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Therma-Tru Home Additions & ADU: The Houston Owner’s Guide
If you’re planning a home addition or ADU in Houston and want Therma-Tru doors throughout the new space, we install and finish Therma-Tru entry systems, patio doors, and interior doors as part of our remodeling work. A full home addition in Houston typically runs $45,000 – $130,000, while an ADU construction project lands between $90,000 and $220,000 depending on square footage, foundation work, and finish level. Most owners reach out to us when they’re mid-plan and realize their existing door rough openings won’t match standard Therma-Tru sizing, or they’ve bought a Therma-Tru door and need a contractor who actually knows how to install it correctly against Houston’s heat and humidity.
What we see often in Houston: a homeowner orders a Therma-Tru Classic-Craft or Pulse door online, then discovers the rough opening in their 1970s ranch in Meyerland or a bungalow in the Heights is a half-inch too narrow, or the sill pan detail wasn’t accounted for and the first heavy rain finds its way under the threshold. That’s the moment they call us.
Which Therma-Tru Models This Applies To
Therma-Tru builds several distinct door lines, and the installation requirements are not interchangeable. The Classic-Craft series (Mahogany, Oak, Fir collections) uses a fiberglass skin over a polyurethane core and typically needs a specific sill pan system for Houston’s slab-on-grade foundations. The Pulse series is Therma-Tru’s budget-friendly smooth fiberglass line and has different hinge prep specs than the Classic-Craft. Smooth-Star, their mid-tier option, falls between the two in both price and installation complexity.
Here’s the compatibility gotcha most Houston homeowners don’t know: Therma-Tru pre-hung door units come sized for 4-9/16″ or 6-9/16″ wall thickness. Many older Houston homes, especially those built before 1980 in neighborhoods like Timbergrove or Spring Branch, have 2×4 framing with plaster that brings the actual finished wall to nearly 5 inches, meaning the stock jamb width won’t sit flush without shimming and custom extension jambs. We check wall depth before the door gets ordered because returning a special-order Therma-Tru unit is a three-week delay nobody wants. On the OEM versus aftermarket question: for Therma-Tru specifically, we always recommend OEM weatherstripping, sweeps, and threshold components because their profiles don’t match generic replacements cleanly, and a door that seals poorly in Houston is a door that’s costing you money on every summer utility bill.
Styles & brands we work with
Signs Your Therma-Tru Home Additions & ADU Is Failing
- Door sticks or binds at the top corner on humid days. Fiberglass skins expand and contract differently than the wood jamb, and Houston’s July humidity makes an incorrectly shimmed door or a sagging header show up fast. The hinge-side reveal tightens and the door starts dragging.
- Visible daylight or drafts around the weatherstripping. The original Therma-Tru compression gasket compresses permanently after 8 to 12 years of Houston sun and heat cycles. Once it loses its memory, you’re paying for air conditioning that’s leaking out around the door slab.
- Water staining on the interior floor near the threshold. This is almost always a failed sill pan or an improperly flashed rough opening. On Houston slab foundations, there’s no crawl space to catch the water; it runs straight under your threshold and wicks into the flooring.
- The door swings shut on its own or won’t stay open. The slab-on-grade settlement common in Houston neighborhoods like Katy and Cypress shifts the rough opening slightly over time, and a door that was once plumb starts finding its own level.
- Paint or finish delaminating at the bottom rail. Therma-Tru doors hold paint well, but standing water from a poor threshold seal will lift the finish from the bottom edge within three to five years. By the time you see it, the threshold beneath is already compromised.
See the difference
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AfterReplacement Cost & What’s Included
For a full home addition or ADU project in Houston that includes Therma-Tru doors, you’re looking at $45,000 – $130,000 for an addition and $90,000 – $220,000 for a detached ADU. These are the market ranges we quote across Houston, and they include the framing, foundation, roofing, electrical rough-in, drywall, and door installation, with finish work like interior doors, trim, and paint. The range widens based on whether your addition ties into existing rooflines, requires a foundation extension, or needs a kitchenette or bath added.
Our written price before any work starts means you’ll see exactly what each part of the project costs, including the Therma-Tru units themselves and the labor to install them correctly. We don’t charge separately for drop cloths, shoe covers, or daily clean-up; those are part of how we work, not add-ons. Every project carries our 365-Day Done Right Promise, which means if a door doesn’t sit right or a threshold detail fails within a year, we come back and make it right at no charge.
DIY or Call Us?
You can safely check one thing yourself: remove the interior trim on a suspect door and look for shims that have loosened or fallen out over time. You can also check if the weatherstripping feels flattened or brittle by running your hand along the jamb. What you shouldn’t do is pull a pre-hung Therma-Tru unit and try to re-install it, because re-hanging a door against Houston’s slab movement and humidity swings is a two-person job that goes wrong in ways that cost more than the install would have. The same goes for cutting or notching a Therma-Tru slab to fit an out-of-square opening; fiberglass cores don’t trim cleanly, and you’ll destroy the warranty on the door.
If the door sticks, leaks water at the threshold, or won’t seal, call us at (254) 272-5240. We’ll send someone out who has actually installed and adjusted Therma-Tru doors in Houston homes, and we’ll give you a written price before any work begins.
FAQs
A properly installed Therma-Tru fiberglass door should last 25 to 30 years in Houston with routine re-caulking and weatherstripping replacement every 8 to 10 years. The door slab itself rarely fails; it’s the perimeter seal, threshold, and finish that break down first because of Houston’s UV exposure and humidity cycles. Call (254) 272-5240 if you want us to look at your existing door before you replace it.
Yes, if the slab is sound and the issue is the threshold, weatherstripping, hinges, or finish, those are repairable and we do those repairs alongside our remodeling work. If the door slab itself is cracked, delaminated, or warped, replacement is the honest answer. Call (254) 272-5240 for an assessment and we’ll tell you which path makes sense.
A standard single-door Therma-Tru swap in Houston takes one day for removal and install, plus a second visit for final trim and paint if the door needs finishing. A full addition or ADU with multiple Therma-Tru openings takes as long as the overall project runs, and we’ll put that timeline in your written price before any work begins. Call (254) 272-5240 to schedule a walkthrough.
We order each Therma-Tru door to the opening measurements we take on site, which means we don’t stock pre-hung units that might not fit your home’s wall depth. We do keep common weatherstripping profiles, sweeps, and threshold components for Therma-Tru Classic-Craft and Pulse doors on hand, because those are the parts Houston homeowners need most between full door replacements. Call (254) 272-5240 and we’ll tell you exactly what we have and what needs to be ordered.
Written by Graham Stein, Owner, Elmstead Remodeling Houston at Elmstead Remodeling Houston, serving Houston and nearby areas.
