[Strawbale] Plaster content

Enn Veesalu enn.veesalu at hariduskeskus...
Thu Aug 11 06:00:38 CEST 2011

Hello Tomas!


Maybe too late for you, but you asked about recipe for lime plaster outside.

I am not sure for strawbale walls, but for stone walls (I hope it's the
same) restorers use ratio 1 : 1, what mean that 50% sand and 50% lime. 

Now days surrounding air have a lot pollutants and pure lime plaster is not
so strong enough for active components in outside. In this case is
permissible today to add very small amount cement too; for strengthening



Enn Veesalu




From: strawbale-bounces at amper....muni.cz
[mailto:strawbale-bounces at amper....muni.cz] On Behalf Of Thomas Simkevicius
Sent: Wednesday, July 20, 2011 12:01 AM
To: strawbale at amper....muni.cz
Subject: [Strawbale] Plaster content




Last week put some scratch coat onto my strawbale garage. The render mix
that I have used for the inside was 4 parts coarse sand to 1 part pure clay
to 0,5 part chopped straw. With this mix everything went perfect,  no cracks
appeared when the plaster dried.

 For the outside scratch coat I used the same ratio plus added hydrated lime
in powder to the mix. The ratio of the lime I tried to keep to around 5% of
the mix. The outside plaster cracked a lot. I'm sure that the reason for the
cracks was lime. There was little area outside where I did not put lime in
the plaster, and in this area no cracks appeared when the plaster dried.
What ratio of lime should I keep in the mix for the outside?






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