Spotlight on: Physical Forces

Agent of Deterioration No. 3 – PHYSICAL FORCES

One of the most visual agents of deterioration is that of physical forces, and is perhaps the foremost agent which springs to mind when we are asked not to touch things in historic houses. Although we are trying to make our collections more accessible and engaging to visitors, hopefully this blog post will show you why sometimes it is in an object’s best interests to leave well alone if possible.

The main effects to objects are shock, vibration, abrasion and gravity. Often these effects are unintentionally inflicted upon objects.

For example, the photograph below shows a detail from the corner of one of the pier tables in the Top Hall. Look carefully at the arm and shoulder – it has recently been restored as the paintwork had been rubbed off, showing the different layers underneath.

Carefully restored paintwork on one of the tables in the Top Hall

The restoration makes it look as if the figure has always been in perfect condition. Yet this has not been the case…

Look at the picture below, which shows the damage that repeated rubbing had inflicted upon the carving and paintwork. This was caused by a number of factors, all human related. The positioning of the tables are such that when a wedding is held in the Top Hall, visitors come in and brush against the tables. In the past, visitors have also tried to use the figures as hooks to hang their handbags and coats on! After a few years, you can easily see the physical damage caused.

Damage caused by physical forces

Physical forces can be cumulative and occur over time (as seen above) or can be sudden and dramatic, such as dropping an item and breaking it, or larger disasters such as earthquakes.

Effects of physical forces include scratches, dents, holes, rips, tears, and breaking. Below are various photographs of objects at Nostell Priory which have suffered from physical forces. See if you can find a connecting factor between all of the images!

Scratches and a rip on the surface of the billiard table – too enthusiastic a player, perhaps?

Close up of the tear in the baize on the billiard table

Wear and tear at the top of the spine of books in the library. This is why you should be very careful when taking books from shelves!

Indentation in the Top Hall floor. It’s possible that this was caused by a high heeled shoe initially, and has increased over time.

Sofa in the State Bedroom. This was caused by a small child who started plucking stuffing from the arm before he could be stopped. We’ve placed a covering of netting over the corner to prevent idle hands continuing the damage!

Base of one of the lamps in the State Dining Room. Due to the natural low positioning of the base, it has gained lots of chips and scratches over the years. These have possibly come from shoes kicking against it, things being dropped on it, children playing near it, who knows?

Below is a photo of the servants’ stairs. In this instance, it demonstrates a case of physical damage that is not all doom and gloom! The repetitive movements of servants running up and down the stairs for many years has worn away the stonework, creating curved steps rather than flat ones. However, rather than being a case for restorers to repair any damage, the changed look of the stairs adds to the character and history of the house, and gives it charm.

Finishing on a happy note – not all physical forces are bad! The worn away stone steps bring the house alive and show the years of ‘upstairs downstairs’ that have taken place at Nostell.

Did you guess the connecting factor – that’s right, it’s us, humans!

It’s often noted that the worst threat to historic objects are humans, and this is probably true. However if we are careful how we treat them there is no reason why we can’t enjoy these collections for many years to come.

Ellie

Spotlight on: Water

Agent of Deterioration No. 2 – WATER

Everybody knows that lots of water and buildings do not mix very well, as seen in the recent floods in various parts of the country. Therefore to stay topical, I thought this week’s spotlight blog post would be about a second agent of deterioration – water.

We don’t want any water spillages onto carpets or furniture inside Nostell!

The damaging effects of water are numerous and varied. They include: efflorescence (more commonly known as the creation of ‘tide marks’) and staining, swelling of objects through intake of water, corroding of material such as metals, objects coming apart through the dissolving of glues, cockling and buckling, disintegration (for example when water comes into contact with paper), warping, shrinking, and the presence of water can also encourage the growth of mould.

This water mark was made after a flower vase stood on top of the table for a number of years. The amount of fading is from continual watering of the flowers and subsequent leaks/spillages.

Water can be divided into three main ‘types’. First there are the huge masses of water (which we really really don’t want) such as a flash flood, a river overflowing or a bursting water main. There are also maintenance issues that are concerned with water, such as a roof leak, a plumbing mishap, or general spillages during work activities. Finally, there are what you might call the ‘environmental’ aspects, such as those to do with condensation, rising damp, and changes in relative humidity (the latter is the amount of water in the air, which is closely related to temperature). Relative humidity will be covered in a future spotlight blog post. All of these would encourage the growth of mould and the influx of a variety of unwanted little beasties and pests.

On the ground floor we have real flowers as they really bring the house to life and there is less of a conservation worry for the floors. They are arranged in what is known as ‘oasis’, which is a floristry tool which absorbs water and reduces the need for watering, thus reducing the risk of further damage by watering. On the state floor, we use only artificial silk flowers as there is a greater risk of damage to objects in those rooms.

On the flowers we do put out, we regularly check for petals falling (like in the above photo) as they can attract pests. Lillies are a particular problem as Deathwatch Beetles like to mate in them. Pollen stems need to be cut off before they can be put on display.

A few weeks ago we had a torrential downpour of rain. This had an adverse affect on one of our internal downpipes which was already partially blocked. The damp spread rapidly to the outer walls (see the photo below) and a few days later water started leaking into the Breakfast Room, which is one of the state rooms. Fortunately it was noticed in time and the mirror could be taken off the wall, cabinets moved and paintings re-homed, but the wallpaper got rather damp. It was a busy morning! We’re still waiting for it to dry out before we can put things back in their place. Regular checks of the humidity levels are being taken to ensure that things are going back to normal and that the other items in the room are not affected by the change. We’ve taken some more detailed photos of the incident to share with you in a future blog post.

Damp on the outer wall of Nostell

Protective plastic sheets and paper towels to soak up the worst of the wetness. These were rolled back so that the public could still enter the room.

Damp inside the White Room. This is on our ‘to do’ list, as it will be a big task to sort out the damp problem in the room. One for professional conservators and restoration people!

We hope that this post gives you some idea of why liquids (in particular water) are not allowed inside National Trust properties, and the damage that can be done by this agent of deterioration. This is not to say don’t stop drinking it for refreshment – it is, after all, Adam’s ale!

Ellie

Spotlight on: Light

We in the conservation business are continually fighting on a daily basis with what is known as the Nine Agents of Deterioration. I thought it would be good to have a series of ‘Spotlight’ blog posts in the coming months to share what the nine agents are, their effects, and what we can do to prevent them taking their toll on Nostell Priory and its collections. You might be surprised to discover that most of the Nine Agents are what you also fight against when doing your own housekeeping!

Agent No. 1 – LIGHT

Light (or radiation) is one of the most obvious enemies of historical objects – everyone has seen things which have faded which were bright and colorful when first made but are now a shadow of their former self. The damaging effects of light come from both ultraviolet (UV) and visible light, and cause disintegration, fading, darkening, and yellowing of the outer layer of organic materials and some coloured inorganic materials. These are usually irreversible changes. We measure visible light in ‘lux levels’, and there are limits for what we consider the maximum level of light that should fall on an object. It is 50 lux for highly light sensitive materials (such as paper, watercolours, wallpaper, carpets), and 200 lux for moderately light sensitive materials (such as oil paintings and stone).

At Nostell there are a number of things that we do to reduce the effects of light attacking our property and the collection inside. Every window has a UV film on, which completely blocks out any harmful UV light coming into the rooms.

We measure the light levels in rooms on a yearly basis. On the two photographs below, there are little squares of card with blue patches – these are called ‘blue wool dosimeters’. They contain pieces of a special grade blue wool, and are left out for one year in places where we especially want to monitor light damage. When the blue wool fades, the amount of fading is measured with a spectrophotometer by a specialist conservator. If the wool is fading too fast, we know to move the object in question, or further reduce the amount of light coming into the room.

Blue wool dosimeter on the billiard table

Blue wool dosimeter on the dado rail below one of the tapestries

We place the dosimeters at varying points of distance from windows – the top photo’s dosimeter is fairly close to a window, and so we would expect some moderate fading. This blue wool directly above, however, is at the far at end of the room away from the windows, and so should hopefully show almost no fading at all over one year

Double blinds are also used to control the light levels. The dark green ones are the ‘blackout blinds’, and are lifted when the house is open to visitors. The pale cream ones are the sun blinds, and they are adjusted throughout the day to compensate for the movement of the sun. This prevents direct sunlight from hitting objects. Ideally, the double blinds should allow less than two per cent of the light falling on them to go into a room.

We’ve also recently taken delivery a conservation frame which focuses on UV light. Half of the frames has a UV-resistant coating, and one half doesn’t. When the beads are moved across the frame, they remain white when under the UV film, but turn pinky red when exposed to UV light in the section of the frame which has no UV coating – a kind of ‘sunburn’, you might say. The photo below shows the effect of UV light on the beads. It’s hoped that by looking at this frame, visitors will understand about our fight against light.

UV bead conservation frame

Ellie