Plant Prefab Junior ADU Conversion: The San Antonio Owner’s Guide
If you own a Plant Prefab unit in San Antonio and the junior ADU conversion components are wearing out, we stock the replacement parts and can usually get them installed within a week of your first call. A full junior ADU conversion refresh (kitchenette, bath hookups, separation wall hardware) typically runs $8,500 to $22,000 installed depending on what’s failing. Most owners notice the problem when the conversion wall stops latching cleanly or the plumbing stub-outs start seeping at the connection points.
Plant Prefab builds their junior units with specific wall-channel tolerances, and San Antonio’s clay-heavy soil shifting plus summer humidity cycles put real stress on those connections. We’re an independent contractor, not a Plant Prefab dealer, which means we match parts honestly rather than pushing a factory-only markup.
Key takeaways:
- Junior ADU conversion parts for Plant Prefab units are modular but not universal; wall-channel width matters
- Installed cost including labor lands between $8,500 and $22,000 in San Antonio
- Most failures start at plumbing stub-outs and door hardware, not the frame
- We provide a written price before any work begins, no exceptions
Which Plant Prefab Models This Applies To
Plant Prefab’s junior units ship along two main chassis lines: the standard 10-foot-wide module and the narrower 8-foot-6 “slim” series. The conversion kit from factory to JADU (junior accessory dwelling unit) includes the separating wall, the efficiency kitchenette rough-in, and the bath vent stack. The gotcha most owners hit: the wall channel on the slim series is 3/4 inch narrower than the standard module, and a lot of generic aftermarket kits don’t account for that. Measure the exposed channel before you order anything.
On OEM versus aftermarket for Plant Prefab specifically: the factory hardware is fine, but the door hinges and latch assemblies they spec are contractor-grade and we replace them with heavier stainless versions when we see repeat failures. The stub-out fittings are proprietary spacing, so we keep both OEM and matched aftermarket on hand. For Abodu, Cover, and Dvele units we do the same pattern matching, but this page is about your Plant Prefab junior conversion.
Signs Your Plant Prefab Junior ADU Conversion Is Failing
- Separation wall won’t latch or drifts after latching: The wall channel has come out of level. San Antonio’s expansive clay moves enough during wet-dry cycles to shift the lower track by a quarter inch, which is all it takes to make the latch miss. The fix is re-shimming the track, not forcing the door.
- Kitchenette sink drains slow or gurgles: The factory stub-out uses a shallow P-trap that clogs faster than a standard residential trap. Mineral buildup from San Antonio’s hard water makes it worse within two to three years.
- Water staining at the conversion wall baseboard: The stub-out gaskets dry out in our summer heat. Once they crack, every sink use weeps a little water behind the wall. You won’t see it until the baseboard swells.
- Vent stack rattles when the bath fan runs: The factory bracket is a friction fit. Thermal expansion from attic heat in July loosens it until the stack knocks against the framing. It’s simple to fix but annoying to ignore.
- Electrical outlets on the conversion wall go dead: The pre-wired harness running through the wall channel can pinch when the wall is opened and closed repeatedly. We’ve repaired this on units in Alamo Heights and near Woodlawn Lake within the first five years of service.
Replacement Cost & What’s Included
In San Antonio, you’ll pay $8,500 to $12,000 for a partial conversion refresh (latch hardware, channel re-shim, stub-out gasket replacement, vent bracket). A full rebuild including new kitchenette rough-in, new separation wall hardware throughout, and re-plumbing the drain stack runs $15,000 to $22,000. What moves the number: whether the stub-outs need to be re-cut, whether your wall channel is standard or slim width, and whether we’re pulling new wire through the harness or repairing a pinch point.
| Repair Scope | Parts | Labor | Typical Total |
|---|---|---|---|
| Latch & channel re-shim | $400 – $700 | $350 – $550 | $750 – $1,250 |
| Stub-out gasket replacement | $150 – $300 | $400 – $600 | $550 – $900 |
| Drain stack re-plumb | $600 – $1,100 | $800 – $1,400 | $1,400 – $2,500 |
| Full conversion refresh | $4,500 – $7,000 | $4,000 – $8,000 | $8,500 – $15,000 |
Every quote is written, line-item priced, and handed to you before work starts. The 365-Day Done Right Promise covers our labor and the parts we install. If something fails within a year, we come back and fix it. Free second visit if a covered repair fails again.
DIY or Call Us?
You can safely check a few things yourself: whether the wall channel has visible debris, whether the outlet is tripped at the breaker, whether the sink trap is just clogged. If the latch is misaligned by more than a hair, leave it. Forcing a separation wall back into a shifted track bends the channel, and now you’re paying for a track replacement on top of the shim job.
The plumbing stub-outs and the electrical harness are where DIY goes sideways. The stub-out connection is under line pressure, and a bad gasket swap means water inside your wall. The harness carries 120V through a moving joint. That’s not a YouTube fix. Call us at (430) 258-2928 and we’ll diagnose it straight, put the number on paper, and get it done right.
FAQs
Most factory conversion hardware lasts 7 to 10 years in San Antonio’s climate, but the stub-out gaskets and latch springs typically need attention around year 4 or 5. The heat and hard water are the main culprits. Call (430) 258-2928 if yours is acting up; we’ll tell you honestly whether it’s a repair or a replacement.
Latch assemblies and channel shims can often be repaired in place, but stub-out gaskets and vent brackets are replace-on-fail items. Repairs make sense when the underlying track is still straight. We’ll give you the repair-or-replace call with a written price either way.
A partial refresh takes one day on site. A full conversion rebuild runs two to three days, mostly because we wait for the plumber’s putty and sealant to cure before re-pressurizing lines. You’ll have a live schedule and photo updates throughout.
Yes. We keep standard and slim-series wall channels, stainless latch kits, stub-out gasket sets, and heavier-gauge vent brackets in our San Antonio inventory. If we don’t have your exact part, we can usually source it within three business days and install by week’s end.
Call Benson ADU San Antonio
If your Plant Prefab junior conversion is failing, don’t guess. Troy Eastman and our team will diagnose it, price it, and put the whole thing in writing before any work starts. No verbal roulette. No surprise invoice at the door. Call (430) 258-2928 to schedule your free estimate. The number goes on paper first. Everything else follows from there.
Written by Troy Eastman, Owner & Builder, Benson ADU San Antonio at Benson ADU San Antonio, serving San Antonio and nearby areas.
