XPS as external wall insulation

[hickory1992]

I have seen alot of people use XPS below damp course/basements/plinths but everywhere else seems to be EPS.

I had quite a bit of XPS left over from doing my garage floor and was looking to use it instead of EPS in external wall insulation.

I realise EPS is meant to be more breathable but for a single skin garage would it make much difference?

Would there be any downside of installing XPS externally on the garage and having it rendered.

 

[^woody^]

EPS is not more breathable, and no foamed insulation board is.

Either board is suitable for EWI and render, with XPS being a slightly better insulator for the same thickness