A $1,500 Facebook Marketplace greenhouse sounds like a steal next to a $5,000 kit. And sometimes it is. But more often, the price you pay on pickup day is the first installment, not the total. Panel yellowing, hidden frame rot, missing hardware, and a transport bill that rivals the purchase price can quietly turn a "deal" into something more expensive than buying new.
This guide walks through the costs second-hand sellers don't list and gives you a checklist to use before handing over cash. By the end you'll know when a used greenhouse is genuinely worth it and when you're being asked to pay someone else to dispose of their problem.
Why polycarbonate panels are the biggest hidden cost
Polycarbonate is the most expensive component on most greenhouse kits and the one that degrades the most predictably. Quality 6mm twin-wall panels are co-extruded with a UV-stabilization layer on the outer face. That layer protects the panel from the sun. It's also surprisingly thin and surprisingly easy to wreck.
Watch for these signs of panel failure:
- Yellowing or hazing along the top surface, especially toward the apex of the roof. This is irreversible UV damage. Light transmission drops from roughly 80% to under 60% in a yellowed panel, and once it starts, it accelerates.
- Brittleness at the edges where panels were cut or trimmed. If you can flick a corner and hear a dry click instead of a flex, the polycarbonate is on its last legs.
- Cloudy interior channels that indicate moisture has wicked in past failed end caps. Once water sits inside the twin-wall channels through a freeze cycle, the panel is done.
- Mismatched panels. A previous owner who replaced one or two panels with single-wall acrylic or generic 4mm is telling you the original spec is no longer intact.
Replacing 6mm twin-wall panels for a 13' x 12' greenhouse runs $900 to $1,400 at North American retail, before shipping. Add custom end caps and aluminum H-profiles to seal them properly and you can clear $1,800. A $1,500 used greenhouse that needs full panel replacement is now a $3,300 project before you've poured a single foundation block.
Frame corrosion is the silent budget killer
Greenhouses live in wet, humid environments. Frames that look fine at first glance often have problems you'll only find with a flashlight and a screwdriver.
On aluminum frames, look for white powdery oxidation around bolt holes and joint connections. A little surface oxidation is cosmetic. Deep pitting at structural connection points is not. The same goes for any sign of galvanic corrosion where steel hardware meets aluminum extrusion — that's the kind of damage that makes a frame wobble in a windstorm.
On galvanized steel frames, look for any orange or red rust bleeding through the zinc coating. Steel frames that have been outdoors for more than 7 to 10 years in Canadian conditions are usually nearing the end of their galvanized service life. Repainting won't save them; the rust will return inside a season.
If the seller can't tell you the brand, year, and original snow and wind ratings, assume the frame is unrated and uninsurable. That matters when a storm rolls through.
The missing-hardware problem nobody warns you about
Greenhouse kits ship with hundreds of small parts: rubber gaskets, aluminum clips, panel retainers, corner brackets, vent arms, hinge pins, threaded inserts. A used greenhouse that was disassembled by the previous owner is almost guaranteed to be missing some of them.
Common casualties:
- Polycarbonate panel clips and H-profile connectors (small, easy to lose, sold by the manufacturer in proprietary sizes)
- Roof vent arms and friction hinges (often left attached and damaged during disassembly)
- Door latches and weather seals
- Corner brackets that hold the wall frames to the roof structure
- Anchor brackets sized for the original foundation
Manufacturer-specific replacement parts can be impossible to source on older or discontinued models. Even when parts are available, you'll often spend 4 to 6 weeks waiting for them to ship from overseas. Generic substitutes rarely fit cleanly and create gaps where water and pests get in.
Before you commit, ask the seller to lay out every bag of hardware on a tarp. Match what they show you to the original assembly manual, page by page. If they don't have the manual, that's a yellow flag on its own.
Transport, disassembly, and reassembly add up fast
Even if the greenhouse itself is structurally sound, getting it home and back upright costs real money.
A 13' x 12' greenhouse weighs roughly 350 to 500 pounds disassembled and occupies a 12' to 14' load bed. A typical Uhaul box truck or trailer rental runs $150 to $300 for a half-day, plus fuel and mileage. If the seller wants you to disassemble it yourself, budget a full Saturday with two people. If you're hiring a handyman, that's another $300 to $500.
Then there's reassembly. A factory kit ships with labeled parts, sequenced packaging, and a step-by-step manual written by someone who built the prototype. A used greenhouse you've taken apart yourself ships in whatever bins you had handy, with mixed hardware and no schematic. Reassembly typically takes 2x to 3x longer than building from a new kit. The Drivhus, for reference, goes up in 6 to 8 hours from boxes with 1 to 3 people. A used greenhouse of the same footprint will take a full weekend at minimum, sometimes longer.
The warranty and support gap
A new kit from a reputable supplier comes with a warranty on the frame (typically 10 to 15 years) and the polycarbonate (typically 7 to 10 years against UV degradation and yellowing). A used greenhouse comes with no warranty, no support, no replacement parts guarantee, and no documentation you can trust.
That matters most when something goes wrong. A roof vent arm snaps. A panel cracks in an ice storm. A door hinge seizes. With a new kit, you call the manufacturer and a part is in the mail. With a used greenhouse, you're on Reddit at midnight trying to identify a generic-looking aluminum extrusion.
We built the Drivhus at $4,999.99 CAD / $3,649.99 USD with free delivery and a warranty precisely because the alternative — patching together a second-hand structure — costs more than people expect when they tally honestly.
When a used greenhouse actually makes sense
None of this means used is always wrong. A used greenhouse is a reasonable buy when:
- The structure is less than 5 years old and you can verify the purchase date with a receipt or invoice
- The original brand and model number are known and the manufacturer still sells replacement parts
- The seller is the original owner, has the manual, and can walk you through every component
- You're paying less than 40% of new retail and you've budgeted at least 25% on top for parts and labor
- You have the tools, time, and patience to do the disassembly and reassembly yourself
If any of those conditions fail, the math tips toward buying new. And in most cases I've seen, at least two of them fail.
Final thoughts
Buying second-hand isn't a savings strategy on its own. It's a savings strategy only when you've inspected the panels, verified the frame, counted the hardware, planned the transport, and accepted that you're trading money for time and risk. Done right, you can save 30% to 50% on a comparable structure. Done wrong, you end up paying full retail in installments — and missing a growing season while you wait for parts.
If the math doesn't work out in your driveway with a calculator and the seller's receipts on the hood of your car, walk away. A purpose-built kit with delivery, documentation, and a warranty is almost always cheaper than the alternative once you account for the costs nobody puts in the listing.