sanctuary magazine issue 12 - ask our experts - green home feature article
TRANSCRIPT
8/9/2019 Sanctuary magazine issue 12 - Ask Our Experts - green home feature article
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SANCTUARY96
Ask OurExperts
Our house heats up quickly in summer and we are wondering if we can
add thermal mass to the inside of our house to stabilise the temperature?
We wanted to get hardwood flooring but should we tile instead? I’m
worried tiles will be cold underfoot in bedrooms in winter, and I hate
cleaning grout! What should we use on the walls, especially if we decide
to use timber on the floor? Tiles? Stacked stone? Is there a special type of
thermal plasterboard? — Christie
Dick — You could add thermal mass (TM) to either the floor or the
walls, or both. Be aware that replacing the floor will probably be very
disruptive. You can add TM to strategic walls by installing rammed earth
infill between studs. The foundations of the selected walls need to be
checked – the key is to have a continuous foundation wall or a strong
bearer. Soil from your own site is best; sandy loam or sand will need 5
per cent cement. This is tamped solid between sliding strong forms in
150mm layers. This can be exposed as a feature (funky) or covered with
meshed render (smooth). You can also use conventional TM l ike bricks.
The structural issues are the same, but you might replace the whole wall
rather than adding to the existing frame. [Ed note: There is an interesting
discussion regarding Phase Change Plasterboard on the ATA forum:
www.ata.org.au/forums. Search for “Phase Change Materials”.]
My partner and I are building a house which will have extensive timber
decking. We are concerned about termite attack. We are both reluctant
to spray poisons. We understand that if we incorporate blue metal as a
base to the decking that this may provide a barrier. Can you confirm or
otherwise provide us with s ome eco-friendly alternatives. — Jane
Dick — Blue metal is not a barrier to termites. Crushed granite, as found
in Granitgard, is. It must be installed in particular ways by an accredited
installer and will give excellent non-toxic performance, if you keep the
maintenance up to the post bases. You could also use a resistant speciesor treated timber post in-ground, but you need to satisfy yourself of the
exposure risk to treated timber. Class 1 durability timber for in-ground
use avoids the treatment issue, but sustainable suppliers are hard to
find. Try The Woodage in NSW. Class 1 for above-ground use with
galvanised steel post bases is yet another option. But then you need to
consider whether you need the in-ground cantilever effect to contribute
to bracing, or if you can provide that above ground... All good fun to work
out!
I have built a north-facing house with substantial standard glass to the
north including clerestory windows which allow the winter sun onto our
concrete floor. The only catch is that we are actually finding the sun so
glary that if it wasn’t for our beautiful view it would be tempting to put
our blinds partially down, even in winter. Is there a way to retrofit tinting
or similar onto the clerestory windows to reduce this glare and summer
heat and ideally reduce heat loss in winter as well? — Jenni
Lance — You can retrofit tinting to any window. Providing there is
nothing rubbing on the glass and the window is accessible right to each
edge, there should be no problems. There are many new-style selective
films available – one of the best is V-Kool ( www.v-kool.com.au).
Can you give me some advice on the difference between evacuated tube
and flat panels in the generation of hot water? Which ones are the most
efficient and cost effective? — Grahame
Lance — They are actually fairly similar in price and efficiency. The
evacuated tube collectors are considered to be a bit more efficient in
colder, cloudy weather, but there are very few evac tube systems available
in close coupled format (ie, with the tank mounted on the roof above the
panels): they are virtually all split systems. These have the panels on the
roof and the tank on the ground, and use a pump and pump controller to
circulate the water. Due to the added complexity, these are more prone
to failure than a close coupled system, which has no pump and works
on thermosyphoning alone. My personal preference is a close coupled
system, so I would install a flat plate system with either a stainless steel
tank or an all-copper tank (which usually work at a reduced pressure).
For boosting, the best option is a high efficiency instantaneous gas unit
such as a Rinnai S series solar booster or a Bosch 26eco+.
Your design, product and specification questions answered by our expert
columnists Dick Clarke and Lance Turner.
Dick is principal of Envirotecture, a sustainable building design firm
in Sydney. Lance is the ATA’s technical editor and a columnist in
Sanctuary’s sister magazine, ReNew.
Email Ask the Experts at [email protected]