Probably not, although she might have a claim against you for unjust enrichment.  This is where one individual confers a benefit on the other one such that it would be unjust not to require the other one to compensate her for that benefit.  More would need to be known such as how much she spent, how much it added to the home's value, how much the mortgage payments were, etc...  If you two are amicable, it's probably best that you come to some agreement on what seems fair.