Quote Originally Posted by bighit View Post
I used to lag duct work in building to kill the noise (not as loud as an airgun shooting through it mind you)

we used glass wool that had a ali foil on the outside .

like this http://www.rock-wool-insulation.com/...s-blanket.html
Thats a great tip, I'll follow that up, will be dead easy to wrap it in that then some roof felt over the top, thank you ld grin: