Morgan Sindall will restart working on the University of Nottingham laboratory building which was destroyed by fire in the new year.
The September blaze ravaged the partially-built GlaxoSmithKline Carbon Neutral Laboratory for Sustainable Chemistry.
The £20M building will be rebuilt to the same design and is scheduled to open in early 2016.
A spokesman for the University of Nottingham said: “We can confirm that our contractor has been working on the Jubilee Campus for a couple of weeks to clear the fire debris from the site where the fire took place in September in preparation for rebuild work.
“We are currently planning rebuild activity and will be making an announcement shortly as to when this will commence. The rebuild planning is based on the same design principles and construction materials to deliver a carbon-neutral sustainable chemistry laboratory building.”
The Health and Safety Executive is still investigating the cause of the fire.
Morgan Sindall warned that the fire would impact on its results for 2014.