Interest on a construction loan is deductible as long as the construction loan is converted to a mortgage when the home is finished AND the home is finished in 2 years or less from when the construction loan was taken out. You can enter the interest (assuming you know it from your statements) as a "mortgage not on a 1098". You would enter the name of the lender and click the box for "I did not get a 1098 for this loan."