My wife and I have been looking at homes and we walked through 2 modular homes. In one we noticed a definite chemical smell, like an epoxy... some type of glue perhaps and the home was 4 years old. In the other house (2 years old) my wife noticed a different chemical type smell but I didn't think it smelled the same. I'm not sure if it was something that the owners created or not but I understand that some glue is used in the building process. Is this smell something common with modular homes or was it just the 2 homes we looked at?

Are you talking Modular or mobile?
Most modern modular homes are built with the same materials as site built homes. There are adhesives used in both. For things like tile etc.