in ways to build an affordable rain roof / vestibule over a doorway, I found this recently.
Here is a video from a person who developed a very inventive way to make cattle panel shed.
this is part 2 of 2 videos. part one shows how he did the construction.
A good idea for affordable shed/vestibule, which can be covered with a more water proof top covering than this man did.
He came up with a really good plan. though. and for just over $100 for a four-foot wide shed.
add some knee wall to make it taller to go over the doorway.
when I build one of these, I will use 6ml 4 year infrared, anti drip greenhouse film. over the top.
anti drip keeps dew/condensation from building up and dripping on you =)
this film can be found online. www.amleonard has a page for poly remnants
which may have a smaller piece for such a project.
yes, I think rock wool is also sometimes referred to as mineral wool. it is made from waste from the
As you mentioned, even though rock wool does cost a bit more than fiberglass, etc.
it is so much better than those choices.
Roxul also makes products for exterior rain screens, etc. which I have not researched yet.
Radiant barrier. and dead air space are two considerations.
having used reflectix and armafoil. I prefer armafoil with micro perforations. this allows the breathability
and to not hold moisture up a against a wall.
creating a dead air space if you can certainly helps.