Can I tell the difference between a Modular Home and one constructed onsite?

You can't unless you see the house being constructed. There are no telltale seams, beams or lines, unless the builder used antiquated techniques. Modular builders use the same materials and used when constructing a site built home. When a home is completed you cannot distinguish between the two.Aren't the walls and materials lower quality? Absolutely not. Modular homes are constructed with 2x6 walls, and stronger materials so that the home can tolerate the rigors of being transported hundreds of miles. Most modular home factories use national brand name products to further enhance the quality of the finished product.