ITV Studios announced the investment in Leeds' Kirkstall Road facility last December. It said at the time that the investment was "about safeguarding the future of Emmerdale".
The Yorkshire Post reports that work will be completed by next spring. Outside scenes will continue to be filmed in the purpose-built village near Leeds.
"When the show started, there was three episodes a week, but now there are six a week and it's become a great success story which is why we're investing £5m in the future of the programme," said Adrian Bleasdale, who is project managing the construction.
"It's about creating the best possible environment to produce Emmerdale and we have worked incredibly closely with the production team in the whole process so that what we are creating here meets their needs."
He confirmed that the work will include custom-built studios for sets including the Woolpack and Home Farm. A sixth studio will also be designed for hospital and prison scenes.
However, despite the massive operation, Bleasdale said he hopes that viewers will not notice any mistakes when the sets are changed.
"Some of the sets will get moved, but we are duplicating as much as possible," he said.