Varnishing floorboards

[jakesi]

I have varnished floorborads but the varnish is wearing and peeling in some places. Is it OK to varnish straight over the top with another coat of varnish?

[snick]

It's just like paint really. You need to thoroughly sand down the peeling bits, right back to the wood and then apply at least three coats of a resin, not water-based varnish, or more if need be to match the rest of the boards.