If I want to paint the out side of my house flat and plastered, with a new
coat of paint , and the paint does not appear dirty, and there is no mould /
green growth on the wall or flaky/dusty spots, how should I best prepare
the wall prior to painting.
Then what is the best method used, roller? with under coat then over coats
(how many) ?

Thanks

ci wrote:
If I want to paint the out side of my house flat and plastered, with
a new coat of paint , and the paint does not appear dirty, and there
is no mould / green growth on the wall or flaky/dusty spots, how
should I best prepare the wall prior to painting.
Then what is the best method used, roller? with under coat then over
coats (how many) ?

Thanks

Dust it off and paint it.

I'd use a roller, and don't use undercoat at all, use masonry paint, it's
what it's for, oil paint tends to seal it and stop it breathing, more to the
point, it stops any water behind from evaporating naturally, masonry paint
doesn't do this.