The refurbishment of the Hayman Kronfeld Buildings (a reversion to their original names − they were known as Old Sofrana House and the Barrington Building) brings the buildings to 5 Star Green Star standards. Britomart Group’s development director Campbell Williamson oversaw every stage of this intricate project. 

MELINDA WILLIAMS When did you decide to target a 5 Green Star rating for the refurbishment of the Hayman Kronfeld Building?

CAMPBELL WILLIAMSON We held back on going for the Green Star rating until we were some way into the refurbishment. I wanted to be sure we knew Green Star from beginning to end before making a commitment to it. We were in the process of completing The Hotel Britomart, which already had a 5 Green Star Design rating, but at that time the Build ratings were done separately as the follow-on verification of the design through to built. We were already six months into the Hayman Kronfeld project before we received final confirmation of the 5 Green Star Build for the hotel. It was from there that we felt confident with the whole process for achieving a 5 Green Star rating for this project. We're committed to building in an environmentally friendly way anyway and Green Star is very much integrated with everything else, so as soon as we made that decision, we had everybody sitting around the table, ready to go. There was some minor tweaking to the design, although we were generally well prepared.

MW What were some of the ways existing materials were put to new uses within this building? 

CW One feature that is really nice is the brick floor in the Galway Street lobby. During the build we had to put a few holes through walls to make openings as we joined the Hayman and Kronfeld buildings together. So what we did was recycle those bricks so they now form the floor of the lobby, which is really cool. We used as much as the original wood flooring as we could, as we usually do. There was also a lot of lovely kauri timber wall panelling which we decided to use for cladding on all of the bathroom blocks. We didn't have quite enough of it to clad all the blocks, but we were able to get some more kauri timber from a recycler to make up the difference. We always look as much as possible at what we can recycle back into the building and how we might challenge ourselves to think differently about what we could reuse that we might otherwise overlook. 

MW What’s another example of re-use in the project? 

CW There was an old safe room, completely in the wrong place and structurally impossible to retain. It was dangerous. We carefully dismantled the brick construction and cleaned them all up, and a lot of them now form the lobby floor. We then had this massive steel safe door with the old-school large keyhole lock, chunky hinges and riveted steel plate. And we thought, 'Well, where can we put that?' We had an old doorway in the new lobby area that we had filled in with brick, and it looked a bit odd with its concrete lintel seemingly doing nothing. But as it turned out, the odd door head and the safe door matched up perfectly. So we pulled off one layer of brick and recessed the safe door underneath the door head. And it looks very cool. When people are standing in the lobby waiting for their cup of coffee, they might spend some time puzzling over it, and a few may recognise it for what it was.

MW Has bringing a heritage character building up to a 5 Star Green Star standard of heating, ventilation, air tightness, daylight, acoustic comfort and so on been more challenging than designing a 5 Green Star building from scratch, as was done with The Hotel Britomart? 

CW We always want buildings to perform to modern standards of good structure, strength and safety and to be warm and healthy. So, yes, it can be a challenge working out how to preserve as much as possible alongside what it takes to bring the building up to the premium office standards we’re aiming to achieve. For instance, it would be very easy to take the original windows out and put in modern, perfectly waterproof, soundproof, temperature-proof windows with solar shading. But then you lose the beautiful character. So we're always working out where the line is drawn between what we reuse and what we put in brand new.

We take care to remind ourselves to stand back and check we’re not going too far to try to preserve something from the original building, to the point that the preservation becomes environmentally unsustainable. There are situations where we'd need to do so much to adapt or accommodate an existing element that putting in a brand-new element is definitely the lower-impact way to go. Heritage is not a line that we hold at all costs, even though we never drop our focus on this – we always question our decisions and choices as to whether we have the overall sustainability balance right. Another comparison of new build versus refurbishment is that when you design from scratch, you can design so everything is perfectly efficient and compatible with everything else. You can create long, beautiful beam spans with as few columns and walls interrupting them as possible. You have a lot more opportunity make the most of what is called the usable space.

With a heritage building, there are all those walls and columns already in place that you have to live with and work around. But what's kind of fun is that those oddities actually give the spaces a richness that you would never design into a new building. And when it's all fitted out, people walk in and go, 'I love this'. They will put desks up against a column or make it into a breakout space. That awkward stub of a wall with old door openings in it adds beauty and interest and enrichment. So refurbishing rather than designing new adds complexity, but in a way, it makes it more interesting and fun because we are forever working with a puzzle that has many solutions and the trick is finding the best solution.

MW One aspect of heritage buildings that can make them challenging as office spaces is that they can be quite dark, in contrast to light-filled modern glass-wall offices. How was daylighting increased in this refurbishment?

CW That is very true. The dominance of the dark heavy timbers in combination with the relatively small window openings can feel gloomy. A really important goal we set ourselves with the design here was that the core area and stairs and lift areas had to lighten the building up. They were a fundamental part of the structural upgrade, although we wanted them to celebrate the heritage elements of the building in terms of its brick and steel and timber, and also be something that looked stunning from the ground floor entrance lobby all the way up through to the top of the building.

We’ve put a skylight at the top with fine steel window joinery, so now we have lots of light pouring down through the steel-and-glass lift shafts and the lift cars themselves are also glass. The natural light makes it all the way down to the ground floor lobby, which gives a really nice experience, along with the natural light coming through the original heritage windows into the stairs as well. We hope all that light will encourage people to not only want to use the lifts, but the stairs as well, given that it's only a four-storey building. The entrance lobby is going to be amazing – it’s not massive in comparison to some modern office buildings but it has a very high ceiling and there’s a heritage grandeur about it. The filtered light that comes down will give us something special, celebrating the heritage fabric of the building. It's magic.

Then in the office floors, we selected a light fitting that is quite sleek in profile, with the light globes recessed so that they don’t catch the eye, giving the impression that the light is pouring in naturally from the heritage windows and the exterior views beyond. The fitting also lights up, highlighting the kauri floor joists above the light fittings, in stunning balance to the kauri board flooring underfoot. 

MW Were there any particular lessons learned from The Hotel Britomart Green Star build process that you were able to take into this project? 

CW There were a lot. We've the same main contractor with many of the same subcontractors – structural, acoustic, fire and services engineers. We've also got the same Green Star consultants. That was about 75 percent of the key people who needed to understand Green Star and what we were trying to achieve in really fine detail. So we just went straight to it, with the perfect head start.

MW Have Green Star standards changed a lot since the time the East (Westpac and EY) Building, which has a 4 Star Green Star Design rating, was constructed?

CW I wasn’t involved in the East Building project, but I know there's been a lot of maturing of the way we look at things since then, not just us but across the whole construction industry. Green Star was quite new to the industry [in 2011 when the East Building was finished], so there was a lot in the design of the building that was theoretical or aspirational. That is not at all a criticism: quite the contrary, you've got to start somewhere.

It turned out to be really hard to follow through on some of the construction of the original design because the industry was not yet up to speed. But just the fact of designing to Green Star standards was the beginning of getting people familiar with what we needed to do and how to do it. By the time we got to building The Hotel Britomart, the industry was very much focused on delivering the aspiration. Now with Hayman Kronfeld, there's no separation between Design and Built ratings like there was previously, it’s all done together. And it's a really good thing. With time, everybody gets more sophisticated, more aware and more able to do better.

MW Within this 5 Star Green Star space, individual companies who lease the spaces can also fit out the spaces to Green Star standards and apply for an Interior Green Star rating, can't they? 

CW Yes. One of the Green Star rating points that we chose to pursue for this refurbishment was that we would include a commitment from our tenants to fit out their spaces in a way that didn’t compromise the ability of the building to perform to the standards we have set and, further, that their fit-outs would use our Base Build to stretch their own sustainability goals. We've set up technological systems in the building to monitor water usage and power usage and air conditioning systems and air quality and so on.

Our tenants have committed to work with us to ensure that we collect all the data from both our organisations so that together we can fine-tune the office spaces to minimise energy usage and negative impacts on the environment, because we will be seeking a NABERSNZ energy efficiency rating for the building. At least one of the tenants is even taking that a step further and going for the Better Buildings Challenge standards.

NEXT / Refurbishing heritage buildings often uncovers old stories too. Read the story of the original owner of the Kronfeld Building, as told by his great-great-granddaughter, Emily Parr.