Therma-Tru Home Additions & ADU Nationwide

Therma-Tru Home Additions & ADU: The Miami Owner’s Guide

We install Therma-Tru entry systems and compatible door packages into home additions and ADUs across Miami, with typical installed pricing from $53,100 to $153,400 for full additions and $106,200 to $259,600 for detached ADUs. Therma-Tru fiberglass entry doors are the most common spec we see on Miami-Dade addition projects, particularly in Coral Gables and Pinecrest, where the FBC-rated impact versions are code-required. Most owners discover a mismatch or failure when their addition’s rough opening doesn’t align with the Therma-Tru pre-hung unit they ordered, or when the impact-rated sidelite seal begins weeping after a season of tropical moisture cycling.

Call (786) 321-4970

Which Therma-Tru Models This Applies To

We work with Therma-Tru’s Classic-Craft, Smooth-Star, and Fiber-Classic collections most often in Miami, plus the Impact-rated series required by Florida Building Code in HVHZ zones. The critical identifier is the AAMA/NAMI certification label on the hinge edge, which lists the DP rating (Design Pressure) - Miami-Dade requires DP-50 or higher for exterior doors on new additions, and many owners source a DP-35 unit online that won’t pass inspection.

To identify your exact part needs: measure the rough opening width, height, and wall thickness (4-9/16″ is standard 2×4 framing with drywall; 6-9/16″ for 2×6), then cross-reference the Therma-Tru spec sheet for jamb width compatibility. The Classic-Craft Mahogany collection uses a proprietary composite jamb that cannot be substituted with standard pine; Smooth-Star accepts standard wood or composite jambs. We stock both OEM jambs and Endura FrameSaver equivalents on our trucks - the FrameSaver carries a lifetime warranty against rot, which matters in Miami’s humidity where we’ve seen standard pine jambs fail in 18 months.

Rowan Construction Group Miami is an independent contractor, not affiliated with Therma-Tru.

Signs Your Therma-Tru Home Additions & ADU Is Failing

• Daylight visible around the door perimeter when closed. The composite door slab has likely shifted on its hinges due to Miami’s thermal expansion cycles, or the weatherstrip has compressed past recovery. This gap bypasses the impact rating and admits driving rain during summer storms.
• Water staining on the interior jamb or floor after heavy rain. The sill pan or end dam flashing was omitted or improperly lapped during installation, a common issue we find in owner-managed ADU builds in Wynwood and Little Haiti where crews skipped the secondary seal.
• Door drags or binds at the top corner. The frame has racked due to inadequate shimming at the hinge side, or the header has settled. In Miami’s coral rock substrate, foundation micro-movement transmits to the addition’s door frame differently than on the main structure.
• Fogging between sidelite or transom glass panes. The insulated glass unit seal has failed; on impact-rated Therma-Tru units, the replacement IGU must carry the same missile-impact certification, not just any dual-pane unit.
• Soft or discolored jamb bottom, particularly on the hinge side. Capillary water wicking from the sill into the jamb end grain. In Miami’s climate, this accelerates to structural rot in 8-14 months if the jamb lacks end-seal treatment or a composite shoe.

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Replacement Cost & What’s Included

What drives the range: wall condition (stucco tear-out and re-wrap adds labor), whether the opening needs header modification for impact rating, and if the existing floor elevation requires a threshold ramp for ADA compliance on rental ADUs. Under Clause 1 of The Haven Standard, you receive a written line-item price before any work starts - no change proceeds without a signed change order. Every installation includes our 365-Day Done Right Promise and a documented photo record of the rough opening condition, flashing sequence, and final door operation.

DIY or Call Us?

What you can safely check: verify the DP rating on your existing door label against your permit documents; confirm the rough opening dimensions with a tape measure; inspect the sill pan from the exterior for visible gaps or missing end dams. These checks require no tools beyond a flashlight and tell you whether you’re dealing with a specification error or a physical failure.

Where DIY goes wrong: impact-rated door installation in Miami-Dade requires TAS-201/202/203 or ASTM E1886/E1996 testing documentation, proper shimming at all hinge locations to maintain the design pressure rating, and sill pan integration with the weather-resistive barrier that most owner-installers lap incorrectly. A failed inspection costs 2-3 weeks and a re-inspection fee. We’ve re-hung six Therma-Tru units in the past year that passed the slam test but failed the water infiltration test due to sealant omission at the head flashing.

Call (786) 321-4970 to schedule your free estimate. We’ll measure the opening, verify the code requirement for your specific Miami address, and deliver a written price with no obligation.

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