Waterproofing/ Roof on Pop-up blind

I have pop-up blind I'd like to use for turkeys in the rain, just set up in a field with some decoys on nasty days. But its not waterproof, so I'm looking to spray some waterproofing on the roof and maybe throw a tarp on the inside. Anyone else do this or any suggestions? Does not need to be perfect, I'll still rock a rain jacket I just don't want to be soaked and it constantly dripping.