Felt or membrane?

[vw754]

I need to cover my roof on my pergola that I've built , has a wooden roof , can I just put felt on it and nail it down or membrane.....not sure if it's same stuff , it's 14 feet x 9 feet so I'm thinking if I get a 15m x 1 m that should be enough to do it all.
Any advice please.

 

[Wayners]

Felt.
Maybe stick down Vs nail although you will need a few nails along join and edges

 

[vw754]

Felt.
Maybe stick down Vs nail although you will need a few nails along join and edges

Thank you