Tom The Great wrote:
...

Can tyvek be left exposed? Serious question, since vapor barriors on
insulation says they need to be covered with fire barrior. Just
thinking out loud, will look this up. Thank you!!!!!!!

tom

I just did a little search and found this from DuPont:

9. Can DuPontT Tyvek® be used in attics? On roofs? Under Floors? On the
interior?


In 2006 DuPont introduced Tyvek® AtticWrapT, a unique, breathable membrane
that helps create an airtight seal to reduce air leakage and energy loss
through the roof. All other DuPontT Tyvek® products in Canada and the US
have been tested and approved as a product to be installed behind exterior
walls.



--
Joseph Meehan

Dia 's Muire duit