Getting the right fabric

[EATmum]

Please can I call upon the collective MN experience? I've had a mad idea to make a patchwork picnic blanket for a friend's birthday, and it looks pretty if a bit ramshackle so far. But I want to include a fabric on the back to hold it all together that is lightweight but sturdy and reasonably water-resistant. Everything I'm coming across is either very heavy or very PVC-type - nothing seems quite right yet.

I had the idea tonight that maybe I should use interfacing to make it all a bit more sturdy, as well as the backing fabric. Is that just random? I know it wouldn't help with the waterproofing, but I was wondering if it might help the fabric stay firm?

Ideas please ...? I'm so new to all this, and very much learning as I go. Thank you!

You can buy a fairly fine and fluid waterproof fabric on ebay.

Don't know about the interfacing, I doubt I'd do that, but depending on what fabric you've made the patchwork in, I might use wadding to make it thicker and more comfy?

May be a bit random, but what about shower curtain material - the softer kind that isn't pvc. That way it would be washable and water resistant. My only other suggestion is to go with a polar fleece backing which would be lighter but not waterproof.

Thanks for the ideas - will investigate shower curtains, certainly hadn't thought of that...

I think if it was me I might try to get some waxy fabric - not quite oilcloth but like they make waxed jackets from? Is that the sort of thing.?

I have some stiff gingham that would do the job.