During the second half of the twentieth century, the majestic monument Castle de Haar has been a child of concern. The castle began to show cracks as the foundation proved unstable.

Presumably several factors played a role in this. It may be that the medieval foundations were not after all able to cope with the enormous build-up of Cuypers' castle design. Another possible cause is the composition of the soil with clay and sand deposits. The development of nearby Leidsche Rijn and the construction and widening of the A2 freeway, with the accompanying digging of the very deep Haarrijnse Plas, will not have helped either.

In addition, at the time, funds were lacking for ordinary maintenance, such as painting the shutters, repairs to the slate roofs and maintenance of the park and collection.

In order to get and keep the castle, the other buildings, the park and the collection in good condition, a comprehensive restoration project started from the year 2001.

Restoration of castle and outbuildings (2001-2020)

Restoration of the chapel began in September 2001. From 2002 through 2004, the bridges, gates and quay walls, the garden ornaments and the stable complex at the Stable Square followed in several phases.

In 2006, work began on the first part of the castle itself, addressing the foundations of the leaning Knight's Tower. From 2006 through 2009, the outer shell of the castle was restored in phases.

Meanwhile, it turned out that not only the Knight's Tower needed a new foundation, but that the entire castle and part of the Châtelet did not escape this either. This was started in 2008; by the end of 2009, nearly 500 piles had been drilled, completing the foundation of the castle and Châtelet.

Restoration of the interior of the castle began in 2010, focusing on restoration in the basement and on the Beletage. The starting point for the restoration was to preserve as much as possible the current image of "the hundred-year-old lavish country house. After a pause of several years due to missing funds, the interior restoration of the castle was completed in 2020.

In 2013 and 2014, the Châtelet, the original guesthouse that now houses the offices and family apartment, was also completely restored.
Over the entire 20-year period, this brought all the buildings and installations back to excellent condition.

Park (2006- not yet completed)

A master plan was also made for the park and gardens of De Haar in 2002 with the goal of restoring everything to its former glory. In 2006, the paths in the park and the green part of the Stalplein were completely renovated. In addition, new signage was provided so that the beautiful spots deeper in the park can be easily found. In 2008, the Rose Garden and Box Garden were restored. Both gardens were restored as much as possible to the original design from 1896.

In 2009 the "Limburg" area was refurbished at the very back of the park, and in 2010 the entrance and the Deer Camp were redone. In early 2011, the Roman Garden was restored. In 2013, it was the Church Island's turn, followed by restoration of the Great Cour and the Chicken Garden in 2015. In 2016, the last style garden around the castle was recreated: the Small Cour. In 2020, the Grand Canal was fitted with new shoring. This does not yet complete the restoration of the park; in time it is planned to restore the remaining parts of the English landscape park as well.

Collection (2012 - not yet completed)

The collection of art objects, furniture, (wall) tapestries and utensils that make up the interior of the Castle is also the property of Stichting Kasteel de Haar. The collection consists of various furniture designed by Pierre Cuypers, silverware, tableware and a large number of art objects such as paintings, tapestries collections of glass and porcelain and antique utensils. It can rightly be called a Gesamtkunstwerk, because collection and castle belong together; they were largely designed or assembled by the same artist.

The collection is significant for the Netherlands in at least two respects, as there is no collection in the Netherlands that has been created in this way and managed and maintained as a unit for a century. The collection provides a penetrating and impressive picture of how the cosmopolitan European noble elite lived around the year 1900. In addition, parts of the collection, such as the family silver and other designs by Cuypers, 16th-century Flemish tapestries, objects from the court of the last Shogun, and furniture by international firms such as Maple & Co. and Maison Jansen are absolutely unique to the Netherlands.

Many objects in the collection are in urgent need of restoration. Unfortunately, no subsidies are available in the Netherlands for collections that are not government property. A priority list has been drawn up for the collection on De Haar, after which a restoration plan will be drawn up for each object with a cost estimate. On this basis, fundraising will then begin.

Obviously, the lead time for the restoration of the collection, which consists of more than 5,000 objects, is very long. Therefore, Stichting Kasteel de Haar is looking for structural funds to speed up the restoration of the collection.

Cost

The total restoration of the castle and its outbuildings has cost just under 40 million euros, 70% of which was paid for by government subsidies (State and Province) and 30% by own funds and some contributions from the Van Zuylen family and various private funds.

The park restoration has so far cost about 3 million euros. Because there is no national subsidy scheme for these restorations, the Foundation has sought other means. In particular, the VSB Fund has made a very large contribution. In addition, the SNS Reaalonds (now Fonds 21), the Province of Utrecht, the K.F. Heinfonds, the Municipality of Utrecht, Prins Bernhard Cultuurfonds, Dioraphte and Stichting Zabawas have supported these restorations.

Maintenance

In 2013, Kasteel de Haar Foundation was designated as a Professional Organization for Monument Preservation (POM) by the Minister of OC&W. Castle de Haar Foundation was among the first batch of seven organizations in the Netherlands to receive this designation.
By granting POM status, the State wants to reward organizations that manage Dutch monuments professionally and with quality, with confidence and with financial resources. This policy is part of the government's ongoing Modernization of Monument Care, which prioritizes professional handling of heritage.

POM status results in priority in the allocation of the maintenance subsidy from the Subsidy Scheme for the Preservation of Monuments (SIM). This subsidy amounts to 50-60% of the eligible maintenance costs. The remaining 40-50% is paid for by the Castle de Haar Foundation from the income from castle visits.