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Therma-Tru Home Additions & ADU: The Miami Owner’s Guide
Mason Remodeling Co Miami installs Therma-Tru-compatible door and millwork components as part of home additions and ADU construction across Miami, with full project ranges typically landing between $53,100 and $153,400 depending on scope, foundation work, and finish level. Most homeowners discover they have a Therma-Tru issue when a door stops latching cleanly, a threshold lets water in after a heavy Miami downpour, or a frame has shifted enough that the door scrapes the jamb at the bottom corner. We stock common Therma-Tru replacement thresholds, weatherstripping, and hinge hardware on our trucks, and we can order door slabs, frames, and glass inserts directly through our supplier network, usually within five to seven business days.
Here’s the thing about Therma-Tru products in South Florida: the doors are built well, but Miami’s combination of salt air, relentless humidity, and daily afternoon thunderstorms punishes seals and thresholds faster than almost anywhere else in the country. A door that worked fine in Ohio for fifteen years can show real wear here in six. When you’re planning an addition or ADU, the door package matters more than most people budget for.
Which Therma-Tru Models This Applies To
Therma-Tru builds three main entry door families, and the compatibilities are not interchangeable the way some homeowners assume. The Classic-Craft line uses a fiberglass skin over a solid core, the Fiber-Classic line is a smooth fiberglass face, and the Smooth-Star line is the economical fiberglass option. Hinge mortises, threshold profiles, and weatherstrip channels differ between these families. If you hand us a Smooth-Star hinge and expect it to fit a Classic-Craft slab, it won’t.
For ADU projects specifically, Miami-Dade building code requires impact-rated or high-velocity hurricane zone (HVHZ) rated openings in most cases. Not every Therma-Tru slab meets that standard, so we verify the rating label before ordering. If you’re converting a garage or building a backyard cottage, tell us the door location and we’ll confirm whether you need a Miami-Dade NOA (Notice of Acceptance) on file. Therma-Tru does manufacture impact-rated Classic-Craft slabs, but aftermarket frames often kill the rating if they’re not paired correctly.
We’re an independent service provider, not affiliated with Therma-Tru. What that means for you: we can source OEM Therma-Tru parts, and we’re also honest when a quality aftermarket equivalent makes more sense for your budget. For thresholds and weatherstripping, the aftermarket options from brands like Endura and Pemko are genuinely comparable and often arrive faster. For door slabs and glass, we recommend sticking with OEM to preserve fitment and any remaining manufacturer warranty.
Styles & brands we work with
Signs Your Therma-Tru Home Additions & ADU Is Failing
- Water staining on interior flooring near the threshold. Miami’s rainfall is intense and horizontal during summer storms. A worn thermo-plastic threshold or compressed weatherstrip channels water under the door instead of away from it.
- The door scrapes the jamb on the hinge side or won’t latch without lifting the handle. Humidity cycling causes frames and slabs to move. What starts as a sticky spot in June becomes a door that won’t close by September.
- Visible daylight around the door perimeter when closed. If you can see light, you’re losing conditioned air and inviting insects. Cockroaches love the small gaps at a door’s bottom corners.
- The sweep under the door is cracked, brittle, or partially missing. Sun and salt degrade rubber compounds quickly here. Once the sweep fails, the threshold takes direct water hits and starts corroding underneath.
- Hinges are loose, squealing, or the screw holes have wallowed out. This is usually the first failure point on any exterior door in Miami. The constant open-close cycle plus humidity expansion strips the factory screw holes.
See the difference
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AfterReplacement Cost & What’s Included
For Therma-Tru door replacement as part of a larger home addition or ADU project in Miami, the door package itself typically runs $1,500 to $6,000 installed, depending on slab family, impact rating requirements, and glass options. When you’re building a full addition, your budget range is $53,100 to $153,400, and the door package usually represents about two to four percent of that total. When we replace a standalone Therma-Tru door, labor is $450 to $900, which includes removing the old slab and frame, shimming and leveling the new frame, insulating the rough opening, and re-trimming both sides.
Every quote we write is a fixed, written price before a single tool comes off the truck. No change orders because we “found something unexpected” mid-job. We’re going to find what’s behind that door frame, because Isaac Pruett has torn out enough Miami remodels to expect the unexpected, and we price the fix honestly the first time. Every door installation carries our 365-Day Done Right Promise: if anything we touched fails within a year, we come back and make it right at no cost.
DIY or Call Us?
Replacing a weatherstrip or adjusting a threshold screw height is something a careful homeowner can handle in an afternoon. Replacing a pre-hung exterior door on a Miami ADU is not. Here’s why: when you pull a door frame out of an exterior wall, you’re exposing the rough opening. In older Coconut Grove homes, that opening is rarely square, often has rot from decades of humidity, and sometimes has active termite damage. If you don’t address the underlying condition, your new Therma-Tru door inherits the old problems.
Impact-rated door installation carries a bigger caveat: if the door is rated but installed incorrectly, the rating is void. Insurance companies in Miami-Dade will deny hurricane damage claims on improperly installed openings. We pull the permits, install to code, and pass inspection on every ADU and addition we touch. If you want to check something yourself first, open the door, look at the sweep, look at the threshold cap, and call us at (850) 780-8123 with what you see. Tell us what you need done. Isaac will tell you what it costs and when it’s finished, and he’ll mean both.
FAQs
A properly installed Therma-Tru door in Miami will last 20 plus years structurally, but the weatherstripping, sweep, and threshold typically need replacement every 4 to 7 years due to UV exposure, salt air, and heavy rainfall. If the door is not under a covered entry, expect the finish to show wear sooner and plan for refinishing around year 5.
Yes, in many cases. Loose hinges, failing sweeps, worn thresholds, and chipped fiberglass skins can all be repaired for significantly less than a full replacement. The decision comes down to frame condition. If the frame is square and the water damage is cosmetic, we repair. If the jamb is rotted or the door is out of square in the opening, we replace. Call (850) 780-8123 for a free assessment and we’ll give you the honest answer.
A standard pre-hung Therma-Tru door replacement in a prepared opening takes one day from unboxing to final trim and hardware install. If we’re ordering a custom slab with glass inserts, add five to seven business days for the door to arrive. Impact-rated installations with permit inspection add one to two days for the county inspection schedule.
We carry common Therma-Tru replacement parts on our trucks, including thresholds, weatherstripping, hinge hardware, and sweeps. Door slabs, frames, and glass inserts are ordered per project because sizes and finishes vary too widely to stock every combination. We also stock parts for KraftMaid, Cambria, and Silestone systems for full kitchen and bath additions.
Written by Isaac Pruett, Owner, Mason Remodeling Co Miami at Mason Remodeling Co Miami, serving Miami and nearby areas.
