The cost of improvements to a house is a legitimate itemized deduction,
to the extent that it exceeds the 10% or 7.5% floor for medical
expenses, depending on your age.
To determine the value of your house before the improvements began, you can contact your local property appraisal district (if you have one) that sets the appraised vale for your property for purposes of taxation. This information is often available online, or a local real estate agent can help you.
As for the value of your house after the improvements, the IRS has ruled that certain improvements, such as
installing railings, support bars, changing counters and cabinets, and other modifications in the bathroom for a disabled person by definition
do not increase the value of the home - this makes your appraised value
after the improvements the same as before them.
