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John: So what does it take to build
more airtight on your next project? Well,
if you're just wanting to build to meet
building codes,
it doesn't take much, but there are a few
big things
you should pay attention to. You use the
same techniques to make a
pretty good house into a top performer.
The design stage is the best time to
make
big gains in performance. At this point,
you're just
thinking in real rough terms. What's
inside,
and what's outside? You would think that
it would be
pretty obvious, but sometimes it's
actually not. To help you get the right
start,
let's do something really basic.
The Pen Test is something that anyone
with a pen can do
to help get a better performance for
their project.
Again, start with the simple things first.
Pick a point on your floor plan
that separates the inside from the
outside.
Like this wall around the lounge room.
Now,
trace your pen around where you think
the envelope is
without lifting it off the plan.
Obviously it follows the exterior walls,
but then what happens when you get to
this attached garage?
Is the garage inside or is it outside?
You don't want the fumes from the car
getting into your house, right?
You don't want to pay to keep the garage
heated or cooled,
right? So consider the garage totally
outside.
That means the insulation, and any air
sealing you do,
has to include that wall of the garage.
Make it simple, that wall is to the
outside,
And the door from the inside to the
garage, that has to be sealed,
just like any other door to the outside.
When you do a blower test, you'll see
that this garage door
leaks like crazy. Keep the garage outside
and seal it off from the house, keep
going with the Pen Test.
Soon you'll notice a few more of the
details.
What about all these plumbing services
on the wall with the garage?
Those are on the inside of the envelope.
Run your building wrap or air barrier
around this wall as if it was
outside. And this box for telecom
services,
that doesn't need to be inside run the
membrane behind this,
keep it outside and seal it where it
pokes through.
So that's how the Pen Test can very
simply,
help you plan where your membrane or
air barrier needs to be continuous, and
where your
air sealing efforts are going to be
most effective. Trust me. Keep it simple,
and you'll have no problem passing a
blower door test.
Decide what's inside, and decide what's
outside,
and then keep it straight and continuous.
The Pen Test is a powerful tool. Now, onto
a few more details.
I've mentioned an Air Barrier before.
What is that?
Well an air barrier system is all the
parts that go into
a seal between the inside and the
outside. That means it's not just the
exterior water resistant
barrier, it's all the other parts as well.
Think in basic terms again, the air
barrier system
is the floors, the external walls, and the
ceiling
on the roof of your building. Make this
into a
well-sealed system and provide good
ventilation.
Once this is done, all the other stuff
like your
attached garage, your porch, even your
roof,
those can be thought of as separate
things, that are attached
to your box. Air sealing a slab is
not a problem. The walls we've just
talked about,
and the ceilings, all sorts of things
poke through these elements
and they can have some major air leaks.
One last thing about basic air barrier
design.
Use simple materials to your advantage.
How about your kitchen cabinets? They're
usually
really bad, but for no good reason.
Often there is no plasterboard behind, or
above them.
Bugs or even rodents get in through gaps
around pipes and joints in cabinets.
That's because cabinets were never meant
to be
a part of the air barrier system, and
there's
no air barrier installed at those areas.
You can make one very easily.
But if you use simple and cheap
materials, like a bit of plasterboard
over the area, carefully stopped and
sealed,
before you place the cabinets, this turns
into
a non-issue again. It's really easy
if you think of it beforehand.
If you take an approach like this, think
of the big things first.
Outline very clearly, what's inside
and what's outside. You'll have a really
easy time
getting a respectable air tightness test
result,
and you'll be well on your way to
Build Tight and Ventilate Right. The
future
of residential building in Australia
will be strongly influenced by
consumer demand for energy efficiency,
comfort, climate resilience and quality.
Both the Building Codes Board and
Australian Governments,
are committed to the COAG trajectory for
low energy buildings, and this will
affect building regulations including
the NCC.
Builders will be expected to place
increased
emphasis on meeting and proving energy
efficiency compliance.
You'll be asked more and more, to
understand
and deliver both code compliance and
long-term building health and
performance. You will need to
Build Tight and Ventilate Right.
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