13 July 2025
While most responsible builders are taking steps towards reducing the huge mass of construction waste going into landfill, one building company has taken a giant leap.
In the two years since starting The Waste Project, Sentinel Homes Waikato has reduced landfill waste by a staggering 80%, and in the process, developed a sustainable new business building cabins and sheds from offcuts and leftovers.
“We took a really hard look at our waste volumes and what it was costing us, and it became obvious we could do a lot better with the resources we were using,” says Sentinel Operations Manager Jono Kraenzlin.
“And rather than take just a few smalls steps, we decided to go all in. We developed an integrated process and took everything in-house. We hired a fulltime Waste Management Manager, bought a truck to service our sites and set up a warehouse as our recycling and repurposing base.
“I think most builders are waiting for an industry-wide solution to the problem, but we didn’t want to wait.”
A solution made simple
“One of the crucial things to make the system work was to get buy-in from our subbies, contractors and suppliers. We updated all our subcontract agreements to include new processes about waste and recycling.
“What really helped to make it appealing to them is that the setup is simple, user-friendly and doesn’t cost them any more time or money. We’ve also talked at length with our suppliers to help where they can. Even small things make a difference. For example, our local ITM supplier stores our pre-nail frames inside so it doesn’t need to be plastic-wrapped for delivery.
“We worked closely with the council when we first developed The Waste Project and have done a number of presentations together at trade events. The response has been really gratifying. A number of local housing companies have approached us asking if we could service their sites.
Could something like this be rolled out as nation-wide service for builders? Could smaller builders band together to so something similar on a co-operative basis?
“I’m sure it could work for other builders and we’re happy to assist in any way we can.”
www.thewasteproject.co.nz
In the two years since starting The Waste Project, Sentinel Homes Waikato has reduced landfill waste by a staggering 80%, and in the process, developed a sustainable new business building cabins and sheds from offcuts and leftovers.
“We took a really hard look at our waste volumes and what it was costing us, and it became obvious we could do a lot better with the resources we were using,” says Sentinel Operations Manager Jono Kraenzlin.
“And rather than take just a few smalls steps, we decided to go all in. We developed an integrated process and took everything in-house. We hired a fulltime Waste Management Manager, bought a truck to service our sites and set up a warehouse as our recycling and repurposing base.
“I think most builders are waiting for an industry-wide solution to the problem, but we didn’t want to wait.”
The leftover materials are used to build tiny homes, cabins and sheds
Turning waste into profit
“When you take into account the cost of skip hire, landfill fees and the value of materials that get dumped, it adds up to many thousands of dollars per house that can be saved,” says Jono.
“We always planned to use a lot of the leftover materials ourselves to build tiny homes, cabins and sheds, and it’s been successful. We’ve sold everything we've made so far.
“The cabins are perfect because they're just a smaller version of what we already build. We can pretty much repurpose all the products we’re already using – timber, plasterboard, insulation, cladding, roofing etc.
“There’s plenty of demand for our cabins as supplementary accommodation. We have a great association with a cabin rental company; they provide the trailer, we build a cabin on it, and they drive it away and rent it out.
“The building itself takes a bit longer because you're using bits and pieces, so the labour content goes up a little bit, but the numbers are working out well. We have licensed builders and some other tradies working pretty much full time at the warehouse. It’s great to provide work for people from something that was just thrown away before.”
“When you take into account the cost of skip hire, landfill fees and the value of materials that get dumped, it adds up to many thousands of dollars per house that can be saved,” says Jono.
“We always planned to use a lot of the leftover materials ourselves to build tiny homes, cabins and sheds, and it’s been successful. We’ve sold everything we've made so far.
“The cabins are perfect because they're just a smaller version of what we already build. We can pretty much repurpose all the products we’re already using – timber, plasterboard, insulation, cladding, roofing etc.
“There’s plenty of demand for our cabins as supplementary accommodation. We have a great association with a cabin rental company; they provide the trailer, we build a cabin on it, and they drive it away and rent it out.
“The building itself takes a bit longer because you're using bits and pieces, so the labour content goes up a little bit, but the numbers are working out well. We have licensed builders and some other tradies working pretty much full time at the warehouse. It’s great to provide work for people from something that was just thrown away before.”
When you take into account the cost of skip hire, landfill fees and the value of materials that get dumped, it adds up to many thousands of dollars per house that can be saved
“One of the crucial things to make the system work was to get buy-in from our subbies, contractors and suppliers. We updated all our subcontract agreements to include new processes about waste and recycling.
“What really helped to make it appealing to them is that the setup is simple, user-friendly and doesn’t cost them any more time or money. We’ve also talked at length with our suppliers to help where they can. Even small things make a difference. For example, our local ITM supplier stores our pre-nail frames inside so it doesn’t need to be plastic-wrapped for delivery.
“We worked closely with the council when we first developed The Waste Project and have done a number of presentations together at trade events. The response has been really gratifying. A number of local housing companies have approached us asking if we could service their sites.
Could something like this be rolled out as nation-wide service for builders? Could smaller builders band together to so something similar on a co-operative basis?
“I’m sure it could work for other builders and we’re happy to assist in any way we can.”
www.thewasteproject.co.nz