While computing income chargeable to tax under the head "Income from house property" in case of a let-out property, the taxpayer can claim deduction under section 24(b) on account of interest on loan taken for the purpose of purchase, construction, repair, renewal or reconstruction of the property.
Deduction on account of interest is classified in two forms, viz., interest pertaining to pre-construction period and interest pertaining to post-construction period
Post-construction period interest is the interest pertaining to the relevant year (i.e., the year for which income is being computed).
Pre-construction period is the period commencing from the date of borrowing of loan and ends on earlier of the following:
➣ Date of repayment of loan; or
➣ 31st March immediately prior to the date of completion of the construction/acquisition of the property.
Interest pertaining to pre-construction period is allowed as deduction in five equal annual instalments, commencing from the year in which the house property is acquired or constructed.
Thus, total deduction available to the taxpayer under section 24(b) on account of interest will be 1/5th of interest pertaining to pre-construction period (if any) + Interest pertaining to post construction period (if any).
Source:- Income tax website.