exemption u/s 54

i had sold my residential house for 20 lakh and i there are capital gain of 12 lakh now i invest 7 lakh in new residential plot and after that i have incurred too much on construction of residential house on that plot .

my question is whether that construction amount is available for exemption u/54 in addition to 7 lakh?

yes. you are eligible for benefit under section 54 for 7 lakhs plus construction cost

Yes under sec 54 construction time is allowed for exemption.

Also you have 3 years time for construction from the date of transfer of residential house.