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Therma-Tru Home Additions & ADU: The Houston Owner’s Guide
We install Therma-Tru entry doors, patio doors, and trim systems as part of home additions and ADU builds across Houston, with full-project pricing typically running $45,000 – $130,000 for a home addition and $90,000 – $220,000 for a freestanding ADU. We’re an independent contractor, not affiliated with Therma-Tru, and we carry their product line because the frames, thresholds, and weatherstripping hold up to Houston humidity better than most factory doors we’ve pulled out of old additions. If you’re planning an addition or ADU and want Therma-Tru doors specified from the start, call (940) 289-7658 for a free estimate.
Most owners call us after the fact: they had an addition built years ago, the original contractor used builder-grade doors, and now the frame has shifted, the threshold is rotted at the corners, and the sweep doesn’t seal. Or they’re building an ADU and the plans call for a front entry that meets floodplain elevation requirements, which changes the door rough-in. Either way, the question is the same: what does it cost to do this right, and will it stay right. That’s what we answer below.
Key takeaways:
- Therma-Tru doors in additions and ADUs run $1,200 – $4,500 installed per unit depending on size, glass package, and whether the rough opening needs reframing.
- Houston’s humidity and shifting clay soil mean the door frame is usually the first thing to fail, not the slab itself.
- Every project gets a written price before we start, and the full-year 365-Day Done Right Promise covers the work after close.
Which Therma-Tru Models This Applies To
Therma-Tru builds three door lines that show up in Houston additions and ADUs. The Classic-Craft series is their fiberglass entry that looks like stained wood and comes in standard 6’8″, 7’0″, and 8’0″ heights. The Smooth-Star line is the lower-profile fiberglass door, common on side entries and ADU rear doors. The Pulse series is the modern square-edge door you see on contemporary additions in Montrose and the Heights. Each line uses different hinge prep, brickmould profiles, and weatherseal channels, so the parts are not freely interchangeable across series.
The gotcha we see most: a homeowner orders a replacement threshold or sweep for a Classic-Craft door, not realizing the 7’0″ and 8’0″ units use a wider profile than the 6’8″ version. If the door tag is gone, measure the slab width and the gap between the side jambs. Our techs do this on site before quoting any part, because ordering the wrong sweep means a seal that drags or gaps at the corners, and in Houston a gapped corner means mold on the jamb within two seasons.
For OEM versus aftermarket: Therma-Tru’s own weatherseal kits are engineered to their channel dimensions, and that matters. We’ve tried aftermarket sweeps on Classic-Craft doors and about half of them fit loose in the kerf. The OEM parts cost more, but when we’re standing behind the work for a full year under the 365-Day Done Right Promise, we’d rather install the part we know seats correctly the first time.
Styles & brands we work with
Signs Your Therma-Tru Home Additions & ADU Is Failing
- Daylight under the door sweep. The vinyl sweep has compressed or torn. This is the most common failure on Houston additions because the door gets used constantly and the threshold takes direct sun on west-facing walls. A worn sweep means conditioned air leaks out and humidity pushes in.
- Corner rot or cracking at the threshold. Thresholds on older additions often sat directly on a concrete slab with no sill pan underneath. Water wicks up at the ends, the wood or composite rots, and the threshold drops. That drop is what makes the door drag or hang up at the strike side.
- The door binds at the top corner. Houston’s clay soil expands and contracts with moisture, and slab foundations move. When an addition’s slab edge settles even a quarter inch, the rough opening racks, and the door starts binding. The fix is shimming the jamb and rehanging the frame, not planing the door.
- Flaking finish on a fiberglass slab. Classic-Craft doors have a factory finish that fails early if the door faces heavy afternoon sun and the finish wasn’t maintained. Flaking itself is cosmetic, but it exposes the fiberglass to UV, and the next stage is surface cracking that lets water into the skin.
- Condensation or mildew on the interior jamb. This tells you the seal has failed and humid air is condensing on the cool interior surface. In an ADU with a kitchenette, that moisture feeds mold quickly. The fix is usually a new weatherseal assembly and, if the jamb is soft, a partial frame rebuild.
See the difference
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After
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AfterReplacement Cost & What’s Included
Installing a complete Therma-Tru entry system in a Houston addition or ADU runs $1,200 – $4,500 per door, installed. The spread depends on the series, the glass package, whether we’re reframing the rough opening, and whether the sill needs elevation work for floodplain compliance. A simple slab swap on an existing square frame might come in under $1,000 if the jamb is sound; a full frame tear-out with a new rot-proof sill pan, brickmould, and casing will push toward the top of the range.
Here’s the line-item picture:
- Therma-Tru Classic-Craft or Smooth-Star slab: $600 – $1,800 depending on glass and size
- New frame, jamb, and brickmould: $300 – $700 if the old frame is compromised
- Threshold, sweep, and weatherseal kit (OEM): $150 – $400
- Labor for full install and seal: $400 – $1,000 depending on demo and reframing
Every quote is a written line-item price before work starts. No numbers that move at the door. The 365-Day Done Right Promise covers the install and the parts we supply for a full year: if that door binds, leaks, or the seal fails inside twelve months, we come back and correct it at no charge.
DIY or Call Us?
Replacing a door sweep is a 15-minute job if you have the right part and a hacksaw. Checking whether your threshold is level with a 4-foot bubble level is something any homeowner can do. But pulling a Therma-Tru frame to replace a sill or rebuilding a rotted jamb is structural work: the door is an exterior wall penetration, and if the rough opening isn’t squared and the sill pan isn’t sloped correctly, you’ll be back in the same spot in two Houston summers. There’s no high-tension component here like a garage spring, so this isn’t a danger warning; it’s a cost-of-being-wrong warning. Call (940) 289-7658 and we’ll give you a straight number.
FAQs
A properly installed Classic-Craft or Smooth-Star door should give you 20 – 30 years in Houston, with the weatherseal components needing replacement every 5 – 7 years. The frame life depends almost entirely on the original installation; if the sill wasn’t flashed well on the original addition, the frame can fail in under 10 years. Call (940) 289-7658 and we’ll tell you what you’re actually looking at, not what a brochure says.
Yes, and most of the time repair is the right call. We replace sweeps, thresholds, weatherseal kits, and can rehang a binding slab without swapping the door itself. If the slab skin is cracked or the frame is rotted through, replacement costs less than chasing it. The estimate is free and we’ll show you the condition in writing before you decide.
A single door swap with a sound frame takes half a day. A full frame tear-out and rebuild takes one day for most additions, sometimes two if we’re dealing with a brickmould tie-in on brick veneer. We schedule the work, we show up when we say we will, and we leave the site swept and the old door hauled off.
We keep OEM sweeps, thresholds, and weatherseal kits for Classic-Craft and Smooth-Star doors on the truck for jobs we’ve quoted, and we order slabs directly from Therma-Tru’s distribution network as soon as the written scope is approved. Same-day availability depends on the part, but we’ll tell you the lead time at the estimate, and that lead time holds. Call (940) 289-7658 if you need a straight answer today.
Straight scope, straight number, that’s the whole conversation. If you’re adding on or building an ADU in Houston and want Therma-Tru doors done by a crew that puts every price and every guarantee in writing before a tool comes out, call (940) 289-7658. Curtis Lane gives you the number up front and stands behind the work for a year.
Written by Curtis Lane, Owner, Bradford Remodeling Co Houston at Bradford Remodeling Co Houston, serving Houston and nearby areas.
