“Sustainable buildings focus on what's invisible, not visible”

In this episode of The Mindful Builder, we sit down with Roberto Petruzzi, an Environmentally Sustainable Design (ESD) specialist, to unpack what building performance and energy efficiency really mean in practice. We talk about energy modelling, building science, and why the details you cannot see often matter most for comfort, durability, and running costs.

Roberto explains the unseen layers that shape high-performance homes, including airtightness, thermal performance, insulation continuity, ventilation strategy, glazing choices, and shading. These are the decisions that determine whether a home feels stable and comfortable, or whether it runs hot, cold, damp, or expensive. Sustainability is not about ticking boxes. It is about designing buildings that perform as intended in their climate.

One of the most interesting parts of the conversation is Roberto’s take on restraint. Sometimes, the most sustainable decision is choosing not to build when financial or environmental constraints do not stack up. It is not a popular message in construction, but it is an honest one. Sustainability is not only about what you add to a project. It is also about what you avoid.

We also dig into collaboration across the whole project team. Architects, engineers, builders, and clients need to be aligned early, because the biggest performance wins happen in the early design stage. If you care about sustainable architecture, energy efficient homes, ESD, and building better in Australia, this episode will give you a clearer way to think about it.

👇 CHAPTER MARKERS 👇

00:00 Welcome

03:41 Budget Reality Checks

05:48 Meet Robert Petruzzie

07:26 From Switzerland to ESD

09:24 What ESD Consultants Do

11:12 Council Plans and Greenwashing

15:17 Balancing Daylight and Thermal

16:33 Perfect Buildings and Tradeoffs

20:56 NAB HERS vs Passive House

24:41 Air Change Assumptions

25:37 HERS Rating Limitations

26:21 What Is WUFI

27:38 Retrofit Moisture Risks

30:59 Reading Mould Index

35:00 Parklife Wall Assemblies

39:02 Airtightness Skills Gap

40:02 Building the Backyard Pod

43:24 Retrofit Priorities

44:49 Curiosity for Apprentices

45:52 Mandatory Airtight Testing

46:50 Wrap Up

LINKS:

Connect with Roberto:

https://hipvhype.com/our-approach/our-people?t=Roberto-Petruzzi

Our Sponsors:

Proclima - https://mindful-builder.captivate.fm/proclima

MEGT - https://mindful-builder.captivate.fm/megt

Connect with us on Instagram: @themindfulbuilderpod

Connect with Hamish:

Instagram: @sanctumhomes

Website: www.yoursanctum.com.au/

Connect with Matt:

Instagram: @carlandconstructions

Website: www.carlandconstructions.com/

Mentioned in this episode:

Proclima Sponsor

Welcome back to another episode of The Mindful Builder.

, We're recording here at Hit the Hype in the Proclima studio, Built To Last So

I'm here with my good friend, Hamish, uh, my co-host, but I'm also here with Rob.

And I actually met Rob just as COVID had started.

Yeah.

And Rob had reached out me to Billy's house in Altona.

Cool story because the house didn't get built.

And I don't mean that in a, in a bad way, but it's a

sucker.

Yeah.

But it's a kind of cool, what I like about it is you had, it's

so cool you didn't get

a house, but, and we'll get to this, but what I like the fact that why we didn't

build it is because you actually made a decision not to build it, rather than I

see so many people just keep stretching and stretching and then just pulling

themself into this world of like stress.

Were you very confident?

Like, we just can't do this.

And that is a awesome outcome.

Can you tell us a bit more about that?

Well, from my perspective as the builder,

yeah, no, absolutely.

I think you're totally right.

Um, it was, uh, disappointing and, and sad that we didn't get there.

Um, but it was definitely the good decision because we would've

been in such a financial hardship.

Um, now, but also we wouldn't have.

Actually being able to, to go past the, you know, past the design stages anyway.

Yeah.

Um,

it was a cool, as a design, it was like fucking cool.

Yeah.

It, it was an interesting design.

It started very ambitious, uh, and then got scaled back.

Um, you probably remember that.

Um,

but it was affordable though at the start.

So pre COVID, like the numbers worked, like, it was like, yeah.

Sweet.

So it was the perfect, like, Hey, let's just reprice this because of COVID and.

We just, it was,

yeah.

Yeah.

And it took a, it took a long time as well to go past council,

so that obviously, um, oh,

so you were pretty well progressed with the design, so through council, you

Yeah, we, we obtained planning permit.

Yeah.

You got covenant removed from memory.

Yeah, we, yeah.

Yeah.

Um, but yeah, I, I think I'm totally on board.

Like it's good that we didn't build it.

Yeah.

Uh, and if I think back at it.

Probably I pushed a little bit longer than what I should have.

I think that I went out nice to market with other builders.

Uh, I sort of, you know, I still believed that we could build it for

what the budget was, while probably maybe in, you had it already, like, no,

I think that's a good, can't be built.

But that's the, but that's the best outcome.

Like that is like you, you tested the waters, you saw what was there.

It didn't work.

You tested some more waters, like you gotta throw things at the project,

but you don't have to be stupid.

And hey, we got, what I see constantly is people in your

position go, nah, I'll be fine.

Like, nah, that just, that budget mustn't be right.

We'll get there, don't worry.

But they keep progressing.

Progressing.

They get to the end and then the number's still the same.

And they're like, but why is it so expensive?

And they've just spent a hundred thousand dollars on design fees.

Consultant fees and then they can't build a house.

It's, you know what I mean?

It's, I think it's hard to shut down a dream sometimes.

Yeah.

Um, and I think that's just, there's, that sings true to so many

people who just keep pushing and pushing and hoping for the best.

Like, you know, I think, look, we've, I dunno how many times you said

it, but getting a builder on board and the team involved and from the

very, very beginning is, but we did.

That

is the way to go.

Yeah.

But you've, you've got this unfortunate.

You know, situation of COVID that no one could have predicted.

But it still happens now.

And I think that's the beauty of it.

That's the reason why we do it.

And I actually had a client yesterday pulled the pin on a project and I was

like, this is a weird email to write.

And I actually wrote it this morning.

I'm like, this is what I want to hear from you.

Like the reason why we test the budget early and was the budget meets brief in

this case, it didn't buy a huge amount.

They didn't go, oh, hopefully we can get it.

No.

They had the courage to be like, no, we're not doing this.

Yeah.

And I think that is like something that it's not sexy.

You can't put on Instagram, you can't talk about that on social media because

it's the job that you didn't win and then you're perceived as too expensive.

I've encouraged 'em to maybe get a few other market quotes, but the reality

is I got two estimators to price this.

Yeah.

And so.

I didn't even price it.

The market rate is dictated by them and what their billions of

dollars of estimation per year.

So that's what they're gonna get.

I mean, it's probably not exactly what we're gonna talk about, Robert, and I'm

gonna get through it in a sec, but I had exactly the same conversation with someone

last night where they've come to me, gone through planning, um, I'm like, you're

probably $600,000 off where it's gonna be.

She goes, oh, okay.

Well what happens if you don't build it like this?

And I'm like, it's still, it's like it's the size of the home.

It's 275 square meters.

And I think you've been misled by your architect here.

I'm sorry.

Anyway, um, Robert, who are you?

And what, I was

literally about to ask that

question.

I

was like, that's gonna be my leeway

back into it.

Yeah.

What, what, what are you, why are you sitting here?

What, what, what's your role with, um, and there's an accent there as well.

Yes.

So can you guess, uh, well, I know it's Italian.

Oh, I know you, yeah, you're wrong.

Oh, right.

I should,

uh, not, not totally wrong.

Um, I'm, uh, my family's from Italy, but I was, uh, born and raised in Switzerland.

In the Italian partners with Yeah,

but you, but you speak

my, yes.

My first language is Italian.

Is it the sexiest accident we have

on my podcast so far?

Yeah, because you, because Switzerland's this sort of, um,

interesting mesh of German and Italy.

Don't you have two national languages?

We have

four.

Okay.

Of course.

And so you are up the.

I'm assuming like around the Como region up that part?

Yeah.

Yeah.

So Como obviously is in Italy, but it's uh, yes, across the border.

Across the border and yeah, probably half an hour drive, uh, from Como.

And

do you speak all the four national languages?

Probably speak six.

No, sorry.

No, I used to.

I used to.

Obviously at school we need to learn German and French plus obviously

the language of the Canton that you live in, so Italian, um.

And when I was at school, I learned all, all those.

But now it's been so long that I haven't practiced my German and French.

I can probably understand a little bit.

Yeah.

But I would find it very difficult to speak.

Yeah.

Can you still read

German, considering you live in PhD, HPP?

No.

No.

French?

Yes.

Not German.

German.

Um, so you, you, you come over here in 2009, is that right?

Yeah, yeah.

2009.

And what, how did you get into the space that you're working in now?

It was pretty much by chance.

Uh, so yeah, came in, in 2009, started my bachelor in social Science with

a major in environmental management.

And during the fir, the first or second year of uni, uh, I got myself

a job in for a, a consultancy that used to do energy audits on existing

buildings for local governments.

Um, so I got the job and slowly became somewhat passionate about buildings

and how they perform and what what can be done to make them better.

Yep.

And then from there.

Uh, I got more into the specific ESD space or rather than looking at existing

building, looking at the design stages.

And when I met you, you weren't at Hit V hype, I think.

Is that correct?

Yeah.

Or you just been.

Just started,

no, I wasn't at a VI at that time.

So at that time I was at, uh, sustainable built Environments, uh,

which is a dedicated ESD consultancy, uh, which is part of the pedal

torque group, pedal to architects.

So at that time was probably the only ESD consultancy that was integrated

in an architectural firm, which was.

Pretty good because you actually had the opportunity to

influence design very early on.

Um, sometime as the SE consultant here, we get, we get onto the project when the,

the building form is already sort of set, there is already like an approved scheme,

which for a lot of things is already difficult then to, to make improvement.

'cause

the clients are, it's like costing a project when the design's

already completely developed.

It's hard to, what are you

talking about?

We never do that.

So for those who dunno, what does ESD stand for?

Uh, environmentally sustainable design.

Yep.

Isn't everything sustainably designed though, or claims to be right now?

I guess so.

So, so what, what, what would you say your role is in a building?

Like what, what, what are you bringing to that, um, team of consultants?

Good question.

Um,

very good question, Amy.

Yeah, it is.

Thank you.

Well, your question game today.

Yep.

It really depends a little bit on, on, on the projects.

Um, now here at vip we are somewhat fortunate 'cause we, we do tend to

work with clients that have high sustainability ambition and for.

We don't just do minimum compliance work or you know, checks or your Section

J, your NA minimum compliance report.

So our role really is to.

If we start from concept design is to try and set the ambitions and the

framework, uh, for sustainability.

And

what's an example of Park Life, for example?

What might those, some of those criteria be?

Well, it could be like things like, uh.

What do we wanna achieve in terms of thermal performance?

And we speak about for park life too, for example, about, uh, NA ratings.

Yes.

What na rating we want to achieve.

Uh, what some of the indoor environment qualities that we wanna bring in.

Like, uh, you know, what materials do we want to, to work with?

Um, all the way down to, you know.

What our, what?

Our target for portable water reductions.

Yeah.

Or storm water treatment or energy generation.

Energy generation.

Yeah.

Waste.

Waste management,

waste.

Yeah.

A little bit.

Yep.

Yeah.

Yeah.

And do you have, um, say, I mean, park Life's about to get, go into construction.

Is there, I guess, some criteria that the build team needs to adhere to from,

say, waste management point of view?

Is there some goals or KPIs that you are setting within their contract?

Well, yeah.

Essentially that becomes part of, of the building permit stage.

So you know, you need to go through a planning process with council, so.

Uh, a lot of council required a sustainability management plan as

part of the application and that sets the initiatives and targets that the

development is going to, to achieve from a sustainability point of view.

Yeah.

Do you think those things that council do is just greenwashing?

So I know when I did mine, they were more focused on a bike at my own residential

house and like the fact that we were going passive house certification.

Adding, like there was not even a tick box for improving the North face

glazing or HIV or we're gonna be,

how are you gonna charge your electric car

through a plug?

Yeah, but that's what I'm saying.

No, no.

But there, there should be some.

No, but like, it was more worried about like some of the, I, I can't even

remember if like some of the stuff I had on there, but I remember having to pay

for this stupid report and I actually called James like, what the fuck is this?

Like, I just wasted a few hundred dollars on what I would call

the biggest piece of shit of, of document I've ever had to look at.

Like, it was, it was, it was purely a government tick box that they had

done to go through a planning process, but it ignored all what I would

consider the most valuable things.

That you should look at a building.

Yeah.

Okay.

I'm gonna challenge that for a second though.

'cause I think you need some kind of F frame basic framework

that everyone deals with.

I mean, isn't you are, you are an out, isn't that,

isn't that Nat hers?

Yeah.

But you are an outlier with what you're trying to build there.

No, but isn't that nat hers, that every project per the NC at that

time would've had to met a six star?

Why do we need a, like why add another layer?

They'll worry about like water consumption that I had 5,000 liters

and I, something was something like, and I can't quite remember

exactly, but it's like, oh, you got.

But, so I ticked the 2000 liter, but it's like, no, we've got five.

So do you not get more points or more, but you'd already, I

don't know, it was just this.

Yeah.

Okay.

generally as an industry, we do like to, implement what

visible and what can give you.

An indication that your building is sustainable rather than what is

invisible, which is probably what matters.

Yep.

But isn't that But architectural

role?

There is a little bit of a Yeah,

but like that's

balance.

That should be just somewhat in the architecture and it's just another

layer of, of, of non-essential paperwork that becomes a barrier to actually

them building these buildings because people then design and add these

things into it for the wrong reason.

They're adding it into tick the government.

Tick box to get through, cancel rather the building that's actually gonna matter.

And last,

yeah.

Uh, look, I, it's, I think if the solution was easy.

It, it is easy though.

Yeah.

I, I just, I disagree.

I think it's hard.

That's why people like you.

Do you think it's an easy

solution?

Oh, look, I, I think there is competing priorities.

Obviously nature's passive house.

You build your passive house, it's gonna be very energy efficient Yeah.

Comfortable and whatnot.

But it doesn't consider a lot of the other sustainability.

At initiatives or implementation that you can do.

It doesn't think about upfront carbon.

It doesn't think about sustainable transport.

Yeah.

Waste management and all of that.

And that's important as well.

Yeah,

and that's I think where, where local governments in Victoria

are trying to play a role in.

They, they understand the knowledge.

There is a national construction code, everybody needs to adhere to that

if they don't wanna go to prison.

Uh, and then, but then there is something that can be done.

I'd bit better.

You said if you don't want to go to prison, if you're build

incorrectly, you're not going to prison, you might get slapped with a,

okay.

Don't do that again.

Yeah.

Well I think

and I, but that, but these poor, my thinking is these poor.

Roadblocks along the way lead to poor outcomes because if they're doing that,

oh, I'm not gonna worry about that.

Where I, I don't know how to word this.

Well, I mean, I, I've just drawn something on my notepad here and I'm

like, put passive house in a bubble and I put star ratings in a bubble

bubble, and I put waste in a bubble.

And it's like they're almost operating individual to one another.

And is that where say someone like you in your ESD consultant role tries to then

bring it all together in a logical way?

Yeah.

Yeah.

There is, there is a little bit of that.

Yes, absolutely.

Uh, it, it is, it is a balancing act.

It is trying to, you know, if I think that the, the perfect example

is daylighting, which is something that council, especially in the,

uh, you know, uh, residential, um.

Multi-story.

Yep.

Financial space or commercial space that really, uh, look,

uh, for and thermal performance.

There is obviously a tension between the two.

You either achieve one or the other.

It's difficult to achieve both shading because Yeah.

You know, you're shading you window to wall ratio and all of that.

So yeah, our role is to try and, and find a perfect mix of initiative that

work for local governments or that.

A author that needs to tick, uh, the box, but also for the

client and for the design intent.

Yeah.

What's

perfect?

What's the perfect building then?

Look like You get a blank piece of paper.

What is that?

What, how would you, from a sustainability perspective, and the

word sustainability is so different, it's like this jigsaw puzzle.

What is it?

Because you've, 'cause you've, you're doing it.

Yeah.

Yeah.

Uh, look, uh, I think that you, you ask anyone in the team here, and

they will have a different response, but what's your, what's yours?

My, I, I'm very much, well, obviously coming from Europe and, and Switzerland.

If you go, if you've ever been to Switzerland, you'd see those buildings.

They basically, um, square boxes.

Yep.

Um.

Uh, modest window to wall ratios and

thick, thick, thick walls.

Thick wall walls.

Uh, I'm not saying that those are the perfect buildings for heavy well climate.

They're built,

they're built for that climate.

Yeah.

And they are simple.

They do their job like the floor plates.

They make sense.

I look at floor plates sometimes.

Yeah, on the project that I, that I work on here and I go like,

gee,

how can

you

leave

in that?

I guess, I guess this is where, this is where that friction, um, exists though,

because, you know, in my view, I think architecture plays such an important

role in our built environment because it needs to be aesthetically pleasing.

We just don't wanna walk down the street and just see these

monotonous boxes everywhere.

I, I agree.

We don't wanna see that.

So this is where I think it's really important to blend the two

together and make, as Liam was saying before, like, consider compromises.

And I think that's a really great term because you can't just say, well, we're

gonna do this because it looks great.

You go, okay, well let's unpack it a little bit and let's fine tune it

so it gets the best of both worlds.

So then what's the part that, so you say that you argue

about what's Im most important.

What do you think is the least important that we worry about?

That we just start?

Just why bother?

We have a convers, like what's the most over greenwashed

then sustainability aspect.

Oh gee.

Um,

put, it's alright.

It's all alright.

You're on camera?

Yeah.

You got mis

recorded.

I'm gonna have lots of enemies here.

By the end of this,

let's just say this is your opinion, right?

Because we've all got different

opinions here.

Yeah.

It's fact.

Look, we can cut this up as a

little

snippet

of our Yeah.

And we're gonna cancel you.

Look, I think, look, if, if we think about, uh, design outcome, I, I find

that when there is a tension between terminal and daylight, I think daylight.

It's not necessarily important in bedrooms since I an apartment.

Yes, I know.

I understand where it comes from.

It comes from.

Those whole very small designs, maybe Yeah.

Bedrooms without windows and totally understand that.

Yeah.

We wanna avoid that.

But I think that as long as every room in an apartment as a, as a window, a

room, you don't need, you don't need to achieve high level of daylight.

You can go outside to have daylight when you are inside the house.

Yeah.

You're sleep,

you're sleeping.

Like does it matter?

Yeah.

Yeah.

So for me that, that, that's probably.

I,

I agree.

We're, that's

that

topical, gimme something

spicy.

When we're, when we're specifically talking about, and I just wanna go

on the record, you're saying we're specifically talking about multi-res Yeah.

Apartment style buildings.

If we're talking about a single home, that's a completely different

conversation in my opinion.

Yeah,

yeah, yeah.

But if, but if we're talking about an apartment where we, we, we

desperately need these buildings.

We desperately need 'em to be thermal thermally, comfortable and efficient.

And we desperately need them to be healthy.

If the trade off of that is that there's one room with good light and then your

bedroom is a bit darker, fucking carry on.

Yeah.

That's my opinion.

Yeah, totally agree.

Yeah.

So if the same question into a residential setting, is there something,

is it the same concept we just worry about too much light in a bedroom?

Um, no, I don't.

Probably not to the same level and to be honest, like a single residential

home is unlikely to have to go through.

This level of scrutiny from a sustainability point of view,

it's, it's generally just your NATOs ratings and off you go.

Yeah.

And you've got good experience in NATOs too.

Like you, you, that was your job for a while.

For Yeah,

yeah, yeah.

Absolutely.

Um, yeah, I'm not sure what would be in, in the residential space.

What

can I then ask one question?

Sorry, I'm jumping in here because Nat, hers, how long did you do

Nat hers stuff For a few years.

Uh, yeah, I started long time ago.

I can't even remember, but that was probably the, uh,

2012.

So you were pretty embedded in like Nat Herds was the solution

and you get passive house.

Yeah.

What's

better?

Oh, look, they do, they do different things, but um.

Obviously as a, as a design tool, passive house, uh, obviously wins hands down.

And, and that's not to say that is the only tool that is from, from a

design point of view, it is good to use, but certainly it, it's up there.

What does Nat HST do that passive house then doesn't do and does well?

Like where does that beat passive house?

Well, N Nas or the, the hero.

So, or the, the software that are, um, that are using in nas, they're

there to compare Apple with Apple and, and demonstrate compliance with code.

And, and that, that's really about it.

There is nothing, nothing that, uh, nothing else.

There are differences.

Like, you know, they, the NET software use Harley data.

Um, the PHPP use monthly data, um, but.

Yeah.

I, I think that that you, you can't really compare the two.

I don't think it's fair.

They're looking, they're, they're

looking at different things though.

I know, but this is, we as an industry, we do, and this is where I wanna get out.

Maybe we shouldn't.

Well,

what

do you mean?

Like we all are passive house?

Her, not her.

It's like the.

They're different things.

I, I actually, okay, so I'm, and

I've been that

person.

Yeah.

I mean, every, everyone knows that I'm a passive house and

high performance builder.

We, like, I would say a hundred percent of our homes are getting modeled, even our

renovations are getting modeled in PHPP.

But, you know, I'm obviously part of Sustainable Bills Alliance as well.

And Jeremy Spence is a big advocate for, um, the star rating and, and

he's been using the information that he's getting outta that modeling

really well for a number of years.

So I think, you know, this is not a poo-pooing on stars

or nat hers or whatever.

I think both are really valuable.

Like modeling, regardless of what it is, let's just be agnostic for a second,

is really important, regardless of which pathway you're doing, but use it

not just as a box checking exercise.

Use it as an optimization tool.

So there's a massive difference between that.

So this is what I wanted to sort of, where I was hoping we would

potentially get to is that we are obviously very biased to passive house.

I kind of wanted to jump onto the train of like.

What does it do better and how do, yeah, how, how does, I wanted to

argue the opposite side for once.

Yeah.

The PHPP does a much more precise job at working out the electricity, the,

the energy consumption of the building.

Yeah.

There is much more inputs into it and, uh, na sits really just concern

with the thermal envelope if you want.

There is a lot of assumptions that.

I'm not, uh, current anymore.

And you know, there, there is a big research piece that is currently underway.

Yeah, Liam, Liam was

telling us us about that, which sounds super exciting and relevant.

So I actually feel like.

That tool is gonna become much more powerful and much more relevant.

Yeah, yeah, yeah.

Absolutely.

Um, and also, uh, this was a couple of years ago, I went to a conference

and, and a researcher from, I think it was a university up in Queensland.

It compared A-P-H-P-P with, with, um, the NA software.

Uh, and when you can actually put in the same assumptions and you

need to have special, um, access.

Access

to the backend.

Access to the backend.

Yep.

But the results are very, very similar between the two.

And would the biggest one be the air change assumption?

Yeah.

Yeah,

yeah.

Yeah.

Because you know that I think, is it, and you, you, what's the assumption

that NA hose makes for air changes?

Seven.

Yeah.

It depends a little bit.

'cause it changes depending on, on pressures.

So wind pressures, yeah.

And all of that.

But yeah, you can probably assume that averaging like seven thereabout.

It went from something like eight to like 9.6.

If you, if you put in

the invoices for Yeah, I would to, um, just change the, i i, it might be point

or two off you, but like that's roughly, it was a, it actually made a huge change

and I think that's a point, that's a, that's probably the point I was trying

to make before is like we choose to do passive house because we think right

now it's, it's, it's much more impactful for what we're trying to achieve.

Yeah, but they're looking at different things.

I just, you can't compare you.

They're not, they're not an apple.

And an apple.

It's a watermelon and a fricking orange, like

the only beef fight.

There's two beefs I have with Hur is one doesn't have airtight like imagine

a in a how cool for holding people accountable for the way we built.

Oh, a hundred percent.

You can agree.

At the end of the project, go back to the mad her assessor do it,

and then all of a sudden like, Hey, this is what we got above.

That's the, that's the one part, the, the other part that I don't like and

it kind of goes, you're comparing apples with apples, but you're not,

because a six star house in Melbourne is not a six star house in Sydney.

So it's kind of contradictory to that.

Yeah.

There is a whole like, again, backhand of, uh, star bands and

hitting cool loads, which is, to my understanding, it's a lot, is based on.

Economic feasibility Yeah.

Of, of achieving the, the star ratings.

And you also do, uh, wolfie modeling as well.

Yeah.

So for those who have no idea and have been living under a rock, what is wolfie?

What is a wolfie analysis?

Yeah.

Essentially, well, Wolfie is, is a software.

Yeah.

Um, the, the Agri Thermal Analysis is, is essentially a study of.

A building assembly, whether it is like a wall, a roof, or a floor.

Um, and, uh, how moisture and heat travel through that, through that assembly,

through the different components.

Um, and the idea behind this is to, to evaluate whether there are risk in

that assembly and how big those risks

are.

Hamish, can you do me a favor and tell me what WOLFIE stands for?

Yep.

Okay.

Uh,

warm.

Sounds Russian more than German, but

do you, do you not understand?

Do you know?

No.

Oh no.

You can ask Marcus.

Ah,

yeah.

Along a frames of the bus.

Um, yeah, so it's a high growth thermal analysis.

Yeah.

So basically it's looking at the risk of condensation mold

in a building, in our building.

You just

literally did what?

I got a report from Cam this morning on it.

Um, yeah.

And it's, you know what, like I feel, um.

I, I'm much more interested in that now as we as a business are kind of, not

pivoting, but we're opening up different offerings to work on existing buildings.

And I know you are doing, it's similar thing, it's a wide

field

and believe it or not, like, well, one, we've, we've got how many millions of

homes that need retrofitting, right?

Yeah.

But there's gonna be a huge problem if all of a sudden we're

just, oh, we'll slap insulation in there and make it more airtight.

Right.

We're, we're actually creating a huge problem.

However, we've got these softwares and modeling and people like yourself who can

actually, theoretically, and I'll, and I'll, and I'll say that theoretically,

because you've still gotta have someone that's gonna execute at the other end.

Yeah.

Theoretically, prove or analyze.

The changes that you're making to that building, uh, is it gonna be safe?

So I'm super interested in this stuff now because, you know, we

wanna start targeting much more of this sort of retrofit market.

Um, are you finding that, uh, you are doing more of that stuff now than you

were before, or is there becoming more of an interest or are you still in that

kind of new space, new building space?

Yeah.

It's probably a little bit of a new thing, especially in the commercial, uh, space.

Um, there are some clients that are interested in, and, and you know, we,

we, the way we approach it really in our day-to-day consulting is that obviously.

Okay.

If we just think about Section J reporting, we have

what, what is Section J

reporting?

Uh, the energy efficiency.

Um, reporting for, for compliance with the code?

Yeah.

Okay.

You know, it's similar to your, similar to NA's rating, but Okay.

But so

this is for more commercial

buildings?

Yeah.

Yeah.

This is for commercial.

Yeah.

But so.

Essentially 'cause 'cause we work a lot in commercial.

Yes.

Yep.

Um, so the way we sort of go about it is that when we review a set of drawings

with, with a wall type, with a roof detail or whatever, if we see an issue or if we

think that there is an issue with the, the assembly, we talk to the client about it

and then we, we start to educate them on what the risks are and what can be done

and how, you know, how we can help, but.

There is still little understanding, little not, we don't have many

client coming to us for Can you do a with an anther model on this?

Yeah.

And it's not the answer.

Like, I've got a project, I'm probably banging cam's head

against the wall with right now.

But it's not the answer, it's just gonna give you risk.

That's, and that's what I think I'm only learning is like I would just go,

go get a wolfie model on it, but no, no, that's not giving me the answer.

It's just determining the risk associated with the buildup that

I'm going to potentially look at.

Oh,

so it's telling you that there's a problem but not the solution?

Yeah.

So Cam, for example, is telling me at the moment this setup will have

a relative humidity of 81%, and this one, this setup will have a 90%.

So it's pick your poison kind of thing.

I just, I still don't understand what that kind of means either.

Like I'm, I, like, I'm only quoting what he said and it's like

practically, like you're trying to choose the lesser of the evils here.

Yeah.

Of your risk.

And it depends on how you'd identify a risk.

Is it a mold index of three?

Is that your risk?

Is your risk a mold index of five?

Like what do we, what do we,

yeah.

Can you maybe talk to a little bit about that, the humidity?

Like what, what, what are we, what are we deeming safe when, when we're looking at

this model and the, the results from it?

Yeah.

What are we deeming safe?

So essentially what deem, again that national construction

code deems acceptable is a mold growth index of three.

Yeah.

Which essentially it's a measure of how much, um, visible mold you can

see with the naked eye on a. One by one section of your studied area or

how much you can see by microscope.

'cause obviously how much you can see

of what though.

Of, of malt.

Of.

Of malt spores.

Yeah.

Okay.

But is there, is there a magical, uh, humidity number when you're looking at.

Uh, no, not necessarily.

It's not about the, the humidity that

the humidity gives moisture to say a cellulose material that could be trapped

by moisture, which then is gonna drive the chance of a dry rod or a mold.

Yeah.

So you look, you're looking at the risk of condensation within the Yes.

Yeah.

Yeah, yeah,

yeah.

Exactly.

Yeah.

And, and it probably, it differs 'cause it, you know, correct me if I'm wrong

and I could be, it's super technical.

Yeah.

So the humidity can change as it goes through layers.

Yeah.

Yep.

So then it might just get to a point where there's a problem.

Yeah.

Yep.

And is a mold index of three even safe?

That's it.

And our

reality, it probably all depends as well, like on the person, because some people

are much more susceptible to mold than,

so one of the options, I'll be here totally.

We've got a double brick house, we're gonna build a 90 mil frame in it.

One of the options we checked is like.

The most cost effective and easiest method tried and tested against the world is just

go spell spray close cell spray foam in.

Mm, and then you're blocking

any environmentally.

Just let's remove any of those questions because it's not a water blown agent.

And foam can be considered evil, and I'm not.

I just ignore that for a second.

But there was still a chance that it could go wrong.

So now we go, well, is that the best solution?

Mm.

And then you start to go, well, I don't want to be like we've

seen in the UK at the moment with all the, the, the foam issues.

And I know that's a separate issue in, in roofs and stuff, and I still have

a HIV and I go back to this, this risk profile is like, I, I don't want to

be left holding the can as the builder here, even though, so I can go to

the design team, they can specify it.

We can get the modeling done.

Mm-hmm.

It says we're safe, but the N CCC is like, well, a mold index of

three after how long like is it?

What if it's gonna get worse?

What if we tested, it's now three and then it's five.

Are we now in trouble?

And

also, and also, what if it's o Occupy issue?

Yeah.

I've got a HIV, I've done everything above the code.

And

then I'm still left holding the

clients for whatever reason.

Turn the HIV.

Yeah, exactly.

So the thing is, you left holding the, the bath water here, and you go,

well, what risk do I want to take?

The question I, I literally asked the question, am I best just

putting in glass wall with a frame and whacking some plasterboard

I'm building to the absolute code?

Because if you thought in the cord of law, if I, if they're like,

well, you introduced in Intelo.

Well, that's a different building material.

You kind of knew about this.

Why didn't you do?

No, you're also the expert too.

Yeah, I know.

This is the hard part.

Like you, so you lose, you lose either way now.

Yeah,

so you're trying to improve the efficiency of the building.

And it's a retrofits are the scariest building.

Like if you building news easy, like so simple retrofits

and we've got a lot of use.

That's what I

love.

Solving the problem though, like I think that's what it gets

most

exciting.

My,

I love

it.

Yeah.

And, and that's, uh, I often say like, people, well you need your A team

to work on, on retrofit buildings.

Yeah.

You need more than

your IT team.

You need, anyone can do like new build.

Yeah,

you need more than that.

You like you, I, I, I literally asked the question to our Hogwarts

builders group of 10 builders of like, what would you do here?

And there was vast different opinions and questions and more questions.

And the questions then lead to more questions and

Yeah.

Well, I think about the fact that we've got this group of

people that actually one can.

Offer advice to that group.

Like as I was reading through it, I was in the middle of cooking dinner,

so I couldn't really respond too much.

But, um, the fact that we've got this group of people who have experienced

stuff and they modeled stuff and they can put in some answers, like,

that didn't exist five years ago.

Yeah.

I, I just wanna just with, with the, uh, wolfie stuff, and again,

I kinda wanna just bring it back to Park Life for a second.

What are some of the things that you are kind of modeling, uh, using hydrothermal

analysis in a building like that?

Well, essentially we, we model deconstruction assembly.

Yep.

So obviously we, we, we put in the layers or you know,

whatever materials we're using.

And that's one.

Probably the first problem that we have in Athermal modeling using Wolf

is that we rely on, on a database Yeah.

Of of products which have specific characteristic in

terms of how they behave.

Yeah.

From a moisture point of view, from a terminal point of view.

Um, what is then installed might be different from what

every model as a product.

Yeah.

And therefore our result.

Will be different.

Yeah.

So that, that's the first,

and I'm sure that's not gonna happen at Park Life though.

Did you run

Wolfies at Park Life?

Yes.

Yeah.

What did you

run?

That's what, that's kind of what I was asking before.

Yeah.

So what we run essentially, uh, is, um, is the, the wall assembly, uh,

because we started from a rainscreen facade as our perfect ideal situation,

uh, obviously a costly, uh, exercise.

Uh, we then

pro climber just bought out a new rain screen system this week.

I think

I saw that.

Yeah.

Yep.

Bit

of a plug there.

Pro climber.

Pro climber plug.

Yep.

Yeah, yeah.

Um, we then, uh, move onto a, actually an insulated panel facade.

So think York Kingspan insulated facade or asking insulated f facade, like a bond

door kind of type.

Yep.

That's it.

Yep.

Uh.

From there, we, because we had our, our target for high naus ratings, we had some

insulation on the inside of that, uh, insulated facade with some hair gaps.

And then the, the internal lining, we identified that that internal

insulation could create problems.

'cause then, uh, depending on how much insulation there was, they.

Interface of the insulated panel could become cold and

therefore at risk of condensation.

So we run a few tests on, on how can we deal with, with that risk.

Is

that too much insulation on the inside of the air type barrier?

Well, the, the airtight barrier was one of the, uh, so where, where

do you put your air tide barrier?

Yeah.

This, yeah, yeah, yeah,

exactly.

So.

In theory, the, the insulated panel becomes your terminal

hair barrier, water barrier.

Everything is in, in that way.

This one?

Yeah.

Yeah.

Everything is there.

When we introduce insulation on the inside of that panel, then we introduce

the risk of condensation on the inside.

Face.

And that's

for, because that's a metal.

It's a metal, yeah.

Yeah.

So it's,

and that will condensate.

Yeah.

Yeah.

And is that moisture moving from inside out

in Yeah, inside out.

And

metal's got a zero perm too, so no water is gonna transfuse through that.

Yeah.

Yeah.

So then we tried products to stop, uh, vapor moving from inside to outside.

So, uh, an air barrier, a vapor barrier on the inside

from pro climber.

Yes.

Yep.

You can say that.

Um, as an option.

Sure that works.

Uh, still risk because it works in the model where we assume a

perfectly installing inte Yeah.

But a commercial builder installing perfectly, uh, intel layer.

Uh, they, yeah.

It's almost impossible, I will say.

Yeah.

Is

it

though?

No, it's not, but you know.

Yeah.

But I think, I think, you know, I've had, I've had a number of

these conversations with Lamb before, and I guess this is where.

People like us, or I'm not saying you or me, but just people like us in the

resi space who have done the airtight stuff forever and a day or for the

last five or six years could come in and help educate these builders.

Yep.

Like, I'd love to do that because then look at the impact we're having.

We're upskilling these people that are building effectively 60 homes at once.

Um,

I, I was a young kid getting into industry.

I would just become an airtight rap specialist.

Honestly, I thought you were about to say become a, a big scale.

No, but like, imagine developer because is easy to finish company.

Whenever you imagine this,

say you, you're a young kid.

Oh, want, I, I wanna get into the industry.

Might not do carpentry.

I'm just gonna be an airtight specialist.

Think it the amount of work you could get from that.

Yeah.

Yep, yep.

Like across resi, residential and commercial.

Like, there's just, it will be, it will be a job in 10 years.

So.

To, to, to bring it back to your home.

You didn't end up building the house that Matt, uh, set out to

build, but you built a little pod.

Yes.

Yeah.

Could you tell us a little bit I the process of, in the process

of, oh, well you're an owner builder, so it's a ongoing process.

What's the pod

for?

So,

well, the pod started as a, as a almost like, um, a granny flat if you want.

Yeah.

That was, uh, the, the initial thinking, uh, essentially a room

with a small kitchenette and a, in a, in a bathroom for, for us to have

it as a, as a study, but also for, uh, for when, uh, you know, we have.

People coming over Yeah.

And staying with us.

Yeah.

Um, 'cause we don't really have the space inside the main house.

So that's where we started.

Obviously budget it as there as well.

Yeah.

And now it's simply a room.

It's simply a 10 square meter Yeah.

Room, which is gonna be a study.

Uh, and perhaps like, you know, a playroom for the kids or something like that.

So very more you certifying

it.

No,

no,

I did model it in, uh, in the easy pH.

Yeah.

Uh, and um, obviously you guys know small buildings, small volumes,

extremely difficult to get to, uh, to pacify certification or, or level.

But we got to the, uh, the low energy.

Yeah, low energy.

That's

pretty good though.

Yeah.

But you've also retrofitted your existing house and you've got a brick veneer.

Yeah, we've done a little bit of work.

What have you, what, what have you done?

Knowing what you know, so there's probably good, just two parts here.

What have you done and now knowing what you know, what wouldn't have you done?

Huh?

So what we've done, the first thing that we done when we moved in, um, is we

blowing insulation into the wall cavities.

Mm-hmm.

Uh, we put, uh, new insulation into the roof space, uh, PV panels.

Uh, rainwater tank.

That's the first thing that we did, um, when we, when we moved in.

And would you do that again now?

So the reason I say if you are someone listening, wanna retrofit

your house, like are they the easiest go-tos that you would do?

Again?

Look, again, it comes back to budget.

Yeah, that's what we could afford.

And, and that was his team.

Would I do it again now knowing what I know?

I would probably go.

M maybe see if I can get a bigger loan and, and actually do it.

Do a bigger retrofit.

Yeah.

That looks at the whole house as a whole.

Yeah.

Because obviously, you know, we touched on before you start to introduce an

insulation into wall cavities, into roofs, you change the way the house,

uh, behaves and it can create problem.

Yeah.

Now I think that my house is.

Relatively leaky.

So you, even if we put in a little bit more insulation, it's

not, it doesn't create an issue.

And in fact, since then, you know, we have change, uh, built-in ropes

and so we pulled out plaster from on external, uh, walls and, you

know, there, there is no sign of, of mold or humidity or condensation.

So fairly safe, but.

Can you create problems?

Sure.

Yeah.

The reason I ask is like, because the reality is that is the situation

of most people is I want to improve the energy efficiency on my home.

I want, like, I don't have the budget to do much.

Like how, like where are you starting points?

Because it's, I, my advice is I don't

draft proofing.

Yeah,

draft

now, but then you get two air title.

Well, I, you know what I, I mean, I disagree.

Like if, if, if you are looking at the absolute bottom of the tree, lowest

hanging fruit, go to Bunnings, spend a couple hundred bucks, draft proofy windows

and doors, silly because I guarantee like you are losing so much air and I,

and I wouldn't think that you would get it that airtight that it's gonna be a

problem.

No, I agree.

And the other one I would start, go straight to is.

Get some external warnings over some windows.

Yep.

External warnings.

But I mean, I know this is probably not what we said.

It's talk about p PV and electrify your home and go to, uh, Cape Pump acs.

Yeah.

And then Oh yeah.

And, and the thing, as I think you've said before, a number of

times, like the electrification doesn't have to happen overnight.

Like, it just means as if you are, if you are dies one at a time.

Yep.

Change it to an electric.

The heat, if the gas hot water applies, change it to a heat pump.

Like

just do the, although Tim, although Tim Ey did say something else, he goes,

just fucking send it and just do it all.

But,

but I actually agree, but not everyone.

Sometimes we live in and I did and I did say that, I did that, say that to him.

Um, great conversation and I know we kind of went everywhere then.

Um.

We have a, uh, a segment on here called the MEGT Mindful Moment,

and today I want to kind of go back to a topic that we touched on

before and it's, um, apprentices remaining curious and curiosity.

We've talked about PHPP today.

We've talked about our star rating.

We've talked about wolfie.

Now wolfie, let's maybe kind of park that over here for a second,

but your, your STAR rating and your PHPP if you're building with a

high learning from high performance builder exists in pre-construction.

Ask your boss to have a look at it and ask your boss to talk you through it,

because that understanding of, of why we're doing something will then relate

to the practicalities of why you are so, the theory behind, you know, what you're

trying to achieve, and the practical side of installing a window, well,

really well insulating and wrapping and building well, like this is dictating

the outcome of what you're doing on site.

So just have that curiosity and just going and, and have a look at it.

Agree.

Rob, if you could change one thing in the whole building design community

world, what would you change?

Oh, you asshole.

I'm gonna, I'm gonna, I've got, I'm gonna start, I'm gonna start asking

some hard, I, I've got this idea of asking some really hard questions.

That last question now?

Yeah.

Yeah.

I wanna leave it on some spicy notes.

Yeah.

Well, one thing that I will change or.

Implement is mandatory hair tightness testing as part of your

building permit requirements.

Yeah.

And that's a good, and it's a good, easy low hanging fruit one.

And you know what?

Super cost effective 1500 bucks, uh, cheaper if you go through Drew.

Uh, but you know, like that is such a, from, from a client point of view,

from a builder's point of view, knowing what your air tightness is is massive.

Yeah.

I actually that's, I think that's a great one.

I think sometimes we try to get too technical with that answer and we

try to solve the world with one.

I think you, what I love there is you pick just one little

tiny component and gone for it.

So Rob, thank you.

Um, needing on to hit vhi, visit hit vhi.com.

Yeah.

Um, all kinds of ESD passive house, um, just really building up the

industry to do better things.

So thank you for so much for, for your time today.

We really appreciate it.

I, there's some things that I wanted to talk to you about,

which you didn't get a chance to.

Maybe that was maybe this next one.

Oh, just the, you know, the, the government funded buildings that

are coming out that you're working on and all that kind of stuff.

But maybe that's a topic.

Oh, that's

for another next time when maybe they've rolled out and you can actually

talk about it more because Sounds

good.

I'm super interested and excited, the fact that the government's

investing money in this stuff.

But Well, we have to.

No, we have

to.

That's like we have to, it's not, it's not like a don't take your hat off to them.

Like, well, we should, but like, we should be doing this.

We need

to, okay.

I know we're digressing this, we to do this.

I don't to wrap this up, but you like the, the government is championing

and fucking shouting from the highest building these big roads that we're

building, but they're not talking about these, these homes that we're building.

Yeah.

Anyway,

that's a great way to finish it.

Yeah.

Thank you guys.

Rob, thank you.

Thank you.