Since you have used the cash to make payment to the builder by cheque, the money has anyway entered in the banking system. So all you need to do is file your return disclosing the capital gains based on Rs 8 Lakh sale value (or Rs 8 + 3 = Rs 11 Lakhs if that's what you received) and use the capital gains for construction. The house should be constructed within 3 years of selling the land. Effectively, using all the gains for construction avoids all the capital gains taxes so nothing to worry here. For more details you can call me through the Taxfull website and have a quick discussion. Also you can find me on linkedin amitnarula.