Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Therma-Tru Home Additions & ADU: The Miami Owner’s Guide
Adding square footage to a Miami home with Therma-Tru doors and windows integrated into the build typically runs $53,100 to $153,400 for a full addition, and $106,200 to $259,600 for a detached ADU. We stock and install Therma-Tru-compatible entry systems, patio doors, and sidelights for additions across Miami-Dade, and we can usually match your existing Therma-Tru profiles within a few days. Most owners call us when a builder or handyman warned them that “you can’t match that door” or when a failed sill pan has already started showing water damage at the base of an existing Therma-Tru unit that’s now part of a larger addition plan.
Which Therma-Tru Models This Applies To
Therma-Tru builds doors and door systems across several series lines that show up constantly in Miami additions: the Classic-Craft, Fiber-Classic, Smooth-Star, and Pulse series. Each has different slab thicknesses, frame depths, and sill profiles, and mixing them is where we see most mismatched installations. The Classic-Craft and Fiber-Classic lines use a 6-panel or smooth fiberglass slab with a rot-resistant frame, and they’re what most Coral Gables and Pinecrest homes already have. Smooth-Star is the budget-friendly line, and Pulse is the newer composite with a deeper embossed grain. The compatibility gotcha: Therma-Tru frame depths vary by series and by when the unit was manufactured. A 2008 Smooth-Star frame is not the same depth as a 2023 Pulse frame, and forcing a new slab into an old frame creates an air gap that kills your A/C efficiency and invites Miami humidity into the wall cavity. If you’re adding onto a home with existing Therma-Tru units, we match by the hinge stamping and the sticker on the hinge-side jamb; if the sticker’s gone, we measure the slab thickness and the sill profile. For OEM parts we order direct from Therma-Tru distribution; for aftermarket thresholds and weatherstripping we carry equivalents that match OEM tolerances.
Styles & brands we work with
Signs Your Therma-Tru Home Additions & ADU Is Failing
- Water staining at the bottom corners of the door – The sill pan underneath a Therma-Tru door is PVC or composite, but Miami’s summer downpours find any gap between the pan and the rough opening. The stain means water is already wicking into the subfloor.
- The door rubs at the top or latch side – South Florida’s humidity swells the frame and shifts the rough opening. A door that closed fine in January and rubs in August is a frame or substrate problem, not a hinge adjustment problem.
- Condensation between the glass panes in a sidelight or door lite – The insulated glass seal has failed. Once that seal goes, the argon escapes and the unit fogs permanently. You replace the lite, not the whole door.
- Fiberglass skin delaminating or bubbling near the bottom rail – That’s the classic Therma-Tru failure in Miami: constant splashback at the sill causes the skin to separate from the core. Cosmetic at first, structural if left for another rainy season.
- The door won’t latch without lifting or pulling – The adjustable sill has settled or the frame has racked. In an addition context, this often means the rough opening was framed too tight and the door was forced in.
See the difference
Before
After
Before
After
Before
AfterReplacement Cost & What’s Included
Installed Therma-Tru entry and patio door work inside a Miami addition or ADU project runs on a sliding scale depending on what we’re doing:
- Full Therma-Tru entry door replacement with sidelight, installed: $2,360 to $7,670
- Slab-only replacement (reusing existing frame): $1,180 to $3,540
- Lite or glass replacement in an existing Therma-Tru unit: $470 to $1,770
- Sill pan replacement with rot repair at the threshold: $500 to $1,950
- Complete home addition including Therma-Tru doors, windows, and trim: $53,100 to $153,400
- ADU construction with Therma-Tru entry and patio packages: $106,200 to $259,600
The range moves based on series (Pulse runs higher than Smooth-Star), whether the rough opening needs reframing, and whether we’re replacing one unit or multiple openings as part of a larger build. Every quote from Sawyer Remodel Miami includes the part, labor, disposal, and a written price before any work starts. Our installs carry the 365-Day Done Right Promise: if it’s not done right, we make it right, in writing.
DIY or Call Us?
You can safely inspect your Therma-Tru unit yourself: look at the bottom corners for staining, check the weatherstripping, look for fogged glass. That costs you nothing and helps you describe the problem accurately when you call. What you shouldn’t do is pull the door or the frame yourself. Therma-Tru doors are heavy – a Classic-Craft slab with a full lite can run 60-plus pounds – and the frame shims, sill pan, and flashing all have to be right or the door leaks within one Miami rainy season. We’ve fixed enough DIY extractions in Kendall and the Roads to know that the repair costs more than the original install would have. Call (850) 801-8046 and we’ll come look at it.
FAQs
A properly installed Therma-Tru entry door lasts 20 to 30 years in South Florida, but the sill pan and weatherstripping typically need attention every 7 to 10 years because of our heat, humidity, and afternoon downpours. The fiberglass slab itself won’t rot, but the parts around it will. Call (850) 801-8046 for an inspection if your door is over a decade old.
Yes, in most cases we can replace a fogged lite, swap the sill, or re-shim a racked frame without buying a new slab. If the fiberglass skin is delaminating or the core is waterlogged, replacement makes more financial sense than repair. We’ll tell you which is cheaper before you spend a dollar.
A straightforward slab swap or lite replacement takes 2 to 3 hours on site. A full frame replacement with reframing and new flashing runs half a day to a full day. As part of a larger addition or ADU build, the door package gets scheduled in sequence with the rest of the project. Either way, you get a written time commitment before work starts.
We stock common Therma-Tru wear items on the truck – thresholds, weatherstripping, hinge sets, and standard lite sizes. Series-specific slabs and specialty sidelights we order from Therma-Tru distribution, which typically takes 3 to 5 business days in the Miami market. If it’s an emergency opening, we can temporarily secure the existing door while the right part comes in.
Written by Luca Romano, Owner & Lead Contractor, Sawyer Remodel Miami at Sawyer Remodel Miami, serving Miami and nearby areas.
