Is there a building materials goldmine in your garage?

With Aotearoa New Zealand’s a serious shortage of building supplies pushing up prices at the hardware store, the scrap and leftover building supplies in your garage could now be worth their weight in gold.

Your old doors, leftover lumber, unwanted taps and jars of nails may not exactly be enough to keep the building industry ticking over, but depending on the condition they’re in, they could be worth selling on Trade Me or Facebook Marketplace to DIYers, renovators and people wanting to complete small projects without having to wait weeks for materials to come in.

In February, Trade Me saw the sale price of building supplies make a 27 per cent jump year-on-year, to an average of $163.67. The number of items listed jumped 7 per cent too.

“There’s no doubt the construction industry is feeling the effects of supply chain shortages, and we’re seeing this reflected in our building and renovation category onsite,” says head of Trade Me Marketplace Lisa Stewart.

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The biggest jump in interest on the site was in the panels and boards category, which had a sales boost of 49 per cent compared with February 2021.

West Auckland sole trader builder Mike Glamuzina sent Stuff a screenshot of a Trade Me auction where bidding for 26 sheets Gib board had topped $5100. The same product is normally listed for sale at Bunnings for $33.82 per sheet before any trade discount is applied, meaning the auction winner paid about six times the usual price. Another Trade Me auction saw bids on a stack of 50 sheets of plasterboard rise above $6000.

Searches for plasterboard trended “more than any other category onsite”, while the most popular searches in the building and renovation category last month were “kitchen”, “cabin”, and “Makita” (the power tool brand).

So, declutterers take heed: If you’ve got those things lurking unloved in your garage, there are Kiwi DIYers out there looking for them.

"Any piece of wood longer than 1.2 metres starts to become useful for a small project,” says Jeremy Gray of Builderscrack.co.nz

Gray has used Trade Me and Marketplace when planning a project that isn’t time sensitive, to see what he might be able to get cheaply or save from going into landfill. He sees Trade Me as the place for “higher ticket items”, while Marketplaces is “more like a garage sale”.

He says items like unused Gib and plywood are also in demand by “tinkerers”, and people looking to convert sheds and garages to living spaces.

Those projects also make leftover insulation such as Pink Batts and Greenstuff valuable online, too. Builders and installers typically dump insulation offcuts, Gray says, but bags of them do come up on Trade Me and Marketplace from time to time.

"It's not a bad approach to buy a couple of bales here and there to get enough to do the job in a week or so, as opposed to having to put an order in and wait a couple of months.”

For items, such as metal pipes, shelving or scraps, scrap metal traders will pay by weight, depending on the metal. They will take anything from air conditioners to coke cans, and engine parts to old windows. One site we checked listed more than 30 items they would take, literally including the kitchen sink – presumably a stainless steel one.

Engine parts, drill bits, and hot water cylinders were requested by the almost all the scrap traders we looked at.

Is there a building materials goldmine in your garage?

"They'll pay a price based on the weight of metals," says Gray. The metals need to be separated, or they'll give you a price for mixed metals that will usually be a little lower.

"They'll usually pay a fixed price for low pressure valves and hot water cylinders because they're mixed and need to be broken down further. But you can take almost anything metal to a scrappy and they'll give you money for it."

Other materials in hot demand were vintage building supplies.

"If you've removed old windows and the timber joinery is rimu that's often quite desirable by timber craftspeople. Any sort of native timbers, if they can be saved, it's good to."

Five valuable items in your garage to look out for:

Old, solid doors

“People use them for all sorts of things, shelving, building tables, or putting doors in sheds," Gray

Kitchen hardware

Hardware such as shelf brackets, rails and door hinges, as well as old kitchen cabinets and cupboards are in demand with DIYers.

“That stuff is hot, because people are always looking to build storage into their sheds."

Unused plasterboard

It’s rare to have unused Gib left over from a professional building project, but you might have some from a home project. "If the Gib's been used, or come out of a reno, then it's pretty much useless."

Screws, nails and other fixings

"There can be some very expensive fixings that can be left over from building projects, especially nail gun nails, that would definitely be worth listing.

"It's easy to get some boxes of nails for [a big project], and have half the box left. That could be enough to complete a smaller project."


“If a shed or garage has been demoed, and the [corrugated iron] roof is in good condition, it’s valuable.”