(CNN) Meghan and Harry, the Duke and Duchess of Sussex, spent £2.4 million (about $3 million) of British taxpayers' money on renovations to their new home, according to the Royal Household's latest annual financial statement.

The couple's official residence, Frogmore Cottage, which is nestled in a corner of the Windsor Estate, west of London, has undergone extensive structural changes to bring five small dormitory-style units into a single home with modern amenities for their growing family.

Meghan and Harry moved into the Grade II-listed building just before the arrival of their baby son Archie in May.

Works including the removal of a chimney, re-finishing the roof, new staircases, fireplace installations and a new "floating" wooden floor, were detailed in planning application documents to the local council. British tabloid newspapers had speculated that the sprung flooring may be for a mother-and-baby yoga room, but Buckingham Palace has said those reports are false.

According to the palace, the only "floating" floor in the cottage was in the main kitchen area and was required by planners to temporarily protect the old flooring underneath during construction.

The Sovereign Grant, which pays for salaries of the Queen's staff, upkeep of palaces and official royal duties, including travel, footed the bill for the renovations.

The cost of all fittings, fixtures and furnishings were paid for privately by the Duke and Duchess.

Accounts for the Sovereign Grant, which were just released publicly , reveal that the monarchy cost the taxpayer £67 million (about $85.3 million) in 2018-19, up 41% from the previous financial year.

The anti-monarchy group Republic has called the rise in royal spending "outrageous," citing the Frogmore Cottage renovations and travel costs for Prince Charles, among other expenses.

"This year's increases are outrageous at a time of widespread spending cuts. But this is just one detail in a littany of scandal," Graham Smith, head of Republic, said in a statement.

"If even one school or hospital is facing cuts we cannot justify spending a penny on the royals. Yet with all public services under intense financial pressure we throw £2.4m at a new house for Harry. This is corruption being hidden in plain sight."

According to Buckingham Palace, a large part of the £20 million ($25.4 million) jump was due to "higher levels of spending on property." Much of that spend was put toward extensive renovations to Buckingham Palace itself -- part of a decade-long refurbishment project to "future proof the building's essential services."

"The ten year Reservicing programme presents a unique opportunity for innovation and investment in one of the world's most prestigious and iconic historic buildings, thereby preserving it for future generations," Buckingham Palace said in a statement.

"The work is sequenced so as to enable the Palace to remain occupied and fully operational and The Queen's programme to continue to be delivered without interruption."

In the last year, renovations to the palace have included building a compound for contractors, stripping out the main boiler room to prepare for a new energy center and the conversion of an upper floor area in the West Wing to a new open plan office space.

Members of the royal family, staff and over 3,000 artworks have also been moved out of the East Wing to prepare for electrical and mechanical works.