Deduction u/s 54

I  thinks  its  construction of  property  within period of 3 years  form the date of  transfer / sale of   property  , it means you have start  construction  only after  the sale . please confirm with others also . 

Deduction is allowed in your case even if the construction is started before selling of any property.

Within a period of one year before or two years after the date of transfer of old house, the taxpayer should acquire another residential house or should construct a residential house within a period of three years from the date of transfer of the old house.