Ep 102 - Upfront Considerations for Post and Beam

Adam Jones (00:03):

So, thank you so much for coming on the podcast. Lisa, can you please start by telling us a little bit about yourself and what you do?

Lisa Oliver (00:22):

Well, thanks for having me on the show, Adam. So, I'm a structural engineer and I work for a consulting company called Holmes. And I'm based in Christchurch, New Zealand. Um, I've been a structural engineer for around 17 years, and during that time I've worked on all sorts of buildings. Um, but from early in my career I was really interested in timber and was fortunate enough to get to work on my first timber project quite early on which was a display hall for aircraft at a transport museum in Auckland. Now, that project was a great experience. We had a really collaborative design team from the architects through to the suppliers and even back and this was back in about 2009, a lifecycle assessment was done comparing the as-built timber structure with an equivalent steel design that we did. So, showing just how much better the timber performed from a sustainability perspective. So that was at the beginning of my career up in Auckland. My move to Christchurch, which is where I'm now based, was prompted by the Canterbury Earthquakes. So, I have a long list of assessment and strengthening projects on my cv. Uh, but I've also worked for a couple of years over in the Netherlands and was able to work on a few timber concepts over there.

(01:55):

Fast forward to today and a big part of my role with Holmes is championing both timber and sustainability. I'm also the vice president of the New Zealand Timber Design Society and recently was part of a governance group for the establishment of the New Zealand Timber Design Center, which is a new facility still being established over here in New Zealand. That will be the equivalent of wood solutions in Australia and provide similar services, but for the New Zealand market. So that's really exciting. Uh, and also in the timber space, I have been involved in the development of some design guidance, which is how the topic of today's webinar has come about. So, with another colleague of mine, Ben White, we co-authored a high-level design guide on post and beam construction in the new for the New Zealand context.

Adam Jones (03:04):

Fantastic. And you probably gonna be humble, Lisa, but you, you got more experience than most, you know, getting onto this stuff really early. So, we're lucky to be able to be speaking to you today. Um, and I've got enormous amounts of respect for the New Zealand team of Design Society. Some of the best technical information in terms of your guides. Also, your webinars are phenomenal, and we are speaking about the Post and Beam ones you've already co-authored. So, can you just tell us a little bit about the reasoning and the drivers behind creating this guide?

Lisa Oliver (03:37):

Um, well I actually think that I've been involved with more timber projects that haven't gone ahead and been built than ones that have, and

Adam Jones (03:46):

I totally understand that <laugh>.

 

Lisa Oliver (03:48):

Yeah, unfortunately, I don't think it's uncommon and there's lots of reasons that these projects don't get off the ground, but often it's because the project teams aren't as familiar designing with timber is with other materials, so they don't have that same gut feel of what's going to work and what you need to think about early in the design process. And so this obviously leads to inefficient structures that sometimes just don't work and or to make them work a really expensive, so we wanted to provide a guide that would give people a bit of a head start <laugh>, so help architects and engineers develop concept timber concepts that would set them up to deliver successful timber projects. And Post and Beam is a really simple system. Um, so a good one, the start that allows, um, you know, there's lots of benefits for a temp post and beam system, you know, open flexible spaces, so will allow the development of more types of timber buildings to be built out of timber.

Adam Jones (05:00):

Yeah, fantastic. And so the guide has a lot of different information, and you'd think that the highest leverage points is that early auctioneering stage, would you say at the very start? And what are, I mean, what's the role of a structural engineer, um, beginning at the start of the process and how might it be a little bit different to what we're used to?

Lisa Oliver (05:22):

Well, again, it comes to that, the fact that generally, the design teams aren't as familiar with what's possible in, in timber. So I think it's really important that right from the beginning of the project, the structural engineer is working closely with the architect to ensure that the grid layouts and floor depths are optimized for timber. Um, in the design guide we include things like span tables, and examples of connections that can be used for post and beam construction to help auctioneer these early stages. I often find that people have kind of got it in their heads that the grids might need to be smaller, but they underestimate the overall floor depth still

Adam Jones (06:09):

Mm-hmm.

Lisa Oliver (06:12):

So yeah, which can cause huge problems later on if you then realize that the services need to go under the beams or you've got to add even more depth for acoustic and fire treatments. Yeah. So having a deep under, you know, getting that right from the beginning is a huge help.

Adam Jones (06:33):

Yeah. And I guess from the, um, you know, multidisciplinary point of view, it's like a, something that comes up on the podcast a bit, it's having enough people in the room at the start. I mean, you know, from your perspective who, who needs to be in the room and what sort of considerations are best to, to go on at the very beginning of the project?

Lisa Oliver (06:54):

Uh, the more of the full design team you can have in at the beginning <laugh> the better. Um, so as well as the architect and engineer, it's important to get that early input from the services acoustic and fire consultants. Um, and although I know clients hate locking in suppliers early if you can get a supplier on board right from the beginning, that so much experience and value that they can add sort of making sure that those designs are optimized and can be built efficiently. Um, so with all these players and board and if they all have a deep understanding of how timber behaves, then most of the big risks for timber projects can be designed outright from the beginning.

Adam Jones (07:44):

Yep. Well, I guess it's, uh, is it easier said than done? Because I mean, how much timber, you know, consultants with timber experience that are out there that you can get on board and does it, you need the full team, I'd imagine with that experience to have a success to make sure that we're, you know, you're not looking locking in a port design at the very start, is that right?

Lisa Oliver (08:06):

I mean, with the, you know, the increase in the amount of timber that's being built there, there will be lots of people learning as they go. And so I think it's important if you're not, if you don't have an experienced team, just to factor that into the design process and make sure that you're spending that time early in the design, not rushing through the concept, you know, making sure that you're spending more time upfront and getting the input from all those different players before moving to the next stages.

Adam Jones (08:41):

Yep. Well, even from an engineering point of view, do you think it's surprising, like say someone's doing it for their first ever engineering job, is it very easy to undercook the amount of time it really takes to actually do a design? I'd imagine, especially in the New Zealand context, the seismic requirements, yeah, have is that, is that it?

Lisa Oliver (08:58):

It is very easy to undercook the design and there aren't as many cookbook solutions for timber out there yet either. Um, we tend to be doing all the connections and things from first principles and everyone is a little bit different, which just yeah, takes a lot more time than looking up a steel cleat in a table.

Adam Jones (09:25):

Mm. Well hopefully. Do you think we might get there one day where with every design, maybe five years and hopefully that'll help drive down the cost and overall simplicity and really get rid of some of those mistakes that we might be used to?

Lisa Oliver (09:39):

Yeah, well some of the, the innovations in this space that I think are really exciting at the moment are not the ones that are making us go bigger, taller, you know, larger, but are the ones that are focused on standardizing these timber systems and, you know, allowing repetition so that we can build normal buildings outta timber efficiently and, cost effectively. Um, and which will increase the total volume in our off timber used substantially. So, at Holmes, we are really trying to implement these efficiencies in our designs, so look for them and repeat them from project to project. Um, and yeah, part of the Holmes family is a company called Home Solutions that has a research and testing - is a research and testing facility. And they're also quite heavily involved in the mass timber space and have done quite a lot of work on a suite of connections that will, that we are really excited about in this space of doing exactly that, trying to standardize a timber system. And that those connections have been picked up by Hilty who are going bring them to market. So, watch this space. Very exciting.

Adam Jones (11:04):

That is super exciting, and it solves a lot of issues with that replication. Now, look what was back to the beginning of the project. What are some of the other key ticket items at the very start that we need to be getting right do you think?

Lisa Oliver (11:19):

Well, I've got, I've got a long list, but <laugh>, that's totally fine.

(11:24):

As well as getting that efficient grid system and realistic, floor-to-floor height, I think it's important to consider how you're going to achieve fire and acoustic performance. Um, because if you try and add those in later in the design, it has all sorts of flow on impacts to other parts of the design. Um, and another area that I think needs to be considered earlier than you might with other types of construction is the fabrication and erection of the components. Um, so crane time and increased labor obviously has a direct impact on construction costs. So, it's really important to be thinking about the number of lifts you're going to do with a crane, and then how long it takes to actually achieve the connections on site. Um, going back to some of the work that Home Solutions have done, again, they've done quite a lot of time in motion study on different, installing different connections types, and it's amazing how much variation there is and how long some connections can take to actually install in the field and how difficult they are, how, you know, how hard it is on the people doing the work, and then how hard it is also to do the QA on them, you know, to actually see that the connections have been installed correctly.

(12:59):

So, taking all of that into account as you're designing.

Adam Jones (13:04):

Yeah, and it's huge. And yeah, there's, at the end of the day, it's people implementing these and it's not just, you know, skewed screws, it 300 standards, it's a, if you multiply it out, there's a lot of, a lot of screws are going, it is that people have to do it at the end of the day, which we might forget sometimes that, you know, diameter or something. Uh, I was made, I think it was the same conference we went to, it was the New Zealand woodworks conference. And I remember just one of the presentations talking about never specify screws of above certain height, uh, sorry, uh, diameter. And, um, yeah, for that particular project it was the biggest mass team project in the world. And the biggest issue they had was just that the screw diameter not being practical.

Lisa Oliver (13:44):

Mm-hmm. Yeah.

Adam Jones (13:47):

Um, what are the, what are some of the other major problems and things that designers need to be watching out for in these buildings?

 

Lisa Oliver (13:56):

Uh, two of the things that spring to mind are tolerance and weather protection. And I think both of those were also mentioned in depth that the conference you, um, mentioned there. Um, but I think with tolerance or those CNC machining can mean that the timber elements themselves are fabric fabricated very accurately. We still need to remember that there still needs to be design tolerance for constructability. Um, and often, you know, these timber elements are being erected on a concrete substructure or concrete foundation. So, it's not just the timber elements that we need to consider, it's what they're being connected to and the fact that timbers are natural material, so it shrinks and swells. So, we need to design for the tolerance for that, taking that into account as well, especially during construction. I've heard about, you know, instances where local swelling at the end of a column has meant that, you can't get the beam to fit between the two columns, or even instances where swelling has fractured screws that are installed particular to the grain.

(15:21):

Um, and you just don't have to think about this when you are designing with steel or concrete. So, it's an added layer of complexity for timber designs, but it's not insurmountable. We've got solutions for, um, you know, practical solutions. That does mean you can still design in timber in a cost-effective manner. Um, so I think I also mentioned weather protection and of course, that's to help manage the moisture in a structure. So, it's important that just all projects when they get to the site or on the elements on their way to sites have a moisture management plan to limit the impact of that moisture movement. And there's two basic components to that. One, avoiding prolonged exposure of the timber to water, having controls in place for that, and then before the timber is enclosed in the structure, making sure it's got time to dry. So, yeah, sounds simple, but in reality, in reality can be a challenge to manage.

Adam Jones (16:38):

Yeah, I like it. There's a lot in that. Well, uh, yeah, there's been a lot of wisdom that we've been lucky to hear. What are some of the latest innovations that you are seeing in this space that gets you excited?

Lisa Oliver (16:50):

I mentioned the connections, the sweeter connections that the home solution teams are working on. Um, but in that same sort of field of innovation that will bring timber to the masses if you like, you know, all the different suppliers and fabricators who are working on like different prefabrication, components and, bringing them together. And that's why I really think organizations like the Timber Design Center and Good Solutions, I don't, you wouldn't necessarily call them an innovation, but they foster innovation, they foster collaboration, which is going to really increase the uptake in timber.

Adam Jones (17:45):

Yep. Well, it's an exciting future. You've mentioned a few things. Is there anything else you'd like to plug or any places you'd like listeners to go and learn more what we've been speaking about today?

Lisa Oliver (17:59):

Um, well, I guess our team at Holmes are really passionate about timber projects and always keen to hear about new opportunities. So, we are based here in New Zealand, this is where we Holmes, um, started, but our fire team have got quite a good presence in Australia and work on quite a lot of big timber projects over there. We're also present in the US and the Netherlands, so we've got a broad, experience base to draw on. And yeah, always keen to hear about new project, timber project opportunities. And I just want to mention the New Zealand Timber Design Center. Again, it's more of a watch the space because it's still in the establishment phase at the moment, but I think that will be another great resource for those, not just those who are starting out on their timber journey, but of collaborative space for those who have, you know, are part of the team already.

Adam Jones (19:16):

Yep. Well, that's, uh, that's great. Well, thanks so much for coming on the podcast, Lisa, it's been, it's been a great learning session with yourself today. Appreciate it.

Lisa Oliver (19:26):

No problem.