Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Therma-Tru Home Additions & ADU: The San Francisco Owner’s Guide
Home additions that integrate Therma-Tru doors and ADU construction in San Francisco typically run $53,100 to $153,400, with ADU projects ranging higher when framed as standalone structures. We stock Therma-Tru-compatible entry systems, frame-to-door transitions, and the flashing kits required to tie a new addition into an existing structure without water intrusion. Most owners discover their addition is failing when they see daylight around a door frame, feel a draft near the threshold, or notice the door no longer closes square after the first wet winter.
San Francisco’s climate does specific things to additions. Fog-driven moisture moves through balloon-frame walls in the Outer Sunset differently than dry heat moves through a Richmond District stucco addition. If a Therma-Tru door was installed without proper sill pan flashing or the rough opening wasn’t squared before the frame went in, you’ll see the failure within two to three seasons. That’s not a door problem. That’s an opening problem, and it’s exactly what we address before we ever hang a new slab.
We’re an independent service provider. We’re not affiliated with Therma-Tru. We install their products because they hold up when the rough opening is done right, and we fix installations where the rough opening was never done right to begin with.
Which Therma-Tru Models This Applies To
Therma-Tru builds entry doors across several lines: the Classic-Craft, Fiber-Classic, Smooth-Star, and Pulse series, plus the Benchmark line sold through dealers. For additions and ADUs, we’re usually dealing with the Smooth-Star and Fiber-Classic lines because they’re rated for high-moisture exposure and come in widths that match San Francisco’s older, narrower rough openings.
The compatibility gotcha most owners hit: Therma-Tru slab sizes follow the rough opening, not the old door. A 36-inch door from 1985 measures differently than a modern 36-inch Therma-Tru because the frame profiles changed. You can’t buy a new slab and drop it into an old frame. We measure the rough opening itself, check for out-of-square, and only then specify the door. Trying to match by the old door’s dimensions is how you end up with a 3/4-inch gap at the top.
For OEM versus aftermarket: Therma-Tru’s own weatherstripping, sweeps, and sill caps are engineered for their specific frame channels. Generic aftermarket sweeps are cheap, but they don’t seat correctly in the Therma-Tru kerf, and you’ll still get water under the door. We stock OEM sweeps, sill pans, and hinge shims on the truck. For glass inserts and decorative glass, we order from Therma-Tru because the frame channels are proprietary.
Styles & brands we work with
Signs Your Therma-Tru Home Additions & ADU Is Failing
- Daylight visible around the door frame edges. The framing has shifted or the door was never properly shimmed. In San Francisco’s expansive clay soils and on hillside foundations, movement is common. The fix is re-hanging, not caulking.
- Door binds at the top corner during dry months, closes fine in wet months. Classic thermal expansion mismatch. The addition’s framing absorbs moisture and swells. This is a clearance issue we correct by re-hanging with proper reveal tolerances for our humidity swings.
- Water staining on the interior floor near the threshold. The sill pan was either omitted or installed incorrectly. Once water gets under the sill, it wicks into the subfloor. This is the most common failure we see in fog-exposed additions in the Sunset and Parkside.
- Deadbolt no longer throws fully into the strike plate. The frame settled out of plane. It’s a quick re-shim and re-align, but it’ll keep getting worse until someone actually fixes the frame geometry.
- Noticeable draft or heat loss at the door. The weatherstripping is either worn or the wrong profile for the frame. OEM Therma-Tru weatherstripping lasts about five to seven years in SF’s salt air before it compresses and loses seal.
Replacement Cost & What’s Included
A Therma-Tru door replacement as part of a home addition or ADU project in San Francisco runs roughly $3,540 to $11,800 for the door, frame, hardware, flashing, and labor, depending on size, glass options, and whether we’re correcting an out-of-square opening. A full addition with multiple exterior doors, interior trim, and structural work lands in the $53,100 to $153,400 range. Standalone ADU construction runs $106,200 to $259,600 depending on square footage and site prep.
What drives the range: whether the existing rough opening is square and true, whether the subfloor under the threshold needs repair, and whether you’re adding sidelites or transoms. We give a written price before any work starts, and that number doesn’t move at the door.
Every Therma-Tru installation we do carries the 365-Day Done Right Promise. If the door binds, leaks, or fails within a year, we come back and correct it at no charge. That’s in writing, handed to you at close-out along with the signed scope document.
See the difference
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AfterDIY or Call Us?
You can check a few things yourself: look for visible gaps around the frame, run your hand along the bottom sweep, and check whether the door moves when you pull on the handle with light pressure. These are diagnostic observations. They’ll tell you a problem exists.
What you shouldn’t do is pull the door and try to re-hang it yourself. A Therma-Tru entry door weighs anywhere from 80 to 150 pounds with glass and hardware. Getting the reveal even on all three sides while keeping the weatherseal tight is unforgiving work. We see DIY re-hangs where the door looks fine for six weeks, then the first real storm pushes water under the threshold because the sill pan wasn’t seated correctly. By then the subfloor is wet and the repair cost just doubled.
If the door isn’t sealing, binding, or letting water in, call us at (831) 610-5598. A technician will look at the rough opening, tell you exactly what’s wrong, and give you a written price to fix it. No charge for the estimate.
Key Takeaways
- Therma-Tru doors in additions fail most often from rough opening problems, not door defects.
- Replacement doors must be matched to the rough opening, not the old door’s measurements.
- OEM weatherstripping and sweeps are worth the cost; generic aftermarket parts don’t seat correctly in Therma-Tru channels.
- San Francisco fog and salt air compress weatherseals faster than inland climates. Expect 5-7 years before replacement.
- Every installation carries the 365-Day Done Right Promise in writing.
FAQs
A properly installed Therma-Tru entry door should last 25 to 30 years in San Francisco’s climate, with weatherstripping and sweeps replaced every five to seven years due to salt air and fog-driven moisture. The slab itself rarely fails. The installation and the seals around it fail first. Call (831) 610-5598 for an exact assessment and a written estimate.
Yes, in most cases. If the door slab is intact, we re-hang, re-shim, and realign the frame, replace the OEM weatherstripping and sill pan, and the door operates like new. Replacement only makes sense if the slab is cracked, delaminated, or the original rough opening was framed wrong. Call (831) 610-5598 and we’ll tell you straight which path makes sense.
A straight door replacement takes one day on site. If we’re correcting an out-of-square rough opening or repairing water-damaged subfloor under the threshold, plan for two to three days. We’ll give you a written timeline before work starts, and we stick to it.
We stock OEM Therma-Tru weatherstripping, sweeps, sill pans, and hinge shims on our trucks for same-visit fixes. For slab and frame replacements, we order directly from Therma-Tru’s distribution network, which usually lands in three to five business days in San Francisco. Call (831) 610-5598 and we’ll check stock while you’re on the phone.
Contact Bradford Remodeling Co San Francisco
If your Therma-Tru door isn’t sealing, binding, or keeping water out, call us at (831) 610-5598. Curtis Lane and our crew will inspect the rough opening, give you a straight number, and put the full scope in writing before any tool comes out. Live person answers the phone, 24 hours a day, every day. That’s The Garrison Standard. No surprises at close-out.
Written by Curtis Lane, Owner, Bradford Remodeling Co – San Francisco, CA at Bradford Remodeling Co San Francisco, serving San Francisco and nearby areas.
