Tackling pests, dust and damp: looking after our collections during winter closure

Though the House is closed to the public until 1 April 2022, there’s still plenty going on behind the scenes. Winter closure of historic sites provides an opportunity for English Heritage’s conservators to ensure that our interiors and collections are preserved for future generations. Collections Care Assistant Robin James tells us more.

The objects we have on display require constant and bespoke care and attention. However, there are common actions that preventive conservators can implement to preserve our cultural heritage. Preventive conservation fundamentally involves the arresting of natural deterioration to lengthen an object’s lifetime and preserve its display value. This involves controlling the environment, insect pests and implementing careful cleaning procedures.

Environmental control

This is one of the most effective methods of preserving historic objects. The air itself can be very harmful to cultural heritage if not maintained within certain limits of temperature and relative humidity. Organic objects, such as our beautiful furniture and gilt picture frames, take on or lose moisture to the environment according to ambient humidity. Moisture in the air causes changes in the object’s dimensions due to the volume taken up by water molecules. This kind of movement can cause cracking or flaking and so fluctuations in environmental conditions must be kept to a minimum.

In order to protect our sensitive collections, we use an environmental monitoring system which tracks fluctuations in temperature and relative humidity within the House. This provides English Heritage with data to inform what is needed to protect the objects we care for. Historic houses may also be equipped with humidifiers and dehumidifiers. Targeted heating can also act as an effective control measure. During winter, as temperatures fall considerably, indoor environmental conditions are monitored to ensure that cold and frost related damage does not occur.

Conservation cleaning

Winter closure also provides a valuable opportunity to carry out more thorough cleaning. Dust is a universal part of human life, and much of what settles on surfaces comes from our own bodies. Organic dust, such as skin and hair, can pose a risk to collections in the absence of a good housekeeping schedule, so it is important to make use of closed periods to deep clean our collections.

During winter, we use scaffold towers and other specialist equipment to clean more extensively and in harder-to-reach collection spaces. Organic dust absorbs moisture in the same fashion as the furniture and frames as mentioned above, and it causes it to become trapped against the surface of an object. Microclimates can cause discolouration and mould, so it is crucial that dust is not permitted to collect on the surface of historic objects. This is particularly important for metal items, which have a strong tendency to corrode when moisture levels are high. Cleaning must be carried out carefully, using soft brushes to lift dust from objects’ surfaces to avoid scratching.


Insect pests represent a risk to a variety of museum objects and can be very destructive in a short space of time if populations are not managed by conservators. Certain species, such as silverfish, develop in environments with high humidity and feed upon organic materials. Furniture beetles, more commonly referred to as woodworm, also enjoy very damp climates. In order to prevent these species from becoming established in a historic house or museum environment, it is essential that the microclimate is not neglected during closure. Pests often attempt to settle in gallery spaces without the presence of visitors to disturb them.

Although activities such as environmental control, conservation cleaning and pest management are year-round responsibilities of English Heritage’s conservation staff, during the winter months it is important to devote the additional time towards effective protection of the historic objects in our care. In the months when visitors are unable to visit, we are able to ensure that upon their return the collections that they know and love have been well cared for and preserved for many more years of enjoyment.