We are replacing carpet with laminate over concrete. The carpet has pet urine areas. The offending pet is still in the house. Should the concrete be sealed with something before laying the laminate?
If you are putting laminate flooring down on concrete you should use a subfloor panel, such as a Dricore engineered subfloor panel. These raise the floor up and allow air to flow below the laminate. It will also keep you warmer.
This is crucial in your application. This will prevent moisture in the concrete from ruining your subfloor and allows your concrete to breath, and may allow evaporation of any moisture from urine (but... you need to get that urine quick. If it sits on the floor, it will go through the cracks - no matter how small - and eventually lift/warp the flooring, even with subfloor.)
Let me be clear - do not put wood on concrete. It will always be giving off moisture. If you do not want to buy subfloor, use at least a 4mil thick vapor barrier liner. If you don't catch urine on the floor with 4mil VBL, think - it will just sit there trapped by the vapor barrier.