The spectacular Drawing Room at Cragside, near Rothbury, is undergoing urgent work by the National Trust to save it from rainwater damage.
A colossal 6m tall fireplace, weighing around 10 tonnes, is the first area to be given attention to prevent it from crumbling.
It spans from floor to ceiling and was carved from a mixture of Italian marble and alabaster.
The work being done will stabilise the marble while the sources of the water getting into the building are being investigated further and repaired.
Cragside property curator Clara Woolford said that if left untreated the fireplace could crumble.
Conservators are working on the fireplace, though it could take years to fully dry out.
The National Trust is carrying out a detailed survey to identify where the water is getting into the building.
Clara continued: “The Victorian drainage system doesn’t support 21 st century weather conditions. Winters at Cragside are wetter and much longer, due to climate change. We are more prone to significant bursts of rain and stormy weather. The drainage system is now visibly overwhelmed by water which pours from the gutters and cascades down the outer wall.
"Additionally, any gaps in the masonry mortar joints or in the stonework itself will let water in and cause the problems.”
In addition, work is set to take place to repair the enormous chenille carpet in the room.
The conservation and repair of the fireplace and carpet has been made possible thanks to generous donations from the Wolfson Foundation, a grant from the government’s Culture Recovery Fund administered by Historic England, and support from a private donor.
Cragside was the home of Lord William and Lady Margaret Armstrong and the first house in the world to be lit by hydroelectricity. Lord Armstrong used water to power luxuries such as a passenger lift and hot-water plumbing.
His innovations attracted attention from high society and even a visit by the Prince of Wales – later Edward VII - and Princess Alexandra who were depicted in the Drawing Room in front of the spectacular fireplace.