We are considering laminate floors for out entire first floor. We have large pets and were wondering if "accicents" or spills will penetrate the seams of the floating floor.

Depends. How much do the "accidents" happen?

What I would suggest is that if you do have this put in, do not buy the cheaper lower qaulity laminate. Yes - seems can be affected by moisture. Now that I have said that, you do have some options.

Have you considered a wood flooring product that can have a finish applied to it? That will help with moisture problems getting into the cracks and general resistance. Laminate will have more problems with moisture in most situations.

If your piddle problem is infrequent - just choose a higher qaulity laminate or bamboo.

Cork is an option as well. It can been finished after installed as well.