Monday, September 13, 2010

Building materials

One of the things I have most wanted to write about in this blog is selection of building materials. There are so many materials that go into building a new house. I'm sure I won't be able to list them all, but I'll try to cover the main ones, especially those I haven't talked about in other posts.

Our slab has a high proportion of recycled aggregate and uses Boral Envirocrete 60% Slag/Flyash with 100% recycled mesh. This is the kind of stuff that would never have occurred to me and probably wouldn't occur to anyone except a dedicated green builder. Score 1 to Positive Footprints. Creating markets for recycled products is a huge part of closing the loop. Given that about a third of waste in Victoria is construction waste, it's great to know that our slab is partly made of concrete that might otherwise have ended up in landfill.

The structural pine we are using is treated, but not with CCA. It's something else, but I have no idea what. :)

I have just been reading Linda Woodrow's permaculture book, and I've been chuffed to learn that plants really dislike the heat that radiates out of buildings that have a high amount of thermal mass on the outside. I can afford to be chuffed, because we have none! We chose lightweight cladding products for many reasons:
  • Radial sawn timber and Ecoply for their relatively low embodied energy
  • Zincalume for its zero maintenance, long life span and recyclability (in facilities that exist even now, not just in some hypothetical future).
I do love mud brick and strawbale, but the former was beyond our budget, and the sheer square metres taken up by the latter just wasn't going to work on a block of 363m2.

Wall insulation:

Tontine Thermal & Soundbatt R2.5; CSR Bradford Enviroseal Breather Foil. I particularly love the clauses in our specifications that say things like:
"Batts to fit snugly between framing members with no holes or missing sections. Batts not to be compressed. Any batts removed during construction to be replaced."
Maybe that language is standard in any building contract these days, but with our builders, I can feel totally confident that these provisions will be observed.

Ceiling insulation:
Tontine Insuloft R3.5; CSR Anticon 55mm (R1.5) foil backed blanket.

I also like the bit in our specification that says, "During construction the Builder is to limit any thermal bridging between inside and outside as far as is practical." (Thermal bridging is where heat from outside can get transferred in, or vice versa; aluminium window frames are the best example of these).

Our windows are from Mouldright. Crap name, beautiful windows:

All of our windows are double glazed, most have low E glass.

Almost all of our window frames use finger jointed hoop pine. Finger jointing is basically a way of creating incredibly strong joins between pieces of timber. It means you can make quite long pieces out of many shorter ones and so is a very good way of making trees go further. This was the most affordable timber option for us, but while I love finger jointing, the fact that it is hoop pine does represent a bit of a compromise for me.

Hoop pine is plantation grown. Lots of people might think this is preferable, but personally, I've walked through hoop pine 'forests' in Queensland, and I would prefer well managed, selective logging of native forests over a monoculture every time. Here's a nice article that gives some background to explain my preference:

External doors:
Also by Mouldright. Ours are made of recycled Karri. They're gorgeous.

Other timber:
We are using American off-cuts from another job for the timber nosing on our stairs. Our bannister will be recycled jarrah.

See my post of 16 August:

Colorbond, same qualitities as zincalume. We would have used zincalume, but didn't want to reflect that much sunlight into our (hypothetical) neighbours' eyes.

E0 wherever it is used.

E0 MDF is also being used in our stairs. I don't know if Jeremy found these folks on the basis of doing the right thing, or whether he worded them up. Either way, it's great to know that there are people out there doing stuff like stairs with VOCs and recycled materials in mind.

Plumbing stuff:
We've relied on WELS ratings here. We have installed a hot water diverter to reticulate the warming-up water, but apparently they can all be a little glitchy so they've been installed in ways that are easy to get in and fix. We haven't installed a first flush diverter on the rainwater tank, because Jeremy says he's never found one that really works.

Thanks to PF really caring about the little things as well as the big ones, we are using recycled crushed rock as bedding for our sewerage and stormwater pipes.

Modwood. See

Phew. That's all I can think of for now.

As I said in my last post, I'm running out of topics. I do want to post on the different options we had to choose from to boost our house's thermal performance. And I want to write about what this place is actually costing us. I was also thinking that I might go into the design side of things a little more. So that's three more posts!

But my statcounter seems to suggest people are actually reading this blog, so if any of you have questions or things you'd like me to write on, please let me know.

Thanks for reading.


Thursday, September 9, 2010

Deep Green Builders

A couple of things have happened recently to make me realise the incredibly important role that truly green builders play in building a sustainable home. So this blog is, in part, to tip me lid to our builders: Jeremy, Chi and Grant at Positive Footprints They are truly awesome.

I need to start off by acknowledging that:
  • there probably aren't enough green builders to go round, especially if you happen to live outside a major city and not in a place like Byron or Castlemaine
  • it's critically important that mainstream builders start to move towards even a very light shade of green if my son and his friends are going to have even the remotest chance of any kind of decent life on this planet, and
  • if builders were mandated to use the kinds of materials and approaches that we are using in our build, all buildings would be more or less sustainable and I wouldn't need to write this post (instead, I'd write one on closed loop water systems, or roof gardens, or going beyond 9 stars ...).
But with those caveats in mind, I would still always suggest if you can find someone who is really, properly green, go with them (unless of course they have a reputation for being dodgy or bodgy!).

If they're more expensive than the next gal, build a smaller house, save up for the solar panels later, or skip the polished concrete floor. That's what we've done, although in part that was to pay for our great indulgence: five round windows on our street facing side. (At this point in the build, our window makers must be wishing we'd chosen the solar panels)

We chose to build with PF because it seemed from the very beginning that we were on the same page. They, unlike most builders, had a deep understanding of our value statement, and even had a matching one of their own! The fact that we could afford them was a bonus! :)

We have never once regretted our decision. I reckon building with them - rather than building with a conventional builder - has probably halved the amount of research and thinking I've had to put into this build. It has meant that I have been able to focus on questions like the layout of the kitchen, rather than insulation and windows.

In our experience, having builders who start with a principled environmental stance means that:
  • they are incredibly well informed about current product options
  • they have a network of tradies who either work within the same building paradigm, or at least are willing to fit in with it on green jobs
  • they are willing to work with the 'green' expectations of clients, but also knowledgeable enough to challenge them (for example, we started out wanting a waterless loo; Jeremy convinced us there were far better ways to spend our money)
  • they will build everything with principles like low embodied energy in mind.

As I said at the beginning of my post, a couple of things have made me appreciate the importance of green builders all over again.

The first of these was last week, when we decided to get the builders to just bung in a cupboard rather than have it made by a cabinet maker. Jeremy said, "So we'll just get some E0 mdf for the doors". It was that easy. I love it that E0 is a given, not something I have to specifically request (over and over and over again).

The second was today, when I was sitting on the train writing my next post, on materials, in my head. (I'll put it up in a day or two). There have been so many aspects of the build that I sincerely doubt any but the most committed sustainable builder would think about. Put together, I suspect that our house will have - for a new dwelling - significantly less embodied energy than most other houses being built in suburban Australia today.

Of course, there are people building all kinds of wonderful places out of town, using all manner of building materials, but when it comes to building on small block in Preston, we simply couldn't have achieved anything like the ecological values that we're having if it hadn't have been for our green builder.

Just to finish up, I want to suggest the things I'd be looking for if I were starting my search for a green builder tomorrow. There is of course the Master Builders Association Green Builder certification, but for me, that would be the elementary qualification. I'd also be asking about:
  • Skills - is there good evidence that the builder really knows their stuff? Do you see evidence of attention to detail in the houses they have built? If there appear to be things that could have been done better, can they explain why they are as they are, and/or what they would do differently next time?
  • Knowledge - Can the builder talk knowledgeably about the range of products that is out there? For example, can s/he tell you what building materials are preferable in terms of their embodied energy? Do they seem to have a really strong attachment to one style of building or one product? (If it coincides with your interest, that might be a good thing, but if they feel they've found 'the best', it might be that they've stopped looking at alternatives)
  • values - what evidence is there that the builder really cares about environmental matters? For example, how has green building influenced how they live their own life? How sustainable is their own house?
  • Understanding - what evidence is there that the builder has thought about the complexity of issues that need to be considered in sustainable building. For example, what do they think of plantation versus logging native forests? From memory, I think Jeremy and I don't exactly see eye to eye on this, but he knows the issues, and that's what counts.
  • Networks - does the builder have a network of similarly minded and skilled tradies? How does s/he manage when tradies are not on the same page?

Okay, that's it for now. I'll post the materials blog next. After that, I will have exhausted most of the topics I wanted to write about when I started blogging. Am open to suggestions for future topics! Bring 'em on.


PS I just realised that I don't think I've said anywhere else that Positive Footprints also designed our house. More on that in a later post. :)

Saturday, September 4, 2010

Plans and elevations - finally

Okay, so I finally found time to clean up the plans and elevations so that they are fit for the general public to see. I just scrapped a lot of the technical stuff with a quick once-over with photoshop. Hopefully they're comprehensible. And hopefully, this works!