Regarding deduction in 80C for principal payment of loan in case of construction of house property

1. Principal repaid will be allowed in the year of payment. The condition specified u/s 80C(2)(xviii), is that payment should have been made during the year and property should not be sold for a period of 5 years from the date of possession. 
2. In your case, the principal portion should have been paid during the year and it should be for the purpose of construction of house property. On satisfying of both these conditions sec 80C deductions will be allowed to a maximum of Rs. 1.5 lakhs during the year. 
Please correct me if the above solution has an alternative view. 

Whenever the principal is paid. Year of payment.