For the most part modular homes are considered the same as traditional stick built homes. They are both permanent structures and will appreciate in value over time. There are some small differences in financing a modular home.
If possible you should first approach a mortgage company that has experience with modular homes. Otherwise you may encounter some headaches as the inexperienced mortgage company tries to catch up with and learn about modular homes. They may try to fit your modular homes project into one of their predesigned loan packages instead of having a proper matching loan package to start with.
As with buying traditional stick built buildings, modular homes can have a fixed interest rate or an adjustable interest rate for the life of the loan. It is also possible to finance a high percentage of the value (up to 95%) although it is not recommended. Once you are approved for a loan you can have a time frame of up to one year for construction to be completed. This is plenty of time since most modular construction only requires one to three months. Make sure you find an expert to help you with this process.