This Climate Business: Your next house doesn’t have to be a climate criminal – Mike Hartley (edited excerpts)
Listen to the full episode here.
If you had to choose a sustainability problem that was ripe for fixing, construction wouldn't be a bad bet. Construction and demolition together are usually thought to contribute half of this country's waste to landfill. A report earlier this year for the Ministry of the Environment estimated it at 69%. The good news is that there are people in the industry working to do a better job. One of them is Auckland-based architect Mike Hartley from the firm Lloyd Hartley. Mike reckons sustainability is good design and he's working on a case study project to prove it.
Ross
Let's start with this new project. What is it exactly and how is the design and build process different from any other?
Mike
Shazza's Shack is a minor dwelling project for Sharon Young. The project came into our office via a builder who we've worked with before, who happens to be Sharon's brother, Paul Young. This was a great project for us in that Sharon had a particular kind of sustainability kind of approach that she was interested in. And that gave us a great opportunity to really investigate this. Luckily enough as well, with Paul, he's got that same agenda. So it was pretty cool. We were able to double team on this from two perspectives.
Ross
The builder and the architect getting their heads together on the project early. Is that not typical in the industry?
Mike
No, not particularly. Paul and I have talked a lot about builders being methodology experts. It was really nice to have him in the room and discussing how we might shape the building to make it faster, smarter, just better all round, and being able to use him as a sounding board in that way.
Ross
What specifically is done or will be done differently in Shazza's shack?
Mike
Paul and I identified quite early on that construction waste is a major issue. We thought if there's ways that we can avoid building materials, even making it to site, then we're already reducing that waste. We started really looking at prefabrication and offsite construction. Where we ended up with, in terms of specifics, is replacing standard timber framing with the likes of SIPs – Structurally Insulated Panels. You're getting a double whammy there. One, super high insulation, and two, it comes together all flat-packed, ready to go.
Ross
What's a structurally insulated panel to a layman?
Mike
It’s like a biscuit. A sandwich of high insulation in the middle, and then the strand board on either side. And it comes together like a piece of Lego that's able to slot together and go together in one go. These panels are optimised to standard sheet sizes and they're made in a factory. That factory has the ability to recycle and reuse any waste material on their site rather than on your site, which is a win. We were able to use them as walls and also as roof structure. That was part of it, again, that early conversations with the supplier. They said, if you just make your building a hundred millimetres smaller, we'll be able to get it in one span.
Ross
I understand you now ask for a waste management plan when builders tender?
Mike
Yeah, particularly for our additions and alterations projects, we're hyper aware of the amount of just material that goes into the skip. We're like, how can we start making this part of a conversation? And if we're tendering, let's make it part of that kind of assessment criteria. We know that there's some good work happening with some of the big suppliers and the likes of certified builders.
Ross
What other changes have there been in the way you've designed Shazza’s Shack or in fact the way it's going to be built?
Mike
One was the deck piles. We're using a screw pile system from Stop Digging. Instead of digging a hole, putting timber into it, filling it with concrete, you've basically got a massive screw that you just drill down with a battery-powered drill. Instead of taking three days of preparation, it's literally three hours. That time and the savings involved there are just massive. There's a slab system which is the floor, and it's called a rib raft. We were able to swap out the big pods of polystyrene there with a system from CleverPod, which uses recycled plastic. The small specification decisions have quite a big impact.
Ross
So as it stands today, is Shazza's Shack cheaper or more expensive or the same price as the equivalent more wasteful building?
Mike
At the moment, Paul is pricing this project. We've designed it and the approach that we've taken is a trade-off between labour and upfront cost. Anwhere that we can reduce labour is going to be a win in terms of cost. So that's where prefabrication allows us to do much better. It’s going to be really interesting when Paul finalises his pricing to do a test case.
Ross
Do you think low-waste construction is important enough to home buyers and to developers for architects like yourselves to promote sustainability as part of your brand?
Mike
I think it's a matter of everything everywhere all the time. We need to be hitting all of these things. Fundamentally, good design is going to be sustainable for the purposes of making people feel good about themselves and having connection with others. If we don't do that, we're unsustainable. You can have a really great building that hits all the metrics, hits low waste, but if it's an awful place to be in, what's the point? We've wasted resources.
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