Roman Architecture

For my part of British Science Week, I was given the task of designing a display revolving around the topic of my choice, Architecture. Rather than focusing on arches specifically, I decided to broaden the information and open it up to many different aspects of architecture.  

As I am particularly interested in the topic, I learnt that focusing on the science side of architecture more difficult that I had first thought. I found that I had to first wrap my head around how the Romans actually managed to get their constructions to stand, and then concentrate on simplifying and limiting what I had gathered. The aqueducts were fascinating to research, as the Romans had a considerable grasp of how they worked and how to create the perfect speed of flow, ensuring even the smallest of towns received water! One of the most difficult things to grasp was the materials used by the Romans, as this was particularly scientific involving the Calcination of Lime creating Mortar, which was then used in essentially all of their constructions.

 

A Successful Architect

                                                            ]

                                                    

On the day, I had a number of visitors who were particularly interested in the materials used, and were fascinated by how light and porous some of the materials actually were (i.e. the Tufa block). As my table was located beside the Great Bath, I was able to point out where they could find these materials, which are hidden unless you’re looking for it!

The small collection of columns which showed the differences between the column orders was a particular interest to many, as the intricate details on the columns astounded many people. I was able to have a small piece of a column on display too, showing the details and thickness of the columns that were used by the Romans. It was especially impressive how much of the columns capital remained prominent, specifically for how heavy the item was and how damaged the bottom part of the piece actually is.

As it is not common practice to touch items on display, many people were hesitant to touch the materials I had out, and were even hesitant to touch the arch activity. After watching other visitors try, more people (not just children) began approaching the table and were particularly interested in trying their hand at being a mini architect!

Lucy Pidgeon, Bath Spa University 

The Roman Baths weren’t built in a day... so how did they do it?

Whilst preparing for National Science and Engineering Week at the Baths, we looked at how the Romans solved five building problems to achieve their bath-house.

The first problem was the marshy ground around the spring. This land was too soft to support the weight of a building. The solution was to pound many tall wooden logs, called ‘piles’, into the mud. These made a strong base for the massive bathstone walls which they used to form the reservoir around the spring.

The excavation of the Scared Spring in 1979.  The black spots are the tops of the Roman piles

The second problem was how to control the water which rose in the spring. The engineers wanted to use it in the Baths and then let it flow down the main drain. They built a low sluice gate in the wall of the reservoir. When the gate was pushed down, the water level would rise and flow down a box drain into the Great Bath. When the gate was lifted, the water rushed through the gap at the bottom straight into the main drain. The water level became too low to flow into the Great Bath, which could then be emptied and cleaned.

The third problem was how to lift the massive stone blocks used in the buildings. The Roman engineers chose to use a five-piece lewis-bolt. Three specially-shaped pieces of the bolt were inserted into a fan-shaped cavity in the stone, and they and a loop handle were held together by a pin. This handle allowed the stones to be lifted with a hook and pulley system.

The Lewis Bolt activity at the Roman Baths

The fourth problem came from the smoke from the hypocaust fires. The smoke would rise through any cracks in a stone floor and enter the warmed rooms above. The Roman solution was to mix and lay thick concrete floors on top of supporting pillars and tiles. The concrete solved the problem as it was both fireproof and made without cracks or joins.

The fifth problem came with the Roman’s liking for high, wide roofs and openings. These needed to be strong enough to support themselves and any wall built above them. The engineers used a semi-circular arch for these places as they knew that this shape spreads the weight sideways and downwards onto strong points on each side.

The Roman arch over the main drain in the Roman Baths

When you visit the Roman Baths you can see these solutions to their building problems. Keep an engineering eye out outside the Baths for these solutions which have been used in buildings and rivers since the Romans.

Nicola Pullan is a visiting researcher from the University of Sydney.

It's all about... Lime

This week is National Science and Engineering Week at the Roman Baths and I have been charged with donning my other hat and talking to you all about Lime (not the little green citrus fruit)…..

So what is Lime?
Lime is a general term given to a number of compounds containing Calcium. This blog will be focusing on Quicklime and Slaked Lime. Quicklime is a white caustic alkaline substance consisting of Calcium Oxide, which is obtained by heating Limestone (Calcium Carbonate). Slaked Lime is a white alkaline substance consisting of Calcium Hydroxide, made by adding water to Quicklime and it is this form that is predominantly used in traditional building methods to make plaster, mortar and limewash.

Calcium Oxide Molecule

The diagram below shows clearly how Limestone or Chalk - Calcium Carbonate - turns into Quicklime (Calcium Oxide) after burning or heating. If water is then added it turns into Hydrated Lime or Slaked Lime (Calcium Hydroxide). The cycle is complete when it reacts with Carbon Dioxide from the air around it, turning it back into Limestone. This process is known as the Lime Cycle.

The Lime Cycle

So why is Lime so important in historic conservation?
Buildings pre 1900 would not have been built with modern cement (with few exceptions in the late 19th century), but with a lime mortar. In order to conserve and repair these buildings, it is essential to use similar materials such as lime mortars, lime plasters and renders.

Does it have to be Lime?
Modern buildings generally rely on an outer layer to prevent moisture penetrating the walls, whereas buildings constructed before 1900 generally rely on allowing the moisture, which has been absorbed by the fabric, to evaporate from the surface. In essence, old buildings exposed to the elements are continually absorbing moisture, and the ability for the moisture to evaporate again is crucial to the welfare of the structure. Lime based building material is perfect for this two way exchange.

Using modern cement based mortars and plasters in traditional buildings risks locking-in the moisture, which could result in dampness internally and spalling of brick and block externally, as a result of freeze and thaw.

Pop along to the Roman Baths today, Wednesday 14th March 2012 between 4pm and 8pm and see me in action. I will be on hand to answer any of your lime based queries and demonstrating how we use lime based building material on-site.

For more specific information on applied lime based building material here at the Roman Baths, take a look at my previous blog – It’s all in the mix.

http://bathsbloggers.blogspot.com/2011/05/its-all-in-mix.html

Helen Harman - Collections Assistant

A Gorgon's Head?

Gorgon's Head?

I have puzzled over an alternative interpretation as to who/what the image in the centre of the Temple Pediment really is. I am sure that the character who dominates the centre is almost certainly not a Gorgon. For starters it’s a male; the only male Gorgon is Nanas (guardian of Zeus) who would have no relation to this site. Most importantly though, where are the snakes!? I see some thick wisps of beard but certainly no snakes. So who is this character?

The obvious choice for me is Neptune, not only does the aged bearded face resemble him but he is the God of water. The Romans had no natural explanation for hot springs such as those found at Bath, so to turn to a supernatural source for worship was not uncommon and here the deity of water makes perfect sense.

Artist illustration of Temple Pediment

If you look carefully you will see nestled in the corner of the pediment are Tritons; half men half fish creatures who were the servants of Neptune. If this image is not of Neptune then who is he? This mysterious figure could be any one of a number of water deities, perhaps the God Oceanus?

Mildenhall Silver Plate

Another theory is that in an effort to endear themselves to the native populous they governed, the Romans often amalgamated ‘their’ Gods with local ones (our very own Sulis Minerva is a great example of this.) Perhaps this is what happened here but current knowledge of local deities is very limited and offers no obvious links.

Next and perhaps most controversially it might be Mithras. This Eastern God was popular amongst the Romans at the time the Baths were active. Worship of Mithras was most popular among the military; soldiers of course built the Baths. The story of this God is also entwined with that of Sol (the Sun God).

As the Roman Baths website tells us the discovery of the Gorgons Head Temple Pediment “confirmed that the Roman site at Bath was unusual and attracted special interest to the site”.
Is it right to keep referring to this image as a Gorgon when it is clearly an interpretation that can be questioned? It’s hard to believe that once the head of Sulis Minerva was believed to be that of Apollo, What do you think?

Heath Meltdown

It’s All in the Mix

One of the best things about my role is that it is diverse and varied. I often come up against challenges and boy have I just met the newest!

One of the Roman Baths’ unique selling points is that the visitor has the ability to actually walk around and over the original Roman remains. Many people have commented on how this gives them a very personal interaction with the site and the people who used the baths many years ago. But it poses a very big question for the professional: how do we ensure public access is not detrimental to the remains of the Roman structure?

Recently reset piece of paving south east side of the Great Bath

We have a large amount of Roman secondary paving on site and, with general wear and tear, it is inevitable that pieces will become loose. When this happens, the pieces need to be reset – as quickly as possible - to ensure that the original position is not lost. This is not as simple as it seems - the technique of re-fixing the stones is an art.

Tools of the trade - pointing mix

The stones are fixed using a lime-based mortar mix, closely matched to the original Roman recipe in use on the site nearly 2,000 years ago. I have recently taken on the challenge of re-fixing the pieces (under expert supervision of course!). The mortar mix needs air to harden but also a damp environment to make sure this process doesn’t happen too quickly – a fine balancing act. It also needs to be protected for 2-3 weeks to ensure it has hardened both inside and out.

Colour matching the pointing to blend in with the surrounding stones

So if you see a piece of damp sack cloth covering any stone around the Roman Baths and a barrier protecting it, it will be because conservation is taking place- please be patient, we need to do it to ensure that you, the visitor, has the best experience.

If you would like to learn more about lime-based materials http://www.buildingconservation.com/  is a good place to start……

Helen Harman – Collections Assistant

A Wedding by the Water

This is the part of the day when I most enjoy my job as events manager. I am standing beside the Great Bath, in the early morning stillness, just prior to a civil ceremony. It is 8am and all I can hear is the hot water flowing from the Sacred Spring into the Great Bath and all I can see is the mystical mist rising from the water. In the 2000 year old remains of the Roman bath-house, the flickering torches and rising steam make this place one of the most atmospheric and romantic options for a wedding. In fact, if I were to marry again, I’m sure this would be the place for me!

Although the Great Bath is no longer covered by a roof, you need not worry about the weather as you’ll be under cover from the surrounding terrace above; and even when the rain falls on the naturally hot water, this only adds to the magical atmosphere.

Recently voted the UK’s ‘most seductive building’ in a poll by RIBA (Royal Institute of British Architects), the Roman Baths was also dubbed, ‘the place people would most like to take somebody on a date’.

The Great Bath

The registrars’ tables have been positioned beside the Bath, complete with floral decorations, and the first of the guests begin to arrive. The groom follows, along with a flustered looking photographer, anxious for the best shots in such an inspiring venue. At 8.25am, the bride arrives, escorted by three little bridesmaids, and the ceremony begins….

The Roman Baths has been licensed for civil ceremonies since May 2004. 8.30am is the only time that civil ceremonies can be performed (the Roman Baths is open to the public after this time), and is becoming increasingly popular. The Georgian Pump Room, up at ground level, is often used for morning wedding breakfasts and evening wedding receptions, along with the Terrace, overlooking the Great Bath.
For further information please go to www.bathvenues.co.uk Alternatively, if you would like to discuss your ideas or make an appointment to view the venues, please call 01225 477782 or e-mail bath_venues@bathnes.gov.uk . Click on the link for details of our wedding open day on 8th May.

http://www.bathvenues.co.uk

wedding open day link

Please note you will need to book a registrar from the Bath Register office to perform your wedding ceremony. They can be contacted on 01225 4777234 or e-mail

http://www.bathnes.gov.uk/communityandliving/marriages/Pages/default.aspx

A Monument in the Mist.

The number one question I get asked as I am walking around the site is, “what is the liquid you are spraying over the stones?”

Humidification system in action - Temple Precinct

Answer = The liquid is plain old tap water and it’s not being sprayed over the stones but into the atmosphere.

Next question = Why?

Answer = To prevent salt crystal growth which can cause stones to break where cracks exist and ceramic building material to breakdown.

Salt crystal growth - Temple Precinct

Next question = What is salt crystal growth?

Answer = Salts are contained within the stone and they expand as stone dries out, causing the weaker surrounding material to be pushed out. In a fluctuating environment the processes of dilution/absorption and concentration/expansion causes the stone to crack and clay to break down. Salt damage results largely from the growth of salt crystals within a porous structure. A broad variety of damage features—from granular disintegration to flaking and scaling. The water spray is keeping the environment stable i.e. constantly damp and aims to stop this process from happening.

Question = Why not just remove the salts?

Answer = Unfortunately due to the nature of the site, salts are constantly going to be present. The salts are present in the underlying soil fed by the natural spring water which is very rich in metals, salts and minerals and are drawn up by the stone and ceramic building material.

Pillars made from ceramic bricks - West Baths

Most people walk away very happy after this discussion= job done!

Can you think of any more monument conservation questions you might like to ask?

For a good place to start if you would like learn more about salt crystal growth follow the link below
http://www.getty.edu/conservation/science/salt/salt_publications.html

Helen Harman - Collection Assistant

A Token of Affection for Bath

Joanna and I (mostly Joanna) have been working on a display for down in the Pump Room’s Sun Lounge, which is now on display. The display features Georgian tokens that were minted in Bath and have images of local architecture.

Working on this project has really given me a greater appreciation for Bath and allowed me to explore the diverse nature of the local architecture which may, at times, seems so uniform and homogeneous. This project has exposed me to Bath’s more recent history and the affect it has had in building survival and use. Being from Canada it is quite shocking and intriguing to see images of local buildings that were hit during the Blitz, particularly ones that have since been restored.

Archive Photo of Bath

I’m hoping to get the chance to go and visit the buildings that appear on our tokens in person, or those that have survived anyways. I think it will be nice to take some pictures of them as they stand now, or perhaps what stands in their place.

As Joanna has already shown you some sneak peaks of the display I can't do that, but I can show you some interesting historic images of architecture in Bath that we ran across while searching the digital image archives for pictures for the display. I hope you enjoy.

Archive Photo of Historic View of Bath

Are there any particular buildings in Bath that you would be interested in seeing historic images of? Which buildings are your favourites?

 
Katrina Elizabeth