Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Therma-Tru Home Additions & ADU: The Sacramento Owner’s Guide
If you’re planning a home addition or ADU and want Therma-Tru entry doors specified into the project, we handle that from framing to final trim. A finished home addition in Sacramento typically runs $45,000–$130,000, while a detached ADU ranges $90,000–$220,000 depending on size, foundation work, and finish level. Most homeowners reach out to us when they’re replacing a failed door on an existing addition, or when they want a Therma-Tru door integrated into a new build instead of a builder-grade slab that warps within two seasons.
Here’s the situation we see most often: an addition or ADU was built five to ten years ago with a hollow-core exterior door, and Sacramento’s summer heat has done exactly what you’d expect. The door binds at the top corner, the weatherstripping’s compressed flat, and you can see daylight around the latch side. That’s when a Therma-Tru fiberglass door starts looking less like an upgrade and more like the fix you should have made the first time.
Quick Answer: What a Therma-Tru Door on Your Addition or ADU Costs
For a Therma-Tru entry door supplied and installed on a Sacramento addition or ADU, you’re looking at roughly $1,800–$4,500 per door, including the slab, frame, hardware prep, installation, and exterior trim. That’s separate from the addition or ADU construction cost itself. We give you a written price before any work starts, so the door number on day one is the door number on the invoice. No surprise line items when the crew shows up.
If you’re building the addition from scratch, the door is one line item in the $45,000–$130,000 range. If you’re swapping a failed door on an existing structure, it’s a standalone job with its own written quote and the same 365-Day Done Right Promise behind it.
Styles & brands we work with
Which Therma-Tru Models This Applies To
Therma-Tru builds exterior door systems in three broad families that matter for Sacramento additions and ADUs: the Classic-Craft and Fiber-Classic fiberglass lines, the Smooth-Star fiberglass line, and the Pulse and Benchmark steel lines. The compatibility point that catches most homeowners off guard is the rough opening. A Therma-Tru door system is sized as a complete unit, not just a slab, and the rough opening width is typically 2 inches wider than the nominal door size. So a 36-inch door needs a 38-inch rough opening, plus an allowance for shims. If your addition was framed for a generic 36-inch slab door, the opening might be exactly 36.5 inches, and a Therma-Tru system won’t fit without reframing. That’s the kind of thing we catch on the first site visit, not after the door’s been ordered.
OEM versus aftermarket: for the door slab itself, we always install genuine Therma-Tru. For hardware — hinges, weatherstripping, threshold caps, and sweeps — quality aftermarket parts from manufacturers like Endura and Amesbury are functionally equal and often easier to source same-week in Sacramento. For glass inserts and decorative lites, use OEM. The glass-to-frame seal is factory set, and aftermarket glass rarely matches the thermal performance.
Signs Your Therma-Tru Door on an Addition or ADU Is Failing
- Daylight visible around the latch side. The door slab has sagged, or the framing behind it settled. Sacramento’s clay soil expands and contracts through wet winters and dry summers, and additions on perimeter footings move more than the main house. The weatherstripping can’t compensate.
- Water staining at the bottom corners of the rough opening. Typically a failed threshold cap or a corner seal pad that’s degraded from UV exposure. We see this most on west-facing ADU doors in Midtown and Land Park, where afternoon sun beats on the threshold for hours.
- You have to lift the door to get it to latch. Hinge screws have pulled loose from the frame, or the top hinge has wallowed out. This is a symptom we see on older additions where the original door was installed without long screws into the framing.
- The door surface feels spongy or shows hairline cracks at the panel seams. On steel Therma-Tru doors, this means moisture got behind the paint film. On fiberglass, it usually means the door was hit hard enough to delaminate the skin from the core. The core is still solid, but the cosmetic damage compounds.
- Drafts around the perimeter in winter. The original magnetic Q-Lon weatherstripping has compressed past its service life. Sacramento’s temperature swings from 35-degree January mornings to 100-degree August afternoons break down the backing adhesive faster than you’d expect — usually within 6 to 8 years.
See the difference
Before
After
Before
After
Before
AfterReplacement Cost & What’s Included
A Therma-Tru entry door replacement on an existing Sacramento addition or ADU runs $1,800–$4,500 installed, and that range is driven by three things. First, the door line: Smooth-Star sits at the lower end, Classic-Craft with a glass insert and custom finish at the higher end. Second, the rough opening condition: if we have to reframe or repair water-damaged framing, labor goes up, and we show you exactly why before we touch it. Third, hardware: a basic Schlage keyed entry versus a smart lock with a multi-point system changes the number.
Every door quote includes the slab, factory pre-hung frame, hinges, threshold, weatherstripping, interior and exterior trim, hardware prep, installation, and haul-away of the old door. The written price covers the whole thing. If it fails inside a year, we come back and fix it at no charge — that’s the 365-Day Done Right Promise, in writing on every project.
DIY or Call Us?
Some things you can check yourself without risking your door or your fingers. Confirm the rough opening width with a tape measure — that tells you a lot about what door will fit. Check the hinge screws: if they’re 3/4-inch screws, that’s part of your sag problem, and replacing them with 3-inch screws that bite into framing can buy you time. You can clean compressed weatherstripping with mild soap and warm water, which sometimes restores the seal for a season.
What we’d tell you to leave alone: pulling a pre-hung frame out of a load-bearing wall in an addition, resetting a threshold, or hanging a new slab on an old frame that’s out of square by a quarter inch. A door that’s hung wrong will bind, leak air, and void the Therma-Tru warranty. If you’re not sure, call us at (279) 300-1177. We’ll tell you straight whether it’s a repair or a replacement, and the estimate is free either way.
FAQs
A genuine Therma-Tru fiberglass door with proper flashing and a roof overhang above it typically lasts 20 to 30 years in Sacramento’s climate before the slab needs replacement. Steel doors, especially on west-facing exposures without an awning, often show paint failure and edge rust within 8 to 12 years. The hardware and weatherstripping wear out sooner — plan on replacing those every 5 to 7 years. Call (279) 300-1177 and we’ll help you figure out whether you’re looking at a door problem or a hardware problem.
Depends on what failed. Sagging hinges, loose screws, compressed weatherstripping, and worn threshold caps are all repairable on site, usually in one visit. A cracked fiberglass skin, a delaminated panel, or a water-damaged frame generally means replacement — the repair won’t hold up and will cost more than the door is worth within a couple of years. We’ll show you the difference before you spend a dollar.
A straightforward Therma-Tru door replacement — pull the old pre-hung unit, set the new one, trim, caulk, and hardware — takes one full day for most single doors. If the rough opening needs reframing or water damage repair behind the old frame, add a second day. We’ll give you a written schedule before we start, and a defined arrival window so you’re not waiting around all day wondering when the crew shows up.
For the most common Therma-Tru configurations — 36-inch Smooth-Star and Fiber-Classic units in standard heights — we can typically source them same-week through our Sacramento suppliers. Custom sizes, glass inserts, and specific finish packages are factory ordered and usually take 2 to 4 weeks. We also work with KraftMaid cabinetry, Cambria and Silestone countertops, and other trade brands on larger addition and ADU projects, so the door and the rest of the build come from recognized manufacturers with real warranties. Call (279) 300-1177 for a free written estimate, and we’ll give you an exact lead time for your door.
Ready to Get a Written Price?
If you have a Therma-Tru door that’s failing on your Sacramento addition or ADU — or you’re planning a build and want the door specified right the first time — call us at (279) 300-1177. We’ll set up a site visit, take the measurements, and hand you a written price before any work starts. As Trevor Nash says, “Tell me what you want the room to feel like, and I’ll tell you what it actually takes to get there.” That applies to doors too. The price is in writing, the crew shows up in the window we gave you, and the work carries a 365-day promise to make it right.
Written by Trevor Nash, Owner, Penhallow Remodeling Sacramento at Penhallow Remodeling Sacramento, serving Sacramento and nearby areas.
