Part or all of the problem may be that the smell has soaked into the wood. You should always clean with a product just for animal urine like natures miracle or the sorts. If she has been doing this for a long long time, you may to contact a professional to clean that area.
She may be smelling her urine there, therefore thinking if she can smell it she can go there.

I would start to potty train her just like you would a puppy. Go outside with her, give her a potty command (ex. i say "go potty") make sure she goes & praise!
If she only does thins at night, maybe limit her water intake a bit but only if your house stays cool.
Or keep her in her crate w/ water.

If it just one spot in specific you can try to deter her by placing a piece of furniture there, her bed or her food &/or water dish there.

I don't have much time now, hope that helps a bit!