There are no immediate tax breaks for buying a home (such as a homebuyer credit) for cash but keep in mind that you are allowed a deduction for all property tax paid.
Home improvements would not be deductible unless they are qualified energy efficient
If you make improvements which increase your home’s market value and/or extend its useful life, you can add to the cost basis of your home, which may reduce the capital gain when you sell your property.
In addition, you may be able to deduct the sales tax paid for building materials for a major improvement to the home if you itemize deductions and choose the sales tax deduction over state income taxes paid.
See Home Improvements And Your Taxes