You will recall that the external Theca panels were installed with a set of battens running horizontally across them:
These battens were attached to the vertical studs that are part of the panel itself. (These studs are quite handy in that they create compartments in the panel so that insulation is evenly spread and does not accumulate in one area and leave “air gaps” in others) Gib is attached to the battens and as there are no studs in the traditional sense directly behind the Gib, we had to think through where any very heavy items, such as curtain poles or bathroom basins, would be attached so that we could add extra horizontal battens before the Gib is attached. (This isn’t necessary for hanging art work).
All electrical pre-wiring is run, with cables and wires going between the battens and the Intello membrane so that no holes are made in the airtight layer. Home entertainment and data wiring has been run the same, plumbing fittings have been installed, and the ducting for the ventilation system installed.
Some of the wiring and plumbing is almost a work of craftsmanship and art, and I have joked a few times about leaving it exposed, Centre Pompidou style, as a talking point!
When I saw the pipes being lagged I did wonder why that was needed when there is zero chance of them freezing in this warm house. So I asked Glenn Murdoch and he explained that the lagging is required for two reasons; the first is the waste pipes are those being insulated with wool because waste pipes, especially soil stacks (the fat vertical waste pipes) have outdoor air in them so are a source of heat loss. Even the smaller ones are exposed to outdoor air from the bottom end. The second reason relates to the water supply pipes which get insulated with black foam because we want to ensure that the furthest taps have water as hot as possible at the tap and that cold water pipes remain ground-temperature cold and is not warmed up by the house being so warm! PHPP takes into account heat gains (and primary energy consumed) due to heat losses from hot water supppy pipes and the hot water system in general. Clever, eh?!
We have spent a lot of time poring over the plans, thinking through how we will use the house, and trying to pre-empt all decisions down the track. even so, we have still had to change our minds or revisit some earlier decisions. By making these changes now, although sometimes there is a small re-work cost, it is substantially cheaper than making the changes later. Building in the passive method does not mean that we can’t make alterations later on, it’s just that all alterations need to be considered in terms of the airtight membrane and retaining its integrity or repairing it in an adequate manner.
I have to say, I have found a certain reassurance in making these decisions up front and being so well organised and decided on what fittings we would have, where switches and sockets will go etc. It’s also a bonus that it helps to control the budget somewhat! Even so, slight modifications have been able to be made as our plumber entertainment system guy and electrician each walked us through the house to decide the final location of each and every specified item. Through this process I learned that I had been over-optimistic in the size of one bathroom and I downsized the basin to fit the space better, and we also spent time sitting or walking around the various rooms visualising how we will live here and this helped us realise better locations for sockets, switches and the TVs.
This has been a huge advantage of working with a quality building firm and two company owners (Guy and Pete) who work collaboratively with the us to ensure we get what we are dreaming of (or sometimes, what we don’t know we are dreaming of until presented with it as an option!). Their relationship with the sub-trades is such that discussion and suggestion is encouraged, and the “subbies” are of a high quality with knowledge and experience to ensure that no assumptions are made and they have provided me with lots of information that I didn’t know I needed to know! For example, Andy, the plumber, made suggestions on location of shower mixers that will prevent me from drenching myself each time I turn on the shower. We have never built before, and it’s those little things that we didn’t know we needed to think about that will result in us having a fabulous result and many happy years in this house.