Husband and wife,both can be registered owner of a single house property - flat or house. Both can be co applicant and co borrower of house building loan - you can contact any bank who will vouch for this. Moreover if both are owner and husband takes a loan from a institution against mortgage and wife can take loan from any other person without mortgage then also she will be eligible for claiming interest upto Rs. 1,50,000 in her individual capacity. For deduction of repayment of principal, loan must be taken from an approved financial institutions/bank but for getting deduction under section 24 on repayment of interest there is no such restriction. If your office co-operatives sanction and give you a loan for buying flat, interest on that loan also can be claimed. Please let me know your confusion or disagreement, if any.