By 
The property you are considering buying has the potential to generate a great deal of money. You only have one major problem, and this problem is the reason why you can buy this property at such a cheap price. The problem is the smell, the smell that a lot of pets leave behind.
Should I seal or paint floors and walls to trap odors? Will that solve the problem for you? Unfortunately, the answer is no.
Sealants are meant to block stains on the walls so they won’t leak and stain the new paint applied to the wall. They are not designed to seal or block gases (odors) from escaping or passing through. Some, but not most, paints produce a continuous membrane finish that is not permeable to gases. However, keep in mind that only one of the many sides of an object is being painted, such as a drywall or floor, this approach offers limited odor control and is successful.
Both fire and tobacco smoke are exceptions. But even long-term contamination of walls and ceilings with tobacco smoke can be sealed only after most tobacco tars have been washed with trisodium phosphate (TSP). The remaining tobacco smoke odor can be removed with chlorine dioxide gas. It is a small package of powders that when exposed to water vapor, produces a gas called chlorine dioxide. This gas oxidizes smoke residues and completely eliminates the odor in as little as 24 to 48 hours.
Sealing urine odors to the floor can work on plywood floors, but a careful analysis of the process reveals some serious flaws. Actually sealing laminate flooring reduces the amount of water and water vapor that reaches the urea salt (produced by urine waste) so that the salt does not produce the odor in the form of mercaptan gas.
However, when the floor is put back into service, small surface movements caused by occupant traffic and furniture will cause the sealants to crack and leak water vapor and escape mercaptan gas. The cracks are large enough to allow water vapor and mercaptan gas to escape, but too small to allow mercaptan gas and liquid water to enter to work with the urea salt. Also, the floorboards have six sides. Sealing one side is not enough to fix the problem.
Using sealants or paint to seal concrete floors is most effective, but most sealants and paints are gas-permeable. Also, scratches and wear spots on the sealant or paint will cause the mercaptan gas to flow back through the seal, creating the problem mentioned above.
Heavily contaminated wood and concrete floors present another problem. When urea salt gets wet from water drawn from wood or concrete, it expands and lifts sealers and paint off the floor. When these blisters burst, the smell returns.
So if sealing and painting don’t work, what works?