Mass Timber Office Design

The Evolution of Mass Timber Office Design

Foreword by Ian Thompson, Editor

Our hosts WoodSolutions Australia take us on a journey exploring the design and construction of two unique mass timber buildings in Sydney, the International House and Daramu House.

This video is not just a showcase of these two remarkable structures. It’s also a deep dive into the evolution of their designs, the challenges faced during construction, and the valuable lessons learned along the way.

What’s really fascinating is seeing how the team took their experiences from building the International House and applied them to the Daramu House. They weren’t content with just replicating what they had done before. Instead, they pushed the boundaries, resulting in some groundbreaking changes in their approach to structural grids and floor systems.

Another interesting aspect is their approach to nature. Rather than overwhelming nature with their architecture, they aimed to invite it in, something many designers miss. This focus on creating an architecture reflective of nature resulted in the use of timber as a primary building material and the incorporation of green spaces, including a meadow roof on Daramu House.

Plus, the video highlights the inherent flexibility and adaptability of timber buildings. It’s enlightening to see how these structures can be designed to accommodate changes and modifications over time.

So, whether you’re an architect, a builder, or just someone interested in sustainable construction and design, this video has something for you. It’s an insightful look into the potential of timber as a building material and how it can be used to create structures that are not only visually stunning and sustainable but also flexible and adaptable to future needs.

The Evolution of Mass Timber Office Design

Mass Timber Office Design

Video Transcript

We’ll get underway. Andrew has only given us 40 minutes. I keep telling him we need four hours, but we’ll try and cram it all in.

So these are the two buildings we’re going to be presenting on. On the left in the distance is International House, and on the right, closer to the foreground, Darrenville House. You can see together they sort of form this new streetscape to Sussex Street. Barangaroo is a new urban renewal area that has been a poor facility since Sydney was formed.

So we’re really going to be looking at what inspired International House to start with, that was delivered first, and then the evolution of the design and the lessons learned that we were able to scaffold off for the second building, Daramu.

And then we’ll leave it up to you which, if there’s a winner or not, but there’s essentially those pros and cons with with both. So it’s a really interesting study they’re so similar in such similar locations, to look at the difference between the two and what evolved as we’re going across the land.

I would like to pay our respects to Aboriginal and Torres Strait Islanders across our land it sees. So today we’ve got four parts: one is the inspiration for the buildings, essentially why, why do they look as they are, why they build out of timber; the architectural expression and how that has evolved between the two; the interior character sort of may look very similar between the two.

But fundamental differences as a result of the structural change between them; and then the construction lessons learned, what lessons were learned from one and two, and then what are we going to apply to number three.

So the inspiration, um, first of all we started off with the master plan prepared by RSHP, which in a very simple statement sort of relied on these radial pedestrian paths leading through from the CBD, which is the top of the page, through the precinct to the Sydney Harbour, which is at the bottom of the page.

The original master plan contemplated three buildings seven stories high along Sussex Street, and then three towers behind them, much taller, along the center of the side. So the street buildings were to give that straight edge and as a transition up to the taller towers behind.

One of the first moves was to combine those two southern buildings into one to make them more economically viable, to still maintain the intent of the radial pedestrian footpaths. And then what resulted was a forecourt space at the entry point here, the closest point to the CBD, like a landing area, generosity at the time.

So that really formed this family of buildings: the three towers at the back and then the two sisters at the front. So shared kind of DNA but very distinct personality between the three towers and between the two buildings.

So there’s a really nice parallel between Barangaroo itself, the development over the years, over the last 200 years, how the site has evolved and how these buildings develop. So I’m just quickly going to run over some of that. This is the foreshore line 100 years ago. You can see this western edge of the CBD was the port facility for the city, and it was populated by finger wars and piers projecting out into the harbour.

So that the ships pulled alongside and offloaded to the side. And 100 years ago the go-to structural material for structures like this was timber: solid, large profile, honestly detailed, robustly designed solid timber structures.

Fast forward to 50 years ago and the foreshore heart line had a completely different aesthetic. It progressed to a container ship wharf, but as you can see, the whole site was covered with concrete. So no sense of natural topography, landscape, materiality, no sort of sense of its original land. All of that was obliterated to be overwhelmed by this concrete structure. And that again, that’s typically what happened 50 years ago.

Continue Reading

Fast forward to today and this is what the foreshore looks like. It’s returned to some of that natural edge using some of those natural materials and stone descending down into the water, natural landscape topography returning to the site, in an appreciation that nature makes this city much more livable and enjoyable to sort of live with nature, amongst nature, rather than just obliterating it and leaving it for the bush, and in the cities where cities in the bush there’s a divide. No, we should be combining the two to make a beautiful livable city.

So strong parallel with that with these two buildings. We wanted to develop an architecture which was more reflective of nature rather than overwhelming nature and muscling it out. We wanted to invite nature into the building. So that was a big driver for the character of these two projects.

And internally they were both delivered pre-COVID, but aspirations are really sort of highlighted with COVID, but we want workplaces which are focused on the health and the well-being of all the users, to provide spaces which make you feel good, make you feel relaxed and engaged, and making a sense that you are within nature, surrounded by nature, rather than artificial materials of concrete and plasterboard.

And then the advantages in building with mass timber: what are the benefits of this off-site prefabrication, delivery to site and this rapid construction that we’ll be focusing on in that last section of the presentation?

So the architectural expression, this is the ground floor plan. You can see those sort of two buildings that did with the response to the pedestrian network, they ended up kind of being three on the ground plane anyway with the pedestrian links. You can see the ground floor, which is predominantly retail, sort of bends and warps and falls to encourage that movement down from the street and into the into the pedestrian network of Barangaroo.

On the bottom side, on the west is the laneway, more like an 8th Street. And then on the east is this culinard that leads all the way through linking both buildings that collide again, acts into two directions: moving east to west, it’s a threshold into the precinct, it’s like an announcement that you’re entering on into this site. And then from north to south, it’s really acts like a formal sort of urban device to sort of move pedestrians to the left up to Headland Park and to the right into the city.

The two foyers are quite different. With the extra length of Dharamu, we’re able to provide a double loaded foyer activating both the culinard and the laneway. An International House on the right here, it was single loaded. So in elevation from the street, the master plan had arranged a seven story building along there again as this transition up to the towers.

We break that up further into a five on two massing. So the five at the top is essentially the more private space, it’s the office space raised up on the colonnade, and then the lower two stories, it’s really the public domain associated with the pedestrian movement through visitors and users over the site who aren’t necessarily going to these buildings but entering into the site.

On the left, International House had a very formal two-story height colonnade. On the right, you can just see over here the start of the next building coming which is a Renzo Piano apartment building which had a single story colonnade. So Daramu was the transition between those two. It’s got moments of two-story, essentially where you’re moving through and into the building. So at each end it’s borrowed one of the International House Y-shaped columns at each end, and then in the center here is the entry into the building.

So the materiality changes as well between the five and two. Here is the lower two: this is looking down the colonnade, where the materiality is reflecting back to those original wharf structures of Barangaroo Foreshore: solid timber hardwood elements, again very honest, very robust. These straps are about 450 square and they’re supporting the undercarriage of that five story above.

You can see in the soffit line above that’s the the CLT and the glue laminated timber of the first office floor sort of performing this double height space. And then this steel knuckle here is the sort of the connection between this Australian recycled hardwood timbers and the blonde European spruce engineered timbers above. There’s quite a clear distinction between the two.

The hardwood timbers were procured from Australian Architectural Hardwood up in Kentucky. They did a magnificent job. And the photo on the left is to demonstrate that they are authentic solid timber elements supporting this seven-story building. It’s not as we’ve become accustomed in the last 50 years of the veneer or a cladding or a cover to something that’s doing the work. This this timber column is doing all the work.

And on the right is the other elements in this two-story public domain space which is the soffits of the single-story colonnades, the sun shading devices on the upper levels or all of the family of recyclable hardwood. And then these are these are areas where you can move through the building. You can just see the harbor in the distance.

So the pip is a very permeable pair of buildings. And above that, really clear expression of the structure. This is the northern end of Daramu. Again it’s it’s a very different urban context so we change the architecture to respond to that context. This is the only street in Barangaroo South that leads off Sussex street and into the precinct. 

So we wanted to morph the northern end to turn pedestrians around and into this. Into the precinct as well as vehicular traffic.  So you can see down the bottom here, this is where one of those double height public domain spaces is.  So the pedestrians are led around the building and you know fluids sort of sweep down to the harbour.

Whereas this north eastern edge of the building still reinforces the boundary edge of the site. The right hand wrapping um affords a terrace up here on the roof which ha sthe views along the street to the harbour water.  And at the lower level it sort of leads pedestrians around and down this back lane which is the heat stream the city. 

Again you can see that sort of marriage of the lower stories of the richer hardwood red deeper colors and then the blonder timber. Both buildings deployed external sunshade devices depending on the orientation and the overshadowing is either single double or triple layered sunshade devices which allowed the glass to be as clear as possible – low iron glass, so you can look through and see that direct expression of engineered timber behind, brought right up close to the facade.

So it was the hero of the building, not the facade doing something funky. As you can see here, this is the double height lobby into Daramu House, the hardwood timbers wrapping around and ends leading you into the into that lobby, and the lateral bracing of the five stories above located directly above the lobby – essentially an architectural expression into here, big arrows down to the to the lobby.

But also what it afforded us in structural terms is that the pair of K-braces, five stories high, acted as a beautiful big five-story truss which took the load across to these two columns down in the colonnade column in Colorado there, which is an 18 meter wide span of the building.

Again we’re looking at where this timber could evolve from International House. We wouldn’t have had the confidence to do this, in four years ago, but we had the confidence and the knowledge of the structure that we could form this truss. And you can notice the column is deleted below the center of the truss, giving that 18 meter wide span, that generosity of opening at the entry point. And again, sort of wrapping that timber into the into the lobby, making it very present onto the street.

At night these two buildings have a completely different character. Most CBD towers at night, if the lights are left on, give this sort of cool grey light. In contrast, International House and Daramu glow – kind of a wooden jewelry box almost on the street, really contributing again that sense of nature and warmth and humanity back to the streets.

Rooftop again, another huge evolution between the two. Both roofs are constructed from CLT, the structure of CLT and glue lam. Yet with International House, on top of that is insulation, membrane, and then a concrete slab to give it that hard shell on the roof, which works well, but again it’s the one one of the last remnants of reinforced concrete on the on the job.

So um, the thought process was to replace that with something completely opposite again, connected to nature, following on the principles of the project really which is to embrace nature rather than obliterate it.

So wouldn’t it be fantastic if the roof was a meadow? And what what are the challenges with that and what are the advantages with that? Obviously advantage of looking down onto the roof is this beautiful green lush space, brings biodiversity to the site – birds, bees, snails onto the site. And it also helps to cool the photovoltaics.

There’s a bunch of PhD students up on the two roofs at the moment again, asking this question of evolution: what’s the difference between the two roofs – a concrete roof? How do the PVs perform in a green roof? What’s the temperature difference on the roof between the two? What’s the savings in water and energy by having a green roof to sort of build up real-life data?

And again, it’s not laboratory data, it’s realized data of these two roofs. And having the two sisters with completely different sort of characters, it’s a very straightforward exercise. The green roof is sort of much more lush than this now with all the rain and sun that we’ve been having lately. It’s a really incredible roof.

So that leads to the interior character. Um, both buildings sort of celebrate timber on the inside, not relying on any kind of cladding linings, finishes, ceilings to give the character to the space. It’s the structure.

So even on that structure, both buildings adopted a very different structural approach to the two. In size terms, International House on the right is about 8,000 square meters, and on the left, Daramu is 50% larger at about 12,000 square meters. Yet you can see the number of structural timber elements are pretty much the same, despite that 50% larger floor plate.

So the fundamental difference then comes to the the grid used. So International House, again we we were exploring world-first opportunities for um, what a structural grid should be for an office building. And there were very few examples around the world that we could sort of reflect on at this time. Tarmedia was one, but very few others to sort of look at and visit and go on, “What are the pros and cons of that?”

So it’s very much a research phase here to get to the 9×6. And then we have the decision with Dharamu: do we just make these sisters twins? Did we just keep them identical? We know how to do 9×6, do we just do 9×6 again? But the team was challenged with “Well, why don’t we keep on expanding, keep on developing, keep on innovating and expand that grid to a nine by nine point five meter grid?”

So 50% larger again, first of its world. What does that mean? We couldn’t just look at examples and sort of use those, we sort of had to go back to the drawing board essentially, Jeremy.

And sort of reflect on how that could be achieved. Yeah, Jay, just to add to that, the um, it’s great to have a building side by side um and be able to learn from one and then replicating to another. But equally, challenge yourself not just to replicate, rather than to go out and and be adventurous and see how far you can push this.

Bearing in mind, you know, CLT glue lam structures of this size are still relatively novel, and um, we’re learning how to do things better and better every day. The learning curve still continues to be quite steep. Um, you’ve got two bookends here on a commercial office – it’s a 9×6 at nine nine. Um, from a timber perspective, and and i think this is the largest grid of its nature in the world that we’re we’re aware of.

And I’d really welcome anyone telling us they’ve done anything bigger, because we haven’t seen anything bigger. Not that it’s a competition, um, but it shows that the um, the big grids um, if a tenant or a developer likes to have a larger format um, then they they can do that. And yeah, we used a little bit more timber um per square meter on the larger grids than we do on the smaller grids.

It would be fair to say that the International Health Sydney is is a slightly more efficient perspective building from a total usage of timber. However, we’re probably using timber in a more economic perspective on Dharamu House, because we’re using more glue lam, less CLT. So the ratios of CLT to Glulam are quite different between the two products, and we’ll come more into that in a moment as slides progress. Sorry, back to you Jonathan.

Yeah, thanks. So it wasn’t just a matter of expanding everything and sort of putting it on the photocopier and stretching this grid. It really required a whole rethink of the structural approach.

So International House on the right deployed the primary beams across the building, so the shorter length of the building, which resulted in the CLT floor panels just spanning the six metres from primary good to primary grid. But nine meters was just pushing the CLT too far structurally. So it was decided to rotate the whole structure and the whole – all of the primary beams 90 degrees to run the length of the building north-south.

So advantages and disadvantages are certainly advantages in the services layout that we’ll come to a bit later, in the reticulation of services along the building. But what that generated was a rethink of cold floor structure. So like I said, on International House on the right, the CLT slabs span the intervene, so it’s really a two layer system – Glulam beams, CLT sitting on top, simply supported, quite straightforward.

Daramu House, um, with the nine meters, introduced the need for glue lam secondary beams across the space, across those nine meters, which then relaxed the the need for the CLT to space. It’s now only doing three meters from secondary being the secondary beam. So the CLT got much thinner with the introduction of the glue lam.

And that’s the change in proportion that Jeremy was just talking about. But now it’s a three-layer system. We’ve got primary beams, secondary beams, CLT slabs, so we’ve just introduced a whole heap of new members potentially, which wouldn’t be advantageous because more members, more time, more crane lifts.

So Daramu House, for the floor system, looked at a cassette system. So again, advantages and disadvantages – it’s not just a no-brainer, just go with this. But you can see them on the left there, essentially a C-shaped cassette – secondary, half of a secondary beam on each side, and the CLT’s slab joining the two to deliver a three meter wide and a half meter long cassette. So once again, that introduced a single list in the crane rather than link lifting the separate beams in the slabs.

We’re back to fewer elements to lift up, the increased volume of timber the Jeremy described, you’d have to assess that and then increase the glulam to clt. But it also obviously introduces this additional off-site process to join those three pieces together. 

If you ship them like that, there’s a lot of air that you’re shipping.  You can see in the middle here. There’s a big body in the void space.  Potentially you could fill up with other beams and columns.  Again make a very efficient packing but you wouldn’t want to sort of transport air like that for too far. So that sort of then triggered this process where it was delivered to an offsite factory and luckily Lenny’s had those to. Then be assembled into these three members brought back to site. 

And then what’s on that journey. Yeah look, i think from a lessons learned perspective and we do come to the lessons learned further on as well. But just looking at this photo while it’s topic alum the complication of doing a cassette system and having that secondary phase of fabrication.

If you think the glue laminate clt invariably doesn’t come from the same factory and at some point together it has to come together before you lift it into site.  But I guess it doesn’t have to but for us, site time is much more expensive than factory time. You know when you’re basically assessing your program on you on how quickly you can lift those elements into its final resting place you recognize that the fewer number of elements, the better it is. 

Lifting one large element versus three small element, sum the the rate per element is aboutthe same. The size of the element is doesn’t really make too much of an impact I think this was the right solution for Darren House on a 9×9 grid. I would definitely do the pre-fabrication before it came to site. I think the quality control is better, and I think it frees the delivery team to do what they’re good at – lifting pieces in large format into their resting place.

Jonathan noted you need then to have a place nearby where you can pre-assemble this stuff. Theoretically, you could pre-assemble it down here, but in a CBD, that’s a real challenge. But there’s no reason why you couldn’t secure a warehouse within four or five, even 20 or 30 kilometers away, to pre-assemble all that stuff before it comes to site.

The square meter each of those panels were in the end identical between the two buildings. International House was 12 meters by 14.95m, and Daramu House nine by three, so about 27 square meters per floor panel per lift, even though they’re completely different profiles and formats.

So that leads to a different, with those different systems, a very different internal character, which is the topic of this section. So internally, looking across the space in there, again the K braces form part of the character of the space, part of the geometry and interest in the space. But if you look at the ceiling software, it has this very strong beam and then bolts in between the beams, and then beam and bolt on a three meter center.

So advantages with that is, again like I said, the services reticulation. Some of them are up inside the vault running east-west, and then the ones running north-south just slide in underneath the secondary beams to be above 2.7 ceiling and not have to engage with the timber. They can just slide underneath, so reduces the amount of coordination and provides additional flexibility in the future.

Looking down the length of the space, again this is Daramu One, and this is probably a 90 meter view to the other end of the building. You can see that this strong sort of central spine of primary beams through the middle here and against the glazing on the left. But the lowest height then is the services running through from front to back.

If we contrast that with the interior of International House, which is running across the space, the predominant feature as you look down the length of the spaces, the timber beams. Again, you’ve got this coffer between the beams to house all of the services, and they’re sort of pushed up into those recesses between the beams and relying really on these penetrations through the beams to connect all of these services down and along in the north-south, the primary direction.

Jonathan: Just to add to that, the what this was one of the main – main things that frustrated us on C2, or Darren, sorry, International Sydney, was the service of coordination and making up penetrations in these beams.

Seeing it was very, very difficult and there’s a lot of work going into getting that right, from a clash detection and from a structural adequacy, when it comes to penetrating these glulam beams with – to the extent that on Dharamu, on International Sydney, we had to develop a technology in partnership with our supplier and Stuttgart University in Germany, to reinforce these beams with an LVL that had never been done before.

We like what we’ve invented or created here, and we think it’s fantastic. At the same time, it proved to be – these beams were almost twice as expensive as the standard glulam beam. And hence, that was a key driver on the project next door, Daramu House Sydney – we rotate the beams in the opposite direction so that we didn’t penetrate them nearly as much with surfaces. We basically reduced our beam penetration by about 70 percent on Daramu House compared to International Sydney.

It is a different look, it’s a different feel. We have an option going forward. You know, the architect now has an option, which is supported by good engineering and past projects that we’ve developed. You can judge the look and feel as to what you prefer. Certainly, this one here is, I believe, is an easier fit-out design and possibly easier for a churning for a tenant. However, from a COPS perspective, it’s definitely cheaper not to penetrate the beams. But there’s there’s more to it than just the tenant and cost, there’s other things to consider.

On the fit-out perspective again, both tenants embraced this expression of the structure of the building, and the exposed services, which adds to this sort of honest, authentic character of the spaces. And the fit-out was predominantly sort of bringing in loose furniture, augmenting the services with additional vapor lighting or whatever was needed, and screens and walls were needed to get some acoustic privacy. And these services sort of laid out on an orthogonal grid as part of the part of the character.

So stairs again, authentic. We wanted to encourage use of the stairs up through both buildings, so they’re very visible, they’re very prominent on the floor plates to encourage that use, lined with hardwood, again recycled Australian hardwood on the treads, and structurally, use CLT and glulam for the structure.

Jonathan: Just on that – on that photo on that last one, one of the key differences between the two projects was on the latter project, we decided not to expose the end grain. The end grain is a challenge to keep an aesthetic appearance during the construction phase because it’s more susceptible to sucking water, and it distorts or visually distorts anyway. So hence our desire to cap all these pieces and have less exposure in the grain product.

The lift shaft was one opportunity that we identified, which is a little bit unexpected, in International House, which is the lift shaft – seven stories of vertical CLT, which under construction, you could look up from bottom to top, and it’s quite incredible. And again, represents the authenticity of these buildings. They’re not relying on concrete cores like a lot of hybrid timber buildings are – they are fully authentic CLT cores, stairs, roofs.

So we thought – one – in Daramu, we wanted to sort of express that, not only during construction but also in operation. So the lift shafts being against the western elevation have this beautiful sun pouring into the seven stories of the lift shaft. And when you hop into the glass, the lift car, it is all glass, so you sort of really feel like you’re in this timber shaft all the way up through the building. And again, pushing the possibilities of the machinery.

So these beautiful five-axis CNC machines can cut doors and penetrations into beams and walls, can also make art. So in the lobby of Daramu House, we repurpose the CNC machine to create some art, which you can probably recognize some of those original foreshore lines. It was based on the sort of that changing character of the foreshore of Barangaroo.

And using the materials that the hardwood inlays on the left-hand side, you can see there were chambers that were actually reclaimed from the old 1900 walls from Barangaroo and reused, not only in the buildings but in this, in this half wall. That’s a – it’s a pretty fascinating thing.

I think we just need to step on a little bit further. Is a lot of the recycled wood in this building – actually all of the hardwood in this building is from recycled sources, either old telegraph poles been disused, old bridges which are no longer suitable or fit for purpose.

You know, timber is one of these few products which you can roll on from one project to another, and yeah great sustainability credentials, but also from a heritage perspective, you get so much more value when you can incorporate this into your design, into your building. And also with your tenant as well, that they – it’s a very difficult thing to quantify from a value proposition perspective, but we know it exists, and we know it’s it’s warmly embraced.

So as a builder and a project manager, it’s easier to do that on a timber project than perhaps some of our more concrete, glass, aluminium buildings. It just seems to fit a lot better obviously.

So with the cassette system, obviously there’s a there’s a huge potential for future flexibility for tenants, either taking out the whole cassette or the CLT component between the secondary beams, as in this instance to incorporate voids, there’s openings between between levels. And then if a future tenant doesn’t require that, replacing the cassettes or the CLT floors.

So opportunities that are much more difficult with post-tension concrete, for example. And and also we discovered too, having our flexibility in our design so that you could allow future tenant stairs and atrium stair. The grid does influence that.

I would be comfortable saying that we probably have greater flexibility in C1 than in C2, I’m sorry they’re the old names, than International Health Sydney. And and that was part of the evolution of connections, part of the evolution of structural orientations. But we have a probably greater flexibility in these in abilities to put in these staircases than what I see in our PT decks in concrete.

Yeah, so obviously a lot of lessons learned in construction and delivery. There was a lot of planning for the first and for the second. And I think that’s one of Jeremy’s messages which is the planning planning planning. Pre- planning, just so you know what to expect. 

It arrives in the right sequencing, the right order for lifting and everything along the delivery chain has been assessed. All the way back to design, because in design a lot of that influences the ultimate assembly of the parts.  What connectors are used, how amelia,  how many elements,  how they’re joined and then looking forward to like the connection with facades, the roof insulation.

All the aspects in design then feed back to the rapid assembly of these projects. Just on that photo talking about lessons learned we built the left building down international Sydney with a tower mobile cranes on this one. We did with tower cranes, we do it again with tower cranes. This building almost warranted two tower cranes.

You just get um faster lifting speeds with tower cranes but also when you get winded out you tend to get winded up earlier on a mobile crane than you will with a tower crane. And also because we have our own crews, if we have to use, if we do get rained out, we can use the crane crew for other tasks on the project, whereas the mobile crews tend to not get re-mobilized for other tasks.

The materials handling was fundamentally similar other than the tower ground I just mentioned before, and we probably did less prefabrication on Daramu than in this. From a lift core perspective, we decided to penalize the difficulties here and lift them up in segments rather than as in whole cores.

We did frame the K bracing, you can just see in that photo. Maybe Jonathan, put your cursor on on the lift core. We frame that as one lift so there’s two K bracings with beam and post in there. And for some reason, sorry, my computer just turned off for a second, I had to refresh.

Column standing up with a Franna crane walking across the deck, a tractor vehicle walking across the deck was fine. You can easily design that in even with a cassette system where the CLT slabs are 120mm thick. And standing all the columns with the tower cranes, down in the beams of tower crane, sorry, standing in columns within my eater but standing at beams and lift core with the tower cranes.

We didn’t use netting on this system, you can see there’s no scaffolds around the building. We felt that there’s not much to fall out of these buildings, therefore not like a formwork conventional concrete building where you have lots of propping and table forms, et cetera, and people working on the edges when they’re erecting and stripping those formworks. As a consequence, as a business we felt comfortable enough not to put traditional formwork edge protection such as scaffolds or screens, rather we put hand rail systems which kept people away from it.

We controlled the amount of people in the deck, this deck here had at no more than 14 people working on it when it was in a live state, i.e. during the structural phase, and we had a 14-person crew on on Daramu House, and we had an eight-person crew on on International Sydney for the entire structures. So you can control your workforces a lot more.

That’s looking back at the International Sydney to the south. We did start using the scaffold in the lower decks because we had concrete and as a business with the former we thought that was appropriate, but as soon as we got above that concrete level on level one and started running timber, we stopped it there. It’s a significant saving because there’s probably about a million dollars of scaffold there that you don’t have to use.

In the next slides, looking at the sister to Sydney, sorry we’ve jumped slide. That’s all right. We’re looking down on the roof slab of of International House Sarah Darren House on the right there you can see we’re prepping it now for waterproofing. From a structural perspective, these went up, the one on the right went up slightly faster than the left building.

And that’s a it certainly went up a lot faster given the square meter difference, you know the the right hand building Darren House is 50% larger. And we were delivering it with one crane so how do we do that? We did that with better connections, we did that with simpler floor plans, floor plates I should say.

We did that with easier columns and beams to bolt together. And so a lot of lessons learned from International Sydney, I mean you can see that sort of portrayed in here. There was a there was a month saving an overall construction time but in structural time there was about three to four weeks saving of the 12-week structural program.

With the confidence that we got from International Sydney, we could develop the design much faster and we went from a seven month process down to four month process to stress. These timber buildings need more time up front than the concrete buildings because there’s a lot of procurement going on before you even start on site. Concrete buildings we tend to procure as we start the construction, whereas timber we procure well before we start the construction.

We got a lot of confidence in, in from International Sydney and that allowed us to play with the geometries of these buildings. That does slow you down a little bit no doubt. We didn’t have, had these curves, they they are slower and they are more expensive but they add another level of complexity and beauty to the building, not just from the people outside the building but also the people inside the building.

Rectilinear, square and flat, and yeah exactly. And I think we’ve proven that that’s not the case. So Darren in the House was all about proving that the things that the critics would say about timber buildings, that had to be rectilinear and geometrically and oblong, I think we’ve demonstrated here that’s not the case.

And yes, that is an expensive feature, that it’s a it’s it’s one of those ones we want to use as a test case to prove to people that you don’t have to go down this pathway. Would we do it differently again? Probably slightly. And there’s always a lesson from every job that you’re on and but I wouldn’t be afraid of doing it again and we should be encouraged to keep exploring in this direction.

From a cost perspective, these buildings are proving to be slightly more expensive than concrete, it does depend on the exchange rate of the day if you’re procuring from overseas. However, I think it would be fair to say timber buildings, generally speaking, you’re getting cheaper onshore.

We’ve now got good supply onshore through use of people like KleinTimber who are really delving into the space of Glulam and CLT. Their CLT company Laminex, and their Queensland glulam plants, now allow you to procure everything you need onshore.

And if you don’t feel that’s competitive you can look offshore, but I think that the gap has certainly closed significantly with the modernization of their plants, which is great. We can do homegrown materials using radiata which from a performance perspective is not quite as good as the spruce that you’re seeing in those photos but it’s pretty close.

You know there’s not a lot of differences and it’s also nice to have an onshore supplier in the sense that you know you don’t have to worry about transportation, you don’t have to worry about import duties, you don’t have to worry about the overseas vagaries. Timber was the only option, that’s correct. It’s a great domestic choice now, yep.

From a safety perspective, these, we had no injuries on, no lost time injuries sorry on International House Sydney and we have one lost time injury on Daramu House Sydney and that was during the stripping of the formwork concrete so we’re finding they are, the small injuries are roughly about the same way that someone cuts their finger on something but the the lost time injuries, more significant injuries requiring medical assistance, are significantly lower.

And that’s that’s the critical mass possibly is not there for really good statistics but we’ve done four or five of these buildings in Australia now. We’re doing a lot of work overseas in the US and in and in London and Milan. You know the the jury is still out but on my gut feel from an anecdotal perspective and it’s not the least company line but I’m pretty sure these buildings are safer and that’s generally generally the accepted of people in the industry that they’re going up very safely.

And I think because there’s a lot less people on site during the structural phase and there’s a lot less things to fall out of the building during the erection process.

Next slide is, I can’t see it and here it comes. Just generally speaking, the erection of these buildings is not that dissimilar to a structural steel building you know, you you bolt together your structure, you run your facade up behind it. That facade is, you’ll see in places only two floors behind the leading deck.

You can’t achieve that on a concrete building with screens, it’s just not achievable because the screens normally occupy four to five floors during the curing phase of the concrete so that is one benefit. You tend to lock these buildings up from a waterproofing perspective significantly earlier, which is a really desirable outcome for a builder.

I like this too because it demonstrates a very clear glass, and that’s a computer animated image there but the previous one is it’s a lovely clear glass which now we showcase structure we don’t do that very much in conventional concrete structures, but we do do it in our infrastructure. It’s a natural finish, sorry, it’s a finisher freebie in many ways which you don’t have to do anything with and it gives a lovely context an exposure of a natural product in an otherwise unnatural, inhabited space.

Thanks, so we’re really happy that both of these buildings have won multiple awards, both national and international awards and across the spectrum of the award so architectural awards, property development awards, sustainability awards, timber awards. At the last, a couple of years ago, International House was awarded the best use of certified timber in the world.

And really sort of proud of the evolution between the first and the second, and soon to be the second and third timber buildings and I think we’re still at the start of this evolution.  It’s got a long way to go. A lot more efficiencies to sort of get out of the both the design and the coordination and the delivery phases. 

And so we’re very excited about this office, apology for for massacre and to add to that, I mean there’s a bit of a quiet patch we’re going through in Australia with the approvals of of timber structures of these nature. As you start to go of 25 meters particularly these ones under these are just under 25 meters effective height so they’re easier to get approved. That’s it. The feedback from the tenants sir is extreme. 

Both tenants in both buildings is extremely positive. The the information that we’re getting from supporting businesses like Planet Arc is lower, lower um uhuh absenteeism, um higher productivity. However you want to measure that, um you know lower blood pressure, lower heartbeats, all that kind of thing. These are all healthy outcomes, um which is a it should be a strong incentive in your decision-making process that if you can get better productivity or better tenant outcomes in a structure, then then why wouldn’t we go for it more readily?

Um, I think the technology, the engineering is there now. Um, the answers uh we have them, um therefore it should be we now have confidence to progress and go harder and faster with these projects. We shouldn’t be scared. But also sustainability, we haven’t even touched on sustainability, and that’s that’s part of the beauty of these buildings is that it’s inherently sustainable even without the green roof and the photovoltaics.

The timber, the structure itself is a renewable resource absorbing greenhouse gases. So you don’t really have to sell it on those on those terms. It’s inherently sustainable.

Both of these buildings are six star green stars, so it does have all the other bells and whistles, but even without those, just the timber structure replacing a concrete structure has enormous progress on embodied energy. And again, the more of these buildings that we construct our cities from, the um the closer we are to getting our greenhouse gas footprints down in Australia.

So I think we’ve answered the CPD questions along the way, but if not, reach out to me at that my Instagram handle down the bottom there and I’ll fill it in for you. All right, well thank you, thank you Jonathan and Jeremy, very much. It’s a very, very good, excellent presentation. And again you’re just absolutely wonderful, and thank you. You’ve addressed the subject. We have a number of questions that uh we’ll try to address, and uh I’ll moderate this for you. We’ll just go through the one that was asked twice is first.

So we have one from Andre and also from Lisa: how was the acoustics between the floors dealt with? So can we, yeah? So it needed to meet the all of the Property Council controls for acoustics between floors, so it’s got a high level of acoustic separation that was achieved with the combination of elements.

First of all is obviously the CLT floor itself, and then on top of that is an access floor over all levels, um which if you don’t know the access floor, it’s an air void to run all the cables and data and electricity through. So it’s a very good alternative for flexible workplace arrangements because you’re not relying on overhead cables.

And then on top of that is the the secondary floor, the raised floor on resilient mounts, which is a dense fiber cement plate. And then the four floor finish on top of that, the either carpet or timber. And the combinations of all those layers provided the separation and the the impact sound suppression.

Just uh, just to add to that Jonathan, we did allow 20% acoustic insulation to the soffits of all buildings of all office spaces. We didn’t actually use any of that allowance because when we were doing the testing, um the reverberation particularly was coming back fine, and the um and sound transition was coming back fine.

So we met all the requirements of PCA grade, which is our guiding body over here in Australia, and we didn’t feel that we need to have any reverberation issues. So no insulation, no acoustic insulation was provided in these buildings except between the side edge and the floor, that was where we did use a little bit, just underneath the smoke seal at the facade.

While you’re there Jeremy, this question from Tim is there any difference in the Florida floor height between the buildings?

Uh yeah, there is about 50 mills. So one is 3.625 on Durham on International Sydney, and I think we went three point six, no we went three point seven sorry I think on um Daramu House. So about 75 no difference, um we were we were tight on our Florida floors, um you know we were limited in height because of planning consent conditions. So we um we felt we were too tight on on International, now Sydney at three six two five, it’s it’s achievable but it was hard work, um so we went to 3.7 on the other building and that um that extra 75 mil between floors was well received.

Okay, thank you. A question on embodied carbon and carbon sequestered from Nick and Damian: was there a comparison study done between the two buildings, and just so what was the what was it?

Yeah, that’s that’s continuing to be done. Both buildings have performed exceptionally well. In fact, um if you look at the overall picture, there’s a few little tricks we’ve put in on on Dharamu House which make it an extremely green building.

Both of these buildings are the greenest buildings of all of Barangaroo, and Barangaroo is an extremely green precinct, um but if you look at the embodied carbon, um if you look at it per square meter and you you take away all the technology, you just look at the raw structure.

It’s slightly higher in Dharami House simply because it was more timber per square meter, um and but it’s only marginally, um. I think the overriding factor is is that you achieve 50% of your goals from a carbon sequester without sequestering it. You achieve 50% of your your carbon targets just by going with timber versus concrete.

Okay, another question from Lisa and changes change direction: any concern about the green roof moisture and durability in using CLT?

Um, I’ll answer that, it’s a little bit cautious that one, um, is there a yes there is extreme consideration going into not getting timber, particularly soft wood, wet, um we’ve learned a lot from both buildings. First building was a concrete roof, the second when I say concrete roof had a concrete wearing slab of 70mm on top of it, this one has a has a soil and we actively water it with an irrigation system.

Separating, preventing the timber getting wet is a struggle, and there’s lots of constraints which impact that struggle and how severe it can be, but my suggestion would be it is achievable. We have had, and I’ll put my hand up, we’ve had a small leak at the floor waste on Baramu House at two of the four-way, sorry, and that was more of an installation issue as opposed to a design issue, but you know installation is made hard by complex design, so lessons learned, yes, and is it good, it’s great but it can be done better and we now know how to do that as well.

Mass Timber Building Design: Fire Safety and Acoustics

Mass Timber High Rise Construction Explained