2 weeks from tear-off to final caulk and paint prep, including time for Fort Lauderdale permitting and the required inspections. Larger additions with extensive trim, soffit work, or hidden sheathing repair can run 3 to 4 weeks. We’ll give you a schedule with the written estimate so you know which weeks we’re on site and which days the crew won’t be there.
Yes, we stock HardiePlank in the most common Fort Lauderdale exposures and cedar-grain textures, plus HardieTrim and HardieSoffit. For custom ColorPlus finishes or older product lines that Hardie has since revised, we order exact-match boards through our supplier network, and most arrive within a week. We also carry KraftMaid cabinetry, Cambria, and Silestone products when your addition includes an interior build-out, so you’re not juggling multiple contractors.
We tell you what we found, what it takes to fix it, and what it will cost, before we touch a thing. If your James Hardie addition or ADU is showing any of the warning signs above, call (754) 354-3720 to schedule your free estimate. A real person answers every call, day or night, and you’ll know exactly who’s coming to your door before the truck pulls up.
Written by Isaac Pruett, Owner, Mason Remodeling Co Fort Lauderdale at Mason Remodeling Co Fort Lauderdale, serving Fort Lauderdale and nearby areas.
