Pecanfan wrote:
It says on the side of Wickes expanding polyurethane foam that, if used
externally, it should be covered (with filler or mortar) within 7 days since
it's not UV resistant.

Anyone have any experience of exactly *what* happens to this foam if it's
not covered within 7 days?

I've just braved the elements for 3 days moving an external door - the new
door is finally vaguely weatherproof (with a combination of expanding foam
and frame sealant) but I really can't be arsed rendering & painting around
it before the spring. Am I being foolish? If so, as a temporary measure,
could I just paint the foam with some form oil-based primer?


The foam will initially darken in colour. In a few weeks, it will have
hardened considerably, losing much of its flexibility. In a few months
it will start to break up. A couple of years and it will be gone.

Painting it with a couple of coats of primer will stop this, but will
make it difficult to render later.


--
Grunff