Spot checks!

One of the most important things we do at Knole is keeping an eye on the environmental conditions in the Showrooms. We do this through a combination of ways. Our primary method is using individual monitoring sensors in each room that send a regular signal back to the office detailing the Relative Humidity (RH) and temperature in each space. By this method we can keep an up to the minute record of what’s going on.

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Our regular ‘Hanwell’ environmental monitors. This one is in a storage space and is showing an RH reading of 58%, right where we want it.

However, because of our current project and the work going on to improve the lighting, conservation heating and all sorts of other things it means that we don’t have proper radio monitors in some rooms right now.

 

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RH in some rooms sometimes reaches worryingly high levels. It’s essential to keep a good watch on what’s happening.

 

This means that our secondary method become more important and we have to do it more regularly. This method is using spot checks. Usually we go into each space in the showrooms and store rooms every two weeks to take temp, RH, lux and UV readings to make sure that our automatic monitoring is consistent with our handheld sensor.

While the sensors are gone in the second half of the house we send the intrepid Zena in with a hard hat and a monitor to take readings every week. This way we know what kind of conditions the historic showrooms are facing on a day to day basis in all weathers.

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Zena taking readings in the Ballroom

Oh the humidity!

One of the most important elements of conservation is making sure that our collection has the best possible environment to live in. In a house like Knole this is very difficult. It’s a large building with no heating or other environmental control. This means that the house can be at the mercy of the elements. Humidity and temperature rise and fall with the weather with no way for us to control it.

photoCondensation in the Second Painted Stair caused by high humidity (RH)

As part of the conservation project at Knole we will be having special conservation heating installed in the showrooms here. Sadly for our visitors and volunteers this does not necessarily mean that the house will be toasty and warm in winter! The heating will purely be there to control the RH (Relative Humidity) of the rooms. Relative humidity is one of the biggest problems we face here at Knole. When it is too high it causes condensation to build up on vulnerable surfaces, attracts dust and makes a perfect home for mould. It can also create perfect conditions for all sorts of pests such as woodworm and deathwatch beetle. When it is too low it can cause some materials to contract and crack, veneers to lift and glues to fail.

Because of the importance of RH and temperature we have to keep a very careful eye on conditions in the showrooms. If there are particular anomalies such as high RH where it is usually lower we can investigate what has happened. Perhaps there is a leak or a heater has failed. Although we don’t yet have control over the showroom temp/RH we have been able to have some control in some behind the scenes areas at Knole. We have special humidistats in special stores that will react to the Rh in a room and turn on heaters when necessary.

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 Humidistat in the storerooms.

The primary method we use to monitor RH is our Hanwell environmental monitoring system. If you visit Knole you may see the sensors dotted around the galleries.

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Here you can see the Painting Store monitor. It has an LCD display showing you the RH and temperature at the time.

 

Each room has a box and each box is equipped with a transmitter that relays the information it’s gathering to a computer in the office. This then plots a graph that allows us to see trends and patterns in individual spaces.

Within the National Trust we try to aim for an RH level of 40-60%. This represents the amount of water vapour present in air as a percentage of the amount needed for saturation at the same temperature. Because National Trust collections are often so varied and in historic settings there is no perfect RH that is ideal for all materials but this range gives us the best chance.

To make sure we have the most accurate readings possible we also take spot readings on a regular basis. This involves taking a handheld RH/temp monitor into each space and taking an extra reading. This is a good way to make sure we are obtaining accurate information. This is also our primary method of keeping an eye on RH/temp in the part of the house currently undergoing conservation work ready to be opened again next year.

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Here is Zena taking environmental readings in the Ballroom during the conservation work.

Knole suffers with frequent high RH which will be addressed when we have our new conservation heating. Until then we do what we can!

 

A Day in the Life of the Conservation Team

 

In a sense the title of this blog is a bit of a misnomer, because no two days at Knole are ever the same. Every day is different and it’s partly the variety that makes Knole such an exciting place to work. However, it’ll hopefully give you a flavour of what we get up to, day to day, in order to look after this magnificent house and its collection.

The work of the conservation team changes with the seasons. Over winter, when the house is closed, we are busy working in the show rooms, condition checking and deep cleaning the rooms and the all the objects in readiness for re-opening.

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Zena cleaning the textile of a chair during winter before carefully condition.

 

This winter has been a bit different because of the project. Although the first half of the house (from the Brown Gallery to the Leicester Gallery) had its normal winter clean, the second half of the house (from the Ballroom to the Cartoon Gallery) was emptied in preparation for the project work that will be going on in there this year. You can see some of the collection from the second half on display in our Great Store.

Now the house is open, our routine changes. In the morning, we spend the first few hours when the house is closed getting the show rooms ready to open. Every room is vacuumed to pick up anything left behind by our visitor’s footwear the day before. We also dust any flat surfaces in front of the rope barriers and check to make sure that no cobwebs have appeared overnight. Any glass is cleaned to get rid of dust or finger prints. The blinds are set, the curtains are opened and then we’re ready to welcome our visitors for the day.

 

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One of several long galleries at Knole that need careful attention every single day.

 

There are several reasons why we do this daily clean in the showrooms. Obviously we want the house looking its best, so people can fully appreciate the incredible collection that we have here. But it’s also a vital part of the preventative conservation work carried out by the conservation team. Monitoring the environment and general good housekeeping is the first step in combating the deterioration of our unique historic collection.

The afternoons at Knole vary hugely. Some days we are in the house working on various objects in front of our visitors. These conservation engagements can involve anything from textile cleaning to treating for woodworm and are a great way to show the public how we care for our collection at Knole. Other days we may be monitoring the environmental conditions in the show rooms or polishing door brass. But one thing’s for sure, no two days are ever the same!

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Injecting a pesticide to treat for woodworm. Something we do fairly frequently!

 

Thanks for reading!

 

Listening to the Furniture

At the beginning of March this year Knole was visited by Nigel Blades, the Preventive Conservation Advisor for the National Trust and a team of researchers from the Polish Academy of Sciences in Krakow. They were here to install some pioneering technology in the world of heritage sciences. With the help of furniture conservator John Hartley they have attached acoustic emission (AE) monitors to some of the most important objects in the house. The basic principal of these sensors is to listen for otherwise imperceptible noises emanating from objects as they react to the changing environment around them. 

Some of the sensors have been attached simply by wedging plastazote (an inert spongy material) into a convenient crevice, whereas others required gluing by a furniture conservator (although a hairdryer was needed to speed the drying process in the freezing temperatures at Knole!). Using a combination of gluing, wedging, and tying all of the monitors have been successfully attached.  

John Hartley preparing the sensor mount (left) and the finished sensor (right).

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Sensor wedged with plastazote into a convenient gap in the 17th century Gole table.

 

These monitors are designed to pick up the tiniest cracks and pops emitted by the furniture as it reacts to the environment around it. The relative humidity (RH) in the Showrooms of Knole can cause certain materials such as wood and metal to expand and contract as it fluctuates. It is impossible to tell how much the objects themselves are moving with the naked eye and so this AE method has been developed to help us better understand what seasonal variations in RH are doing to our collection. The sounds the equipment are monitoring for are so tiny they couldn’t hope to be heard without these specialist sensors. 

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The monitoring equipment in the Spangled  Bedroom

 

Sensors have been attached to 4 objects in the house; the Gole table and a torchere in the Great Store and the Jensen table and a torchere in the Spangled Bedroom. Selecting these objects allows the researchers to compare the effects on similar objects in varying conditions. The Spangled Bedroom currently has no environmental control at all. This means the the temperature and relative humidity change with the weather conditions outside with no human intervention. The Gole table in the Great Store however is subject to environmental control which keeps the relative humidity below 65% at all times. 

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The full setup on the Jensen torchere in the Spangled Bedroom.

 

The ideal conditions for a mixed material collection in the National Trust is between 40% and 65% although this is not always possible. Part of our long term conservation project at Knole is to try and install environmental control throughout the Showrooms so that the RH can be carefully controlled.  

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Every room has an environmental monitoring device like this. The Spangled Bedroom one has been placed behind the table and is recording temperature and RH every 15 minutes.

 

The AE project will run for a full year from now and it will allow us to understand and better manage the change from an uncontrolled to an RH-controlled collection. The sensors and laptops will be left in their current positions permanently and will be checked remotely from Poland once a week to make sure everything continues to function properly. 

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Furniture conservator John Hartley (left) and researcher Marcin Strojecki (right) discuss the placement of an AE monitor on the Gole torchere.

 

It was fascinating to see researchers and conservators of different disciplines come together at Knole to put this project together. Hopefully it will yield some interesting results!

 

Thanks go to Nigel Blades and everyone on the AE project team for providing the information and pictures in this weeks blog.

 

Monitoring the Great Stairs environment

The Great Jacobean Staircase at Knole, Sevenoaks, Kent

The Great Staircase was entirely remodeled by Thomas, 1st Earl of Dorset, between 1605 and 1608. It formed a key stage in the formal procession of the family and their guests from the Great Hall to the state rooms on the first floor.
The Great Staircase at Knole was remodelled by Thomas, 1st Earl of Dorset between 1605-1608 at Knole, Sevenoaks, Kent

The wall paintings decorating the main staircase at Knole are rare and very important survivals of Renaissance decoration. Dating from about 1603, they are one of only two complete schemes which survive from this period (the other is at Harrington Hall in Worcestershire) and presage the development of sumptuous painted staircase schemes in the late 17th or early eighteenth century, as seen in the King’s Apartment at Hampton Court Palace.
The Great Staircase from the landing at Knole, Sevenoaks, Kent

The paintings were executed in oil on plaster and have been unstable from an early period. Oil paint tends to lift and flake in the English climate, and their location also makes them particularly vulnerable to damage by touching. Flaking eventually leads to loss of the paint, seen in the white spots over the painted balustrade. The following images illustrate some of the damage and earlier remedial conservation repairs that have taken place over the years:

Areas of paint flaking revealing the plaster underneath

Areas of paint flaking revealing the plaster underneath

Cracking in the paint surface

Patches of previous repair, some of which are now failing and the paint is flaking off again

Patches of earlier repair, some of which are now failing and the paint is flaking off again.

As a part of our Inspired by Knole conservation project we are currently undertaking some extensive environmental monitoring of the staircase, internally and externally. We have placed temperature and relative humidity sensors on the external wall of the staircase and on the inside wall.

The external sensor, on the east facing wall

One of the internal sensors, on the north wall. The second is positioned on the east wall

One of the internal sensors, on the north wall. The second is positioned on the east wall

This will allow us to monitor what the temperature and relative humidity levels of the external wall surface and the internal wall paintings. Using time lapse photography we are also recording where direct sunlight falls on the external and internal walls.

The time lapse camera recording direct sunlight on the external wall of the Great Stairs.

The time lapse camera recording direct sunlight on the external wall of the Great Stairs.

 Our conservators who came to install the monitoring equipment also took some thermal images of the walls, another method to record the temperature of the wall surfaces.

Inside thermal imaging shot

Inside thermal imaging shot.

 

We are also monitoring another two wall surfaces to draw comparisons with the Great Stairs. The Spangled Bedroom, with new render and insulation; and the Brown Gallery which has relatively new render but no wall insulation. In these locations we have a temperature and relative humidity on the external surface and in-between the render and internal plaster. By monitoring the effects of new render and a wall with and without insulation, this will help us decide what the best method of protection will be for the Great Stairs wall paintings.

Alex, Emily, Lucy, Melinda, Sarah and Zena

A winter clean and other things

Wow – where did November and December go?  We’ve been so busy winter cleaning Christmas crept up on us.  The house has been a hive of activity.  We’ve worked our way through all the show rooms, condition assessing and cleaning all objects and furniture, which are now put to bed under their winter covers.

Lucy and Melinda cleaning one pair of torchere's from the Spangled Bedroom

Lucy and Melinda cleaning one pair of torchere’s from the Spangled Bedroom.

Winter cleaning in the Brown Gallery.

Winter cleaning in the Brown Gallery.

Newest member of the team, Alex, gets to grips with vacuum cleaning tassels!

Newest member of the team, Alex, gets to grips with vacuum cleaning tassels!

Zena vacuum cleans the textile of one of the Brown Gallery chairs.  Before beginning with the cleaning Zena condition checked the chair and updated the records on the laptop.

Zena vacuum cleans the textile of one of the Brown Gallery chairs. Before beginning with the cleaning Zena condition checked the chair and updated the records on the laptop.

The Cartoon Gallery 'put to bed'

The Cartoon Gallery ‘put to bed’

Hannah, one of our volunteers, removes dust from the silver urns in the King's Room.

Hannah, one of our volunteers, removes dust from the silver urns in the King’s Room.

Once the surface dust is removed, tarnish is then cleaned away using a Goddard's silver cloth.

Once the surface dust is removed, tarnish is then cleaned away using a Goddard’s silver cloth.

Working alongside us in the show rooms have been conservators, architects and archaeologists.  Sadly they weren’t helping us with the winter clean, but carrying out enabling works to help inform the interior conservation work due to start in 2016. Graham Marley, furniture / wood conservator, has been drafted in to lift our historic floorboards and wooden wall panelling. Some of the floorboards that were identified for lifting are those which have been lifted up in the past and so should have been easy to lift again.

Graham begins to remove some panelling in the Leicester Gallery.

Graham begins to remove some panelling in the Leicester Gallery.

Before enabling works began in any of the rooms, we had put them to bed first as a precaution in case a lot of dust was created in the process.  We had to move some paintings too before Graham could actually access the panelling.

This portrait is the largest painting we had to move.  It took 6 of us.

This portrait is the largest painting we had to move. It took 6 of us.

As well as a fair few cobwebs behind the painting, was also a patch work of panelling.

As well as a fair few cobwebs behind the painting, was also a patch work of panelling.

When we went through one of our secret passageways we discovered…

That the panelling in the gallery correlates with this now blocked up window.

…that the panelling in the gallery correlates with this now blocked up window.

With boards lifted and panelling down our architects have been able to investigate the unseen structure of the building to try and identify routes that cabling will take.  The show rooms will be re-wired during the work, which will allow us to upgrade our historic lighting and install various types of heating equipment.  By the end of the project the show rooms at Knole will have conservation heating for the first time in their history.

A section of panelling removed from the north wall of the Brown Gallery.

A section of panelling removed from the north wall of the Brown Gallery.

The enabling works also provides the opportunity to look how the sub-structure of the floors were constructed.  All of the work has been recorded by building archaeologists from Museum of London Archaeology (MOLA).  We’ve been hoping for some exciting finds under the floors and stashed away in the walls.  We haven’t found any human bones or lost documents, but plenty of other things that tell the story of how these rooms have been used over the centuries.

...and under the Leicester Gallery floor is part of a medieval wall, what remains of pre-Sackville Knole.

Under the Leicester Gallery floor is part of a medieval wall, what remains of pre-Sackville Knole.

Finds underneath the Brown Gallery floor.  That's where all our pencil's went!

Finds underneath the Brown Gallery floor. That’s where all our pencil’s went!

All the finds are recorded and processed by the MOLA archaeologists. Tassels and textile fibres have been found from the furniture too, even some cut human hair from under the Spangled Bedroom floor. Remnants of a 17th century hair cut...? Maybe.

All the finds are recorded and processed by the MOLA archaeologists. Tassels and textile fibres have been found from the furniture too, even some cut human hair from under the Spangled Bedroom floor. Remnants of a 17th century hair cut…? Maybe.

Archaeologists hard at work!  The hat was very necessary, Knole is far from warm this time of year.

Archaeologists hard at work! The hat was very necessary, Knole is far from warm this time of year.

In the New Year, we’ll be back to work off all the turkey and mince pies by cleaning all the show rooms from ceiling to floor. Scaffold at the ready!

Alex, Emily, Lucy, Melinda, Sarah & Zena

 

Protecting the Upper King’s Room

Old watering cans, empty picture frames, an old traveling case filled with empty shoeboxes, easels, mirrors, wall hangings, tables, ceramic bowls, an elaborate punched metal hanging lamp, a collapsible writing desk, a mattress, a tea chest,  stacks of prints in gilded frames, a whatchamacallit, and some thingamajigs. The Upper King’s room at Knole has it all, and all of it covered in layers of dust almost undisturbed for at the last 50 years.

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Situated above the sumptuous King’s Room on the south west side of the house overlooking the garden, the second floor space had fallen into disuse over a century ago and has been used by the Sackville-West family to store items no longer needed or not fit for purpose.

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The Upper King’s Room before being protected for external building work.

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Beginning in August, a team of conservation staff and volunteers began to go through the clutter, dusting off the cobwebs, carefully examining and recording the condition of each object. Tears, mould, dust, chipping gesso and gilding, insect holes, and general wear and tear were all recorded. Recording the condition of objects is an important part of the conservation process. It establishes a baseline for monitoring the object in the future, providing valuable data for the management of change in the collection.

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As the scaffolding for roof repairs went up around us, the Upper Kings’ Room remained pleasant through the Indian summer. It is a bright space, uncharacteristic compared to most of Knole’s stately dark paneled rooms. We slowly worked our way through the prints, newspapers, photographs, tables, chairs, and dishes, wrapping and packing them to keep the dust out when repairs to the roof begin.

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We saw objects that told stories,  that conjured up images of times gone by. My favorites were the many traveling cases that suggest the connection of the family to a wider world: a traveling case with portraits, that would likely be taken along when the family was spending a season away, and a case full of shoe boxes and perfumes, the remnants of a fashionable life. The objects in the Upper King’s room cannot begin to tell the whole story of Knole or the Sackvilles throughout the centuries but in the time I spent there, I began to get a feel for the hundreds of years of history told by the presence of these objects.

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The Upper King’s Room ‘put to bed’ to protect the contents fom external building work.

Leslie (conservation student internship)