There are no set standards for either one. Two racing lofts can be entirely different, depending upon what works best for the owner. My search for plans on the Internet produced a few copies of loft plans donated by enthusiasts who had designed their own loft. My library search gave a general description with some guidelines. Once you have decided where your loft will be located, how many birds you will house and the amount of money you will invest in this housing, it's time to look at other lofts.
Pigeon fanciers are generally a group who try very hard to maintain a low profile.
Very seldom will you see a pigeon loft from your car window as you drive down a road. In order to investigate a loft, you need to seek out the people who own pigeons. Now is the time to get acquainted with the people you met at those meetings. Seek them out and ask them if you can see their lofts. Most pigeon fanciers have designed their own structures.