Weatherproof fabric?

Question

building a pergola about 4m x 4m it is not square shaped bit of a weird shape really but will look good. would like to add a cover to it in case of bad weather, something which can be pulled back and forth really easily. any ideas how to do this and where to get the fabric from?

Answer 1

Bradshaws Tarpaulins will supply one to the size you need. (on the net).

Answer 2

Boat building shops, tent like fabric