Hallo,
If render and plaster is
he same, than what is meant with the problem of the air tightness in the passive
house. There was said that the air tightness was not so good because of the
failing render but then earth plaster was on it!
Greetings,
Carina
Von:
strawbale-bounces@amper....muni.cz
[mailto:strawbale-bounces@amper....muni.cz] Im
Auftrag von Andrew Morrison
Gesendet: Donnerstag, 21. April
2011 17:46
An: European
strawbale building discussions
Betreff: Re: [Strawbale] Air
tightness and earth plastering
As far as I know, they
are the same. Here in the United States we say plaster. When I was in Australia
teaching last month, they spoke of render. I don't know of a difference.
Andrew
2011/4/21 Carina Simons <carina.simons@gmx...>
Hallo to everybody,
Since I am not a native English speaker I do not
know the differents between a render and a plaster. Can anyone explain that to
me?
Many greetings,
Carina
Hello everybody,
Till yesterday I was pretty confident that it was possible to make a good air
tightness using earth plastering. Yesterday an other professional
called me regarding air tightness. His neighbor and him did a blowerdoor
test to verify the airtightness of their 2 passive houses (should be
passive). The result was not good. The n50 leakage rate
is supposed to be smaller than 0.6. The building must not leak more air than
0.6 times the house volume per hour (n50 ≤ 0.6 / hour) at 50Pa
(N/m²) as tested by a blower door.
He obtained n50 = 1.2 and it was 0.95 for the second one. They
worked 2 days trying to find what could be the problem and didn't find any
major leakage. There was 1 point that could be a problem. A
basement wall that is part of the living space get only 1 layer of earth
plastering but no render. The thickness is more or less 1.5cm. They
decided to glue a airtightness sheet (1 square meter) on this wall. They
blew the air outside of the building. Then they saw the sheet (that has
been glued) inflating meaning that the earth plastering was not airtight.
Of course, I have to say that it would be better to put the render on this
wall. Airtightness should be probably better.
I'm building a straw bale (this is our house) and we really want a good
airtightness. For the wall, the earth plastering is supposed to do the
airtightness. We are going to make a blower door test before finishing
the details. This means the renders are not ready yet because we will put
the last earth layer on the wall and ceiling at the same moment. This
will be done after the blowerdoor test. This means that the blower door
test will perhaps not be successful.
What do you think about it ?
Does anybody already make a blowerdoor test with earth plastering airtightness
?
I would really appreciate a feedback.
Many thanks
Cheers
Sebastien
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