Waterproof previously varnished wood
Click on the image to open

I have a wood framed sofa that I want to move outside. It is varnished but I want to make sure that it can withstand the elements on my veranda. What’s the best thing for me to do? Put a polyurethane on top, or a mixture of linseed oil/Polyurethane/turpentine over vanished wood? Thanks in advance.