2121b1b5_re___AccountingExplanation_com__Reasons
[0] Building A/c is debited. [Sr. No.] (xiii) [Nature of Expenditure] Capital expenditure. [Reasons] 
This is an addition to a fixed asset and as a result of this expenditure the value of the building has increased, so it is a capital expenditure.
Difference between Capital Expenditure and Revenue Expenditure - AccountingExplanation.com
Reasons