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Boxabl Windows & Doors: The San Antonio Owner’s Guide
If your Boxabl Casita’s window or door is binding, leaking, or no longer sealing against Texas heat and humidity, we can match it, price it, and install it. Installed replacement typically runs $450 – $1,400 per window and $800 – $2,800 per door in San Antonio, depending on size, glass spec, and whether we’re reusing the existing rough opening or reframing. Most owners discover the problem the way you just did: a window that suddenly won’t close flush, a door that drags on the threshold after a hard rain, or condensation between panes where there used to be clear glass.
We’re Mason Remodeling Co San Antonio, an independent San Antonio contractor. We are not affiliated with Boxabl, but we’ve worked on enough of these units across Bexar County to know exactly what you’re looking at. Isaac Pruett has been building and repairing homes in this city for years, and he’d be the first to tell you: Boxabl windows and doors are good units, but the Texas sun and our clay-heavy soil do things to them that a factory in Las Vegas never planned for.
Key Takeaways
- Boxabl Casita windows are standard 36″ × 36″ and 36″ × 48″ vinyl-frame units with Low-E glass; doors are 36″ × 80″ with a fiberglass slab
- Window replacement in San Antonio runs $450 – $1,400 installed; doors run $800 – $2,800 installed
- We stock common Boxabl-compatible glass packs and door hardware on our trucks, which means most swaps happen in one visit
- You don’t need to buy OEM parts from Boxabl; quality aftermarket units with matching specs install cleanly and often carry a better glass warranty
- Call (254) 269-5071 and we’ll give you a written price before any work starts
Which Boxabl Models This Applies To
The current Boxabl product line is primarily the Casita, a 20′ × 19′ accessory dwelling unit that ships with two windows and one entry door. That’s the unit we see most often in San Antonio backyards, whether it’s serving as a granny flat in Alamo Heights, a home office in Stone Oak, or a rental unit near the Medical Center. If you have a Casita, you have a 36″ × 36″ window on one wall, a 36″ × 48″ on another, and a 36″ × 80″ entry door with a fiberglass slab and standard 4-9/16″ jamb depth.
Here’s the compatibility gotcha most owners don’t learn until a replacement is already ordered: Boxabl uses modular-construction window bucks, meaning the rough opening is framed for a specific flange profile. A standard big-box vinyl window will not seat correctly without modification. We’ve measured these openings on at least a dozen Casitas across San Antonio, and the consistent spec is a new-construction flange, not a retrofit flange. Order the retrofit style and you’ll be shimming more than you’d like, which eventually translates to air leaks and water intrusion. We always measure the opening and the existing frame before we order anything.
As for OEM versus aftermarket: Boxabl will sell you replacement glass packs and door slabs, but the lead time can stretch to weeks, and you’ll pay their parts margin on top of your installer’s labor. We routinely install name-brand aftermarket units with identical glass coatings, the same U-factor rating, and better local warranty support than you’ll get going direct. We also keep compatible hardware on the truck: threshold caps, sweep seals, and replacement hinges that match the Casita’s door prep.
Styles & brands we work with
Signs Your Boxabl Windows & Doors Is Failing
These are the symptoms we hear most often on San Antonio service calls, and in the order homeowners usually notice them:
- The door won’t latch without lifting the handle. San Antonio sits on expansive clay, and Boxabl units settle just like stick-built homes do. When the unit shifts even a quarter inch, the strike plate and latch misalign. It’s usually fixable with a re-shim and re-hang, but if the slab itself has warped from heat, the door needs replacement.
- Condensation or fogging between the glass panes. This means the insulated glazing unit (IGU) has failed. The seal between panes has cracked, Argon gas has escaped, and now you’re trapping moisture inside the window. On a Casita, this typically shows up first on the west-facing elevation, where afternoon heat in San Antonio is brutal.
- The window binds when you crank it or slide it. The vinyl frame has likely distorted from thermal cycling, or the operator hardware has stripped. On Boxabl units, the sliding track can also collect sandy grit from our dry spells; if it’s been grinding, the track is probably scored and the window needs new rollers or a full sash replacement.
- Water staining on the interior drywall below a window or door. This is the one to take seriously. A failed weather seal or a badly seated flange lets rainwater wick into the wall cavity. By the time you see a stain, it’s been happening for a while. We open the wall, inspecting framing, replacing any rotted sections, and then install the new unit with fresh flashing.
- You can feel a draft or see daylight around the door perimeter. The threshold seal has compressed, the door sweep is gone, or the jamb has separated from the rough opening. Daylight around the slab is a loss of airtightness and an entry point for insects, and in a unit as small as a Casita, even a small air leak makes the HVAC work measurably harder.
See the difference
Before
After
Before
After
Before
AfterReplacement Cost & What’s Included
Here’s what San Antonio homeowners can expect to pay, installed, based on the service calls we’ve run across the city:
| Part | Installed Price Range | Typical Job Time |
|---|---|---|
| 36″ × 36″ Boxabl-compatible window | $450 – $850 | 2 – 3 hours per window |
| 36″ × 48″ Boxabl-compatible window | $550 – $1,050 | 2 – 3 hours per window |
| 36″ × 80″ fiberglass entry door | $800 – $1,900 | 4 – 6 hours per door |
| Door slab only (reuse existing frame) | $600 – $1,200 | 2 – 3 hours |
| Full door with new jamb, threshold, hardware, and flashing | $1,800 – $2,800 | 1 day |
That range is honest, and we’ll tell you exactly where your job falls before we order anything. The biggest cost drivers are glass thickness, frame color (white matches the stock Casita; any custom hue adds material cost and lead time), and whether we discover hidden damage once the old unit is out. If the wall cavity is rotted or the rough opening has shifted, the framing repair is extra, and we’ll quote it line-item before touching it. Every Boxabl window and door install is covered by a written guarantee for 365 days from the completion date. If the work fails within that year, we come back and make it right at no cost.
DIY or Call Us?
Windows and doors on a Boxabl are tricky because the unit isn’t sitting on a conventional foundation, and the rough openings are less forgiving than you’d find in a site-built home. You can safely do the diagnostics yourself: run your hand around the interior trim, check for damp drywall, and look for visible gaps in the exterior caulking around the flange. But once you start pulling the frame or prying off the nailing fin, you risk cracking the exterior composite skin, and that’s a much bigger repair than the window itself.
Door replacement is even less of a DIY candidate. Resetting a pre-hung door on a shifting modular unit takes shims, patience, and enough experience to know when the slab is fighting you because the unit itself moved. We also handle disposal of the old sash and glazing, which is not a fun trip to a Bexar County transfer station. If you want the job done in a day and sealed correctly the first time, call (254) 269-5071. We’ll give you a written price before we start.
FAQs
Expect about 10 to 15 years from the original vinyl windows and fiberglass door slab in San Antonio’s climate. The IGU seals typically fail first, usually in the 8- to 12-year range, because our diurnal temperature swings stress the sealant. Aftermarket units with cardinal or equivalent Low-E glass often carry a 20-year glass warranty, which outlasts the original spec. If yours are fogging at any age, call (254) 269-5071 and we’ll tell you whether a glass pack swap or a full-window replacement makes sense for your Casita.
We can, in specific cases. If the IGU alone has failed, we can often swap the glass pack and keep your existing frame, which saves money and avoids cutting into the exterior skin. If the door is misaligned, a re-hang solves it. But if the vinyl frame is warped, the track is scored, or the slab has absorbed enough moisture to swell, replacement is the better investment. We’ll tell you honestly which one is which. Call (254) 269-5071 for an assessment with no guesswork.
A single window swap is a half-day job; a door with a new jamb typically takes a full day. Two windows and a door on the same Casita can be completed in two working days, including caulking, flashing, and interior trim touch-up. We’re not going to camp in your backyard; our San Antonio crews run lean and get the job done. We’ll give you a schedule in writing before we start. Call (254) 269-5071 to set a date.
We keep common 36″ × 36″ and 36″ × 48″ glass packs, replacement door slabs, threshold caps, and hardware in our San Antonio stock, so many Casita jobs go from first call to finished install within the same week. If your unit needs a custom color or a non-standard size, we order it and have it in hand within five to ten business days, depending on the supplier. Either way, you get a written lead time and a fixed price before we start. Call (254) 269-5071 to check stock for your unit today.
If your Boxabl windows or doors are failing, don’t wait for a leak to get worse. We serve the entire San Antonio area, from Helotes to Converse, and we’ll come to you, measure what you have, and give you a written price before any work starts. Know who’s coming, know what it costs, know it’s covered, that’s the whole job before the job starts.
Our crews also stock and service windows and doors compatible with KraftMaid, Cambria, and Silestone product lines, so if your remodel has mixed-brand components, we can match what’s already there. Call (254) 269-5071 to schedule your free estimate.
Written by Isaac Pruett, Owner, Mason Remodeling Co San Antonio at Mason Remodeling Co San Antonio, serving San Antonio and nearby areas.
