Need some ideas for partly walling off a 'lean to'

[Rollerball]

I have an outdoor 'lean to' that's basically a slightly sloping roof on six posts. It's about 7 feet high, 10 feet deep and 15 feet wide.

It's open on all four sides but I want to block off two of the sides up to a height of about 6 feet or so (well, one side and the back). I initially thought of using large sheets of wood but they are likely to be blown away when the wind catches them. I then thought of using planks of wood and nailing them horizontally above each other to build up the required 'walls'. Not sure how much the wood will cost though as I'll need quite a few treated planks!

I don't want to spend a fortune on this, so am looking for the cheapest possible option yet which will last for a few years. The lean to is in the corner of a large garden and it gets pretty windy there at times (although it's slightly sheltered on two sides by hedges).

Any ideas please over and above my suggestions above?

Thanks

 

[Deluks]

build the equiv of a featheredge and arris rail fence. They are usually pretty tough in a breeze.

 

[JohnD]

what do you want to put in it? Must it be clean. dry or draughtproof?