If your new home build has stalled because your builder can’t access a supply of Gib plasterboard for the wall linings, don’t expect an easy “fix”.

That’s the message Stuff is getting from people in the industry.

Gib is in short supply, but if it’s specified on your consented building plans, you can’t easily swap it for something else.

However, builders working on smaller renovation projects that don’t require building consents have more freedom over material choice, meaning alternative materials could be viable for a renovation.

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Projects that already have a building consent that specifies a particular material, such as Gib, will be expected to use that material, unless you request an amendment. And that may not be straightforward.

Competitors have previously expressed frustration that architects specify ‘Gib’ as if it were a generic term for plasterboard, and council inspectors are inflexible about allowing builders to swap it out.

For a consented plan, any replacement product needs to be pre-approved, Mike Evans, general manager of Consultancy Services for BRANZ explains. “Councils need to be satisfied it meets all the requirements of the building code.”

Evans says there are also products coming in from overseas, some of which meet the building code and some of which don’t. “They don’t always take into account seismic testing. The leaky home history has made councils risk averse, and they will need to be assured of structural integrity and moisture integrity. Products are approved for a particular application, which is another point to consider.”

One industry source who processes building consents says suppliers of substitute products are sometimes unable to supply the level of information required by the building code. “We know there is a lot of frustration out there among builders. There are not the products out there to make good substitutes that don’t cost a lot more money.”

Jeremy Gray of builderscrack.co.nz says builders working on smaller, unconsented projects can often use alternative, imported products: “It depends how extensive the renovation is,” he says. “A lot of materials coming into the country are used for this type of project.”

Gray himself has used a product, simply called ‘plasterboard’, from a local supplier. “We notice people are quite protective of their sources. They are keeping them close to their chest. We also hear that many builders are able to acquire a few sheets of Gib from merchants, but not enough for a new home build.”

Either way, he has this advice for homeowners and tradies: “The earlier a homeowner can plan their project, the better. And we like to set expectations – the larger your project, the longer you will have to wait.”

Specifying other materials at the design stage is another way around the supply problem (bearing in mind supply should increase once the new Winstone Wallboards factory in Tauranga comes on stream next May).

Only around 5% or so of the plasterboard market is not in the hands of Fletcher Building (the manufacturer of Gib plasterboard through its subsidiary Winstone Wallboards), but alternative approved suppliers include Elephant Plasterboard, which imports product from Thailand; ProRoc, which imports a small amount of product from French multinational Saint-Gobain and sells through Bunnings; Youngman Supply Group; and a handful of small Chinese importers.

But cost will be a factor when it comes to other materials, says Gray: “As soon as you step away from Gib, your costs go up. They may go up 10% to 20% with the next cheapest option, then continue up from there.”

BRANZ has had a number of enquiries from companies with alternative products looking to enter the market, and have appraisals underway, but the process of testing and approval can take as long as six months. “We do things as quickly as we can, but most of the conversations we are having are in the early stages, so (getting the products to market) could be some time away.”

Structural plywood is an option to consider, especially if you are still at the design stage. But it is considerably more expensive than Gib, and a totally different look – it is usually stained, so the grain is exposed. Plywood lining that is not structural is less expensive, but won’t provide bracing.

Gray says he is a “massive fan” of natural cladding materials, such as timber and earth renders. “But they are markedly more expensive and not used in mass-produced homes.” He mentions shiplap and tongue-and-groove timbers as possible options.

This strong fibre-cement sheeting is commonly used for wet areas, and also would be a more expensive option for an entire house.

“Some of these boards require a lot of prep work if they are to be laid over a big area, and probably need to be papered before painting to get the required finish,” Gray says.

MDF is not recommended as a replacement for wall linings. It’s heavy, prone to mould when damp, and will not give the same finish. It expands and contracts, so gaps between boards cannot be plastered, resulting in an unfinished look. Gray says it’s a rough finish, and more suited to sheds.

Stuff has talked to a homeowner looking to use the new recycled Saveboard for a renovation – they hope to avoid the Gib shortages, and like the idea of a recycled material.

Over the past four years, founder Paul Charteris has converted 4000 tonnes of waste per year from landfill into sustainable building materials.

The downside is that the product is slightly more expensive than plasterboard due to the longer time it takes to produce. The firm says it takes around 50% longer to install than standard plasterboard, but that time can be made up by not needing to block out between studs for cabinets, towel rails and similar.

Saveboard also has a more textural finish that may need skimming, depending on the look required.

Bigger builders, like Signature Homes which currently has 530 home builds underway, don’t seem to be looking for substitutes in the short term. CEO Paul Bull says the company pre-orders Gib through merchants, “usually four-to-five months ahead” and puts supplier agreements in place.

“We will redirect trades on the same house,” when Gib is not immediately available, he says. “They may start preparing the driveway or the landscaping.

“But there is no doubt, the shortage is increasing build times, and that’s a bit of a train crash (for the industry), because of the inflationary pressures that come into play.

“While plasterboard prices have been reasonably stable, the prices of other materials (going into a build) are going up over those three-to-four months.”