Dust in historic houses
Since 1999, we've been undertaking scientific research into how dust affects historic surfaces in houses.
Partly funded by the Leverhulme Trust, this research has been carried out by the University of East Anglia, in partnership with the National Trust, Historic Royal Palaces and English Heritage.
These three heritage organizations are responsible for looking after historic houses whose contents are vulnerable to dust because they are on open display, instead of being protected within display cases.
Our conservators therefore wish to find out how dust interacts with historic surfaces. This interaction affects the appearance of objects, how they are cleaned, and how we protect them from dust:
- Dust can damage historic objects by altering their appearance, making them difficult to see and hiding historic information
- Dust can interact with an object’s surface, causing physical damage and chemical alteration
- Attempts to remove dust can cause damage by rubbing surfaces too hard, or cleaning away original materials
- Where dust has been left in place a long time, it binds strongly to the surface of an object and requires more complex cleaning techniques
We now know that the dust most visible on surfaces comes mainly from human clothing and, of course, the majority of humans in historic houses are visitors.
However, it is not so clear why dust sticks strongly to some surfaces if left in place for a long time. If we understood this process, we could determine:
- How often surfaces should be cleaned
- When they should be cleaned and how
- How to reduce the amount of dust landing on an object
- The cost of cleaning and protection, compared to the income earned from visitors
How do we tackle dust?
To reduce the wear and abrasion on surfaces, loose surface dust is cleaned off only when it is really necessary.
Cleaning becomes necessary when dust spoils the presentation of a room, but this depends on the nature of the house.
Some houses such as Polesden Lacey are kept looking glittery and sparkling, to remind us of the glamorous parties once held there, and so any visible dust is removed.
Other houses look more worn and dusty to remind us of their age and condition when acquired by the Trust, such as Chastleton House and Calke Abbey where historic dust remains visible.
This is how we tackle dust:
- From April to October on days when houses are open to the public, and before visitors arrive, we remove dust daily from every floor on which visitors walk (the ‘visitor route’), using a vacuum cleaner.
- On open days, we also clean sturdy surfaces that show dust, such as dark shiny wooden tables near the visitor route. For these smooth flat surfaces, we use soft cotton dusters folded into a pad.
- Each week, on closed days, we dust more intricate and fragile surfaces that are further away from the visitor route, such as chair backs and table legs. We use a variety of special brushes, and collect the dust in a portable vacuum cleaner. We tackle two to three rooms each week in turn.
- From November to March, when houses are closed to visitors, we dust every room thoroughly from ceiling to floor, including its contents. In this way many surfaces are cleaned just once a year.
- Depending on how dusty they become, more fragile objects are dusted at even longer intervals: every three or five years for books in dusty locations, or ceramics in draughty cabinets; every five or 10 years for tapestries; every 25 years for paintings.
If we reduce the amount of dust that falls on objects, they don’t need to be cleaned so often. This reduces the risk of damaging objects that are handled or moved during cleaning, and allows staff more time to monitor and record their condition.
As the greatest source of visible dust is people, we try to protect fragile objects from dust by:
- Designing visitor routes so that visitors don’t stand too close to fragile objects that cannot be dusted very often, such as state beds. Ropes and stanchions keep visitors at a distance that is calculated to control dust levels.
- Keeping visitor routes as straightforward as possible; the more people twist and turn, the more dust they produce.
- Protecting dust-sensitive objects that are near the visitor route, for example using ‘case covers’ or closing cabinet doors. These objects may be uncovered or opened on special occasions for visitors to enjoy.
- Placing the most fragile objects in special display cases that also control light, temperature and humidity to safe levels, for example the Chinese Bed at Calke Abbey, and the King’s Room at Knole.
What do people think about dust?
We are also interested in how visitors and staff see dust, because this affects how staff present historic interiors and therefore how visitors respond to them. For example whether they view the house as a home or a place of work, and enjoy its nostalgic decay or aristocratic splendour.
Understanding how people perceive dust in our houses helps us to know whether we are cleaning too much or too little, and how to adjust the pattern of cleaning in each place.