Want to lay peel and stick floor tile over hardwood floor planks in bathroom, but there are cracks between some of the planks, as they have been replaced. What would be best to fill them with?
The replaced wood is also unpainted. Should it be painted before putting down the tile?
Thanks for the help.

Sorry but you can't do what you describe. There is another post on the desk right after yours where I spelled out what to use and how to install a proper Hardiebacker sub floor. You too will also need to prime th sub floor with 2-3 coats of adhesive primer from the tile aisle at you home center.