I am going to refinish our hardwood floor. I need a covering which is very durable as we live at the lake and have three dogs. I have a satin finish on the floor now and find that it is not very durable. What is the most durable surface that I can apply myself? I am from Canada so this must be a product that is available here. Also, the floor has cracks or spaces beteween the boards and I need to fill these. When the floor was originally done the installer used a sand sealer, he put something allover the floor which filled in the cracks then when it was dry he sanded it off. I need to know what to buy in order to repeat this process as some of it has lifted out of the floor. Thank you for our help.