Can I get a tax deduction for waterproofing my basement and adding 2 bedrooms there

It depends.  If this is your personal main home and it is not used for business as a self employed individual or for residential rental purposes there is nothing to deduct for these improvements. Capital improvement costs continue to add to the cost or your home or second home until you sell the property, at which time you will determine the gain on the sale, using the combined cost against selling price.  

If this is not your main home, and is not used for personal or business purposes, it may be considered investment property which would result in the same tax situation as above.