"a loan for the purpose of purchasing a swimming pool,
Is this swimming pool part of the dwelling or something that will move with the owners if they sale the home? If it goes with the borrowers, this is not home improvement anymore than a car, appliance, etc. If it is a permanent attachment, it is HMDA reportable.
a loan to construct a garage,
Report as home improvement for HMDA.
a loan to make improvements to a barn.
Report as home improvement for HMDA.