Wickremesinghe told CNN in an interview that much of its contents from his torched residence were not salvageable.
“I have lost more than 4,000 books, including some that were centuries old,” he said.
A 125-year-old piano was also destroyed in the fire, he said.
A video released by Daily Mirror newspaper on Twitter on 10 July showed grim visuals of Wickremesinghe's charred residence and a damaged sedan among others.
Will Not Allow Another Govt Building to be Occupied By Protesters: Wickremesinghe
Paintings and artworks were strewn across the house and the compound.
Wickremesinghe said he respects the rights of the protesters to peacefully undertake their demonstrations, but he asserted that he will not allow another government building like the Presidential Palace or the Prime Minister's private residence to be occupied.
The acting President said he has authorised Sri Lanka's armed forces and the police to take whatever action is necessary to stop people from storming public facilities and obstructing Parliament. "Don't obstruct the parliamentarians and the parliament from carrying out their duty," he said in the interview.
"We are trying to prevent (the police and military) from using weapons…They have been attacked on some occasions, but we still told them that they should try their best not to use weapons,” he added.