Waterford institute of technology

Workshop Portfolio

1st Semester, Autumn 2014

Marie Wilgaard Kelly, w20069429

1/12/2015

Lecturers: Michael White, Terry Prenderville, Robert Doyle. Wordcount 2088

Introduction

This workshop portfolio is presented as a part of the BSc in Applied Conservation Skills

workshop module. This portfolio represents the practical assignments carried out in semester

1 of the programme.

Also included is the practical experience from St. Mary’s Hall, Kilkenny.

This portfolio will be covering the following:

- Building a brick and stone wall with lime mortar incorporating a camber arch and a

herringbone panel:

- Mixing lime mortar

- Laying bricks with lime mortar

- Laying stone with lime mortar

- Cutting the bricks of the skew back and the camber arch

- Laying the bricks of the camber arch

- Setting up and laying the bricks of the herringbone panel

- Re-pointing with lime mortar

- Cutting and laying a herringbone brick panel

- Building a stone dry wall

- Weather struck and cut re-pointing

- St. Mary’s Church: Raking out an external random rubble wall

This portfolio will conclude with a brief summary, references and an appendix.

Please note that the photos are taken by the author unless otherwise stated.

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Contents

Mixing Lime Mortar Page 3

Laying Brick with Lime Mortar Page 4

Laying Stone with Lime Mortar Page 10

Building a Stone and Brick Wall with Lime Mortar Page 12

Building a Brick Camber Arch with Lime Mortar Page 14

Building a Brick Herringbone Panel with Lime Mortar Page 18

Building a Dry Stone Wall Page 21

Weather Struck and Cut Pointing Page 27

Practical Experience from St. Mary’s Church Page 28

Summary Page 32

References Page 33

Appendix Page 34

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Mixing Lime Mortar

The lime mortar is mixed in a cement mixer. First mix the dry ingredients 3 x sand and 1 x

hydrated Lime. Then carefully add water a little at a time. Let the mixer run for a while to

ensure the mortar is well mixed. Hydrated lime is a high calcium lime, made by slaking the

quicklime by adding a precise amount of water to the quicklime. Hydrated lime is a powder

(McAfee, P). See appendix for more information on lime.

The sand is very important for the look of the finished wall. See below an example of how

different two different sands look on the wall. The beige mortar is made with river sand and

the sand in the darker mortar makes a stark contrast.

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Laying Brick with Lime Mortar

- Use a softer wetter mortar mix, because the brick will absorb water. See photo below.

- knead and work the mix with the trowel till soft and flexible:

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- make a “sausage” with the trowel:

- scoop up the “ sausage” and place it on the wall

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- bed down the mortar with the trowel

- apply mortar to the header of the brick

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- lay the brick and tap into place with trowel following the guide line and level

- scrape of excess mortar – be tidy to minimise staining of the brick

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- re-point using trowel and re-pointing bar.

- smoothing out the joint with re-pointing bar.

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- brush and clean wall before mortar is fully dry. The brush will also expose the aggregate in the mortar.

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Laying Stone with Lime Mortar

- Use a drier mix of lime mortar to prevent runs and staining of the stone. See photo below.

- Lay out stones in a pleasing composition. This wall is random rubble, so the course must be broken every 2 – 3 stones. Then bed down the mortar and lay the stone.

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- Scrape out the joint to highlight and define the stone, while still keeping the joint quite flush.

- An old worn down trowel is particularly good for scraping out the joint. See photo below. Brush the wall after.

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Building a Brick and Stone Wall with Lime Mortar

- Lay down the first course, taking great care to getting the dimensions right and keeping it level.

- Lay brick up course 1 – 6 and then lay the stones in the middle.

- Then lay brick course 7 – 12, making space for the sill and then laying the stones in the middle.

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- Great care must be taken laying brick courses 13 – 20, because the skew back for the camber arch has be cut and laid, before the rest of the stones can be laid.

- lay the bricks and mark the angle of the skew back. Give each brick a number and cut the brick. Lay the bricks in the right order and check with the level, that they are straight.

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Building a Brick Camber Arch with Lime Mortar

- ensure the skew backs are straight

- place the wooden support for

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- construct the camber arch on a plywood board and cut out templates in cardboard.

- Choose the bricks. Draw the templates on to the bricks and give each brick a number corresponding to the number on the template.

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- Cut the bricks and lay them dry on wooden support to see if the 7 mm joint is straight

- Re-cut the bricks that need adjusting and lay the bricks from the sides in. Mark the upper joints of the template on a flat stick and use that as a guide. Have the wooden support marked in the same way.

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- Lay the rest of the bricks of the arch. Finish of brick course number 21. Remove support.

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Building a Brick Herringbone Panel.

- lay out the bricks on a flat surface. Mark the size of the panel and cut the bricks

- side view of cut bricks

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- place strings for guidance and start with the middle brick.

- check meassurements.

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- place a flat stick at the bottom of the panel to support the bricks and keep them straight. Use a square block to ensure that all the bricks are laid at the same angle; 90 degrees

- lay the rest of the bricks and complete the panel in the wall

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Building a Dry Stone Wall

- set out the wall using squares and lines. The lines will help keep the wall plane.

- starting with the end of the wall, built with every second stone a through stone for strength

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- the face stones are laid into the wall between 1/3 and 2/3 in

- place through stones every 3 to 4 feet (Post, B)

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- fitting in pinning stones to stop the face stone from rocking and to keep the face stone level. Pinning stones are only inserted from the back of the facing stones.

- hearting stones are laid flat in the cavity of the wall, quite tight and neat. Use the biggest fitting stones.

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- keeping the stones level or slightly tilted into the wall

- keep crossing the joints and keep the facing stones level and plane.

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- the end of the finished wall.

- the side view of the finished wall.

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- The cap on the finished wall. Stones are stacked very tightly together. The hammer is used to ensure the capping stones are as tightly stacked together as possible. No movement is allowed at all.

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Weather Struck and Cut Pointing

A small trowel is used to fill up the joints. The vertical joints are cut straight first. Then the angle is shaped with the trowel and then the cut is made with the small trowel. The cut protrudes approximately 1 – 2 mm out over the brick. This joint can be used in period houses, where the facade is painted, but with the pattern of brick underneath. The weather struck and cut joint creates a very well defined joint through paintwork. (The Brick Development Association)

(Drawing courtesy of The Brick Development Association)

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Practical Experience from St Mary’s Church

St. Mary’s Church in Kilkenny is located just between the High Street and Kieran Street in St. Marys Lane. It is a large re-construction and conservation project started by Kilkenny County Council and the contractor is due to start in January 2015 and the work is scheduled for 16 months. The Church is from the 13th century and was originally a much larger building. The building itself has undergone so many changes over the centuries, that today there is only a shell left of what once was. The floor plan of the church was changed; the side aisles removed, the length shortened, a bell tower built and demolished, a new bell tower added and finally the whole church was turned into a community hall in the 1960’s. Now the building has been re-designed into a museum. The floor plan will be enlarged into the old original floor plan and a room will be built especially to museum specifications, facing out towards the River Nore.

The practical experience from St. Mary’s Hall was to rake out and repoint an external wall, which was not included in the tender documents. It is a random rubble wall with ashlar stone around the door opening.

Kilkenny County Council erected a scaffolding to protect the wall from the elements.

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The wall was divided up in a grid of 8 rectangles. The wall was marked with chalk and an identical grid with measurements was marked on the floor inside St. Mary’s Church. This was to keep a record of the pinning stones. When raking out often a pinning stones would become dislodged. A photo was then taken of the pinning stone in situ and the stone was then removed and placed in the grid inside in St. Mary’s hall. The pinning stones are important, because they have the same weathering as the stones in the wall and will therefore be put back in their original place, when re-pointing the wall.

The raking out of the wall is almost finished and re-pointing will commence early in 2015 depending on the weather.

The joints around the large ashlar stones in the door opening were quite narrow, in some places in under a millimeter wide. A small chisel was used to remove the old and loose lime mortar without damaging or chipping the stone. See photo of chisel below. It was more difficult to remove the cement on the wall. On the photo above the cement joint is visible in the corner behind my elbow. It runs all the way up and down. Some of it was already loose and was easy to move. After consultation with Evelyn Graham, the Kilkenny County Council Conservation Officer, it was decided to try and remove it all, because the stone underneath the cement was wet and visibly damaged by being covered by cement. In a few places chips of stone came away with the cement, but it was always wet underneath the chip. So the chip must have happened before the cement was chipped away.

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The chisel on the photo below is very small, but of high quality tool grade steel.

Photo of Wall at St. Mary’s Church with hot lime re-pointing from hot lime workshop clearly seen as the light grey mortar underneath the scaffolding.

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Evelyn Graham organised several lectures for us as a part of our work on the wall. In order to inform us and give us the understanding of the building needed to work on a conservation project.

The lecturers were as follows:

- 15th of October : Peter Cox (Carrig Conservation) and Claire Walsh ( Head Archaeologist)

- 22nd of October: Neill McCullagh (Architect) and Cóilin Oʹ Drisceoil (Archaeologist)

- 12th of November: Hot Lime workshop by Pat McAfee and Lisa Edden

Please see the Appendix for a summary of the different lectures.

We also had an introductory talk from Evelyn Graham herself including a full tour of the church and cemetery. Nessa from the ministry for Arts, Heritage and the Gaeltacht also gave us a talk about funding opportunities regarding education in the disciplines regarding building conservation. Evelyn Graham also gave us a talk and a tour of Evan’s Home, Barrack Lane in Kilkenny City, which another big conservation project underway in Kilkenny.

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Summary

This portfolio has described the practical assignments and experiences achieved in Semester 1 of BSc in Applied Conservation Skills at Waterford Institute of Technology.

It has covered the following:

- mixing lime mortar

- laying bricks in lime mortar

- laying stone in lime mortar

- building a brick and stone wall with lime mortar, incorporating a camber arch and a herringbone panel

- building a dry stone wall

- weather-struck and cut pointing

- practical experience from St. Mary’s Church, Kilkenny

I have thoroughly enjoyed Semester 1 and look forward to Semester 2.

Yours,

Marie Wilgaard Kelly

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References

McAfee, P (2009). Lime Works. Dublin: The Building Limes Forum of Ireland. All.

Post, B. (2015). How To Build a Dry Stone Wall. Available: http://thestonetrust.org/resources/how-to. Last accessed 8th Jan 2015.

The Brick Development association. (None). Mortar Joint Profiles. Available: http://www.brick.org.uk/resources/brick-industry/mortar-joint-profiles/. Last accessed 8th Jan 2015.

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Appendix Contents:

Lime Page 35

Constructing a Camber Arch Page 37

Dry Stone Wall Terminology Page 39

Dry Stone Wall Basic Building Techniques Page 40

Building a New Dry Stone Wall Page 42

Understanding Stone Page 43

Finding Materials for a Dry Stone Wall Page 44

Dry Stone Wall Building Tools Page 45

Summary of Lecture by Peter Cox Page 47

Summary of Lecture by Claire Walsh Page 48

Summary of Lecture by Neill McCullagh Page 49

Summary of Lecture by Cólin Oʹ Drisceoil Page 50

Hot Lime Workshop Page 51

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Lime

Lime is produced by burning limestone in a kiln, turning the limestone into quicklime. The quicklime is then by slaking (adding precise amounts of water) turned into either lime putty, which has a soft cream cheese texture or hydrated lime, which is a powder.

Quick lime, sand and water make a hot lime mortar. For more information see summary on the hot lime workshop.

Lime putty or hydrated lime mixed with sand and water makes a lime mortar.

The watery substance left behind from the slaking, can be used as a lime wash.

Lime sets and hardens by being exposed to and absorbing CO2. The absorption of CO2 slowly turns the lime back into stone. See the Lime Cycle below (courtesy of McAfee, P).

Natural hydraulic lime, also called NHL is in theory not a lime product, because it can set in water and is not purely dependant on the chemical reaction with CO2. Natural hydrated lime is also made from burning limestone, but is a less pure product containing clay or silica (McAfee, P). Natural hydraulic lime is natural, because no pozzolans, cement or other setting

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agents have been added to it. Pozzolans are materials added to lime to speed up the setting of the lime mortar, examples can be brick dust, ashes or tile dust. Natural hydrated lime comes in different classifications based on their ability to set in water and strenght: NHL 2, NHL 3.5, NHL 5. NHL 2 is the feeblest one and NHL 5 is the strongest one. (McAfee, P)

One of the very interesting things about our lecture on hot lime with Pat Mcafee and Lisa Edden was the fact that they have started experimenting with a mortar that is a mix of quicklime, NHL, sand and water. This is to take advantage of the properties of each product: lime being flexible and NHL being very strong and quick to set.

The reason why lime is so important in conservation projects is because is was often originally used and should therefore be used for conservation and repairs. Mortar is sacrificial and must be weaker than the stone or brick. This is not the case with cement or concrete, which is stronger and can therefore damage the stone or brick. An example of this is St. Mary’s Church in Kilkenny, where the cement used for re-pointing is so strong is damages the stone, when being raked out.

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Constructing a Camber Arch.

- First draw out the skew backs based on the following formula: Add 25mm for every 300 mm of opening. Width of opening is 685mm making the top width of the Skew backs 56mm. See drawing below. (Drawing by Author)

- Based on the dimensions of the Skew back, the arch itself can then be constructed. Calculate the number of bricks that can fit into the arch. It has to be an un-even number always, leaving a key stone in the middle of the arch. In this case it is 11 bricks with 7.0mm joint. It will always look better to have the joints of the arch thinner than the wall itself. The bricks in this wall are 215mm x 100mm x 65mm.

- First mark the opening dimensions, then the skew back and lastly a centreline. Divide up upper line this way: 685 + 56 + 56 = 797 – (12 x 7.0) (joints) = 713 : 11 (bricks) = 65mm. Divide up the upper line in 12 joints (7.0mm) and 11 bricks (65mm). See drawing below. (Drawing by author)

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- the camber arch is straight at the bottom, but to make it look straight and not drooping, a slight upwards curve is needed. This is constructed using the following formula: 1mm up for every 100mm in width. In this case 685, means an upward curve of 6.85mm. Draw this in and construct the support wood with the same curve.

- Draw in the joint and brick lines as above in drawing. Draw in the horizontal lines the following way. Take the height of the arch 300mm – 2 joints 2 x 7.5mm = 285mm : 3 = 95mm. There will be no joint top and bottom, so mark out 95mm – 7.5mm – 95mm – 7.5mm – 95 mm. It should look like the drawing above.

- Cut out templates in cardboard to match the drawing on the plywood board. Only half is needed, because the arch is perfectly mirrored. The finished templates should look like the shapes on the drawing below. (Drawing by author)

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- Use the templates to mark the bricks and assign numbers to both templates and bricks, so they match up in pairs. Use the drawing on the plywood to mark the curve of the support wood for the arch and the joints. Also use the drawing to mark the joints on the straight wooden stick for the upper line of the arch.

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Dry Stone Wall Terminology

(Excerpt from Brian Post: How to Build a Dry Stone Wall, www. thestonetrust.org )

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Dry Stone Wall Basic Building Techniques

(Excerpt from Brian Post: How to Build a Dry Stone Wall, www. thestonetrust.org )

Dry stone walls can seem complex at first with all the different parts and terms. Fortunately the basic techniques needed to build a strong wall can be condensed down to just five rules. If you follow these rules, your wall will be strong and good looking.

1. Cross the Joints:

This means that each stone should be crossing a joint below so that it is setting on two stones below it. What should not be done is to stack stones so that there are vertical joints running from one course to the next. Such joints are called Running Joints or Stack Bonds. Walls with running joints are very weak and look poor. The image to the left is looking at the face of a wall. Correctly built is on the left, the right is built wrong.

2. Set the Length of the Stone into the Wall:

This means that the end of each stone is the part visible in the final wall. In other words the length of each stone is perpendicular to the direction of the wall. When stones are placed with the wall so that the sides are visible, it creates a much weaker wall and is called trace walling or face walling. Think of how firewood is stacked, with each piece perpendicular to the overall direction of the stack, so all you see are the ends of the pieces. A stone wall should be built the same way. Throughstones (long stones the ends of which show in both sides of the wall) are an extension of this rule, and should be placed ever 3 or 4 feet to tie the wall faces together. Trace walling is one of the most common errors made, and is one primary reasons walls fall down. The images to the left are shown looking down on a course in a wall. Correctly built is on the left, the right is built wrong.

3. Heart the Wall Tightly:

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The wall should be built as solid as possible. Gaps in the interior of the wall, between the face stones, should be tightly filled with small stones. The tighter the hearting, the stronger the wall. However fewer larger hearting stones are much stronger than many small little bits. Anything that can be easily shovelled is too small to use for hearting (and absolutely no concrete or soil!). Hearting stones are much better if they are flat or angular. Rounded stones can act like ball bearings. Hearting stones should be placed individually, not randomly thrown in. Hearting takes place as the wall is being built, make sure each course is completely hearted before beginning the next course. Not properly hearting a wall allows stones to move independently of one another, resulting in a structurally weak wall that will not last.

4. Build With the Plane of the Wall:

This means to align the stones so that there is an even plane to the faces of the wall. String lines are especially useful to keeping an even plane to the wall. The outer most ‘bump’ of each stone is what should be in-line. By doing this the wall will look smooth and even when you stand back. This applies both in cross section and in each course as the images below show.

5. Keep Stones Level:

Walls should be built so that the stones and courses are level. This is more apparent when using flat stones but applies to nearly all walls. Stones should be level both into the core of the wall and along the face. Stones that are not level will tend to slide causing internal stress in the wall and will eventually cause failure as the wall shifts over time. While there are a few local styles and techniques that don’t follow this rule (ex: herringbone wall), it should be followed when building typical walls, and especially when you are learning to build. This rule is especially important when building on sloping ground.

These are the basic rules of walling. If these rules are followed your walls should be strong and beautiful. There are also many more techniques that will make your wall even stronger, and features that can be incorporated for different purposes and situations.

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Building a New Dry Stone Wall

(Excerpt from Brian Post: How to Build a Dry Stone Wall, www. thestonetrust.org )

Building a new wall begins by preparing a foundation. When building a field wall, remove any topsoil, roots and organic matter from the where the wall will be built, and firmly compact the subsoil. Typically 4-6 inches below ground level is sufficient. Just like for rebuilding, clear space is needed along the wall. There should be sufficient access to have the stone delivered right next to where the wall will be built. If not, you will need to figure out a way to get it there. When stone is delivered in a dump truck it leaves a big pile, sizes are all mixed up, and hearting, if there is any, is at the bottom. It is worth every bit of your time to sort through the pile before you begin building. I find the most efficient method is start on one side of the pile and sort it into rows according to thickness, not overall size. As the pile gets sorted the rows get longer. I set this up so that the rows are parallel to the wall, with the thickest ones closest to the wall.

If you are working from palletized stone, it is still often worth opening all the pallets and sorting through the stone before beginning to build. Some palletized stone is already graded by size in which case sorting is not needed. However, these pallets are often intended for veneer, and lack the large stones you need for though stones and features. I try to avoid palletized stone whenever possible. It is more expensive, tends to have inadequate size variation, and dealing with the pallets and wire cages takes time. You also need a big piece of equipment to move pallets of stone, which often weigh over 2000 lbs.

Determining how much stone you need for a new wall is always a challenge. When buying stone by the ton, I find I get about 15 cubic feet of wall per ton of stone delivered. Note that is cubic feet, not square foot of wall face, so if your wall is an average of 2 feet thick and 3 feet, nine inches high, 1 ton of stone will give you 2 feet of length. This translates into about 1.8 tons per cubic yard of wall built. Of course, there is considerable variation due to the density of the stone, and how tightly the stone is stacked in the wall, so this is just a place to start.

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Understanding Stone

(Excerpt from Brian Post: How to Build a Dry Stone Wall, www. thestonetrust.org )

A basic understanding of stone is important to be able to wall efficiently. Some stone is easy to work with, and other stone can be very challenging.

Wall stone can be divided into two basic categories: level bedded and irregular. Level bedded stones have parallel top and bottom surfaces, and will often spilt into thinner stones. Slate and shale and sandstone are typically level bedded stones. Some limestone and schist are also level bedded. Some wallers will also refer to level bedded stone as regular stone.

Irregular stone accounts for all stone that is not level bedded. It can be angular or rounded. Irregular stone does not have flat parallel surfaces, and will not usually split so that it does. Granite and marble both break into irregular shapes. There is a continuous range from stone that is clearly level bedded, to stone that is clearly irregular. Most stone is somewhere in between. Irregular stone can also be cut, or spilt using feathers and wedges, to form regular shapes that it would not form naturally.

Walls built with level bedded stone often look neater. Irregular stone tends to look more rustic. However the skill of the waller and style being built affect this as much as the stone. Walls built with larger stone also tend to look more rustic. Smaller stones tend give a more tidy look. While you want to build the best wall possible, don’t try to force the stones into a character they are not.

Stones come in all different shapes the images below show some common shapes divided by how easy or difficult they are to build with. Some stones that difficult shapes can be trimmed (edges or points broken off) to improve there usability. Other difficult stones can be sporadically used throughout the wall, with better stones in between, without adversely affecting the look or structure of the wall. The very worst shaped stones often get smashed up into hearting. It is important to use all the stone in a consistent manner. There is a tendency to use all the nice flat stones right away, and then have a bunch of awkward shapes at the top of the wall. This looks poor and often weakens the wall.

Breaking stones is a skill in itself. Each type of stone works differently, some break easily and some don’t. Generally, breaking or shaping stones should be kept to a minimum, your objective is to build a wall and not to carve stones. It is always easier to break off the corners of a square stone than to make flat sides on a round stone.

How a stone is supported often effects how it breaks as does the direction it in which it was struck. I often find the speed with which the hammer strikes the stone is much more important than the apparent force or pressure exerted on the hammer when it strikes the stone.

The best way to learn how to break a stone in the way you want is to practice. Pay attention to how each stone breaks when you hit it. If it does what you want, then remember what you did. If not, adjust your technique for next time and try again.

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Finding Materials for a Dry Stone Wall

(Excerpt from Brian Post: How to Build a Dry Stone Wall, www. thestonetrust.org )

Finding stone to work with is one of the first tasks to undertake when working on a new wall or extending the height of an existing wall. Buying stone from a quarry or supplier is easiest, but is also expensive. Typical costs for quarried ledge stone or gathered fieldstone, delivered to your site, run between $125 to as much as $300 a ton. Generally most of this cost is due to the labor and equipment costs involved with quarrying, gathering, and shipping. Remember a ton of stone is not much when it comes to building a wall. If your wall is an average of 2 feet thick and 3 feet, 9 inches high, 1 ton of stone will give you 2 feet of length. Buying stone by the pallet is typically even more expensive unless you are dealing with a very small quantity. However, if you are looking for a very specific type of stone that is not available locally, buying palletized stone may be your best option.

On projects in rural areas stone can often be gathered from other places on the property. While taking down old walls as a source for material is generally not considered acceptable, and in some states is illegal, there are often stone piles in or near old agricultural fields. Often these were piled on bedrock outcroppings or near old trees. In some cases stone was also piled against a wall in order to remove it from the fields. All of these former agricultural dump spots can be good sources of stone. While there is a lot of labor involved to move the stone, the material is free.

Another good source for stone can be from local gravel and sand pits, which often screen out the rocks. While not all pit owners will allow you to pick rocks from there piles, some pits will sell the stones at a reasonable price. Some stone quarries and stone processing (shaping) facilities also have tailing or slag piles that can be picked through for a minimal fee or even free. Once again though, you typically have to supply that labor to go get the stone yourself. The main thing to remember though is to get stone as locally as possible.

I am often asked if a certain type or shape of stone is a good type of stone to work with. My usual answer is that all types and shapes of stone can be used to build a wall; the type and shape of stone just informs the style and look of the wall. Many people think of thin flat stone as being ‘good’ and round or irregular stone as being ‘bad’. In fact neither is true, they just lend themselves to different looks. Flat stones can be a pain to deal with because it takes so many to build a wall up to finished height. Large round stones may give a more irregular finish but can be much faster to build with. The one size of stone that can be difficult to work with are the fairly round baseball to softball size. While it is easy to build with some stones like this, it is very difficult to build a strong wall when a majority of the stones fit into that category.

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Dry Stone Wall Building Tools

(Excerpt from Brian Post: How to Build a Dry Stone Wall, www. thestonetrust.org )

The basic tools used in wall building have remained essentially unchanged for hundreds of years. For stripping out (taking apart an old wall), a shovel, pick axe, and pry-bar are the primary tools used. I also find a small garden claw or deep root puller is useful to clear dirt out from around large footing stones. It is also handy to have some type of clippers or shears to cut down weeds and saplings near the wall.

When actually building, the basic tools you need are a hand hammer or trimming hammer, a sledge hammer, and string lines and supports. The hand hammer or timming hammer (also often referred to as a waller’s hammer, walling hammer, or a stone hammer), is the most commonly used tool, I find a 2 to 3 pound weight is best, but some wallers prefer a 4 pound weight. If you are just starting out and on budget, brick hammer will work but it is too light too be efficient. Do not use carpentry hammers, as they may chip dangerously when hitting hard stones.

A long handled sledge hammer should weigh in 6-10 pound range. Most commonly available sledge hammers have a head that is essentially round. This works fine for smashing stones into hearting, but a large mash hammer or other similar hammer that has a boat shaped head, with a blade for splitting on one side of the head and a square face for trimming on the other is ideal for making controlled breaks. You have to be careful when buying hammers, as some are meant to be used to strike a stone while others are to be rested on the stone and then struck with another hammer. Improperly using a hammer can result in chips of steel breaking off the head of the hammer, and in the worst cases, flying into your leg.

Many professional wallers use a whole range of hammers ranging from 2 pounds to 16 or more. Generally the bigger the stone you are breaking, the heavier the hammer you should use. If you are just starting out, I would recommend a 3 pound and an 8 pound as a good place to start.

Many wallers also use chisels and points when more controlled shaping is needed. Chisels are great for splitting stones along there natural bedding (with the grain), and can be used for trimming and other breaking. However, while they give you more control, they take more time to use, so most skilled wallers only use them when precise control is needed. Points are like chisels that tapper in from all sides to leave a point that can be used for removing high spots.

Some hammers and chisels are available with carbide edges. This is very useful when working with hard stones like granite, which will quickly round over other hammers. However, these tools are quite expensive and require special grinding wheels to properly sharpen them, so they are only worth the investment if you are doing a lot of work with hard types of stone.

String lines are a lengthy subject that have their own section to cover them in detail. They are what they sound like, pieces of string that when tied taught, and properly used, provide a

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guide to build to. Masonry string is the preferred line to use. It is very tough, affordable, and is available from most hardware stores in a variety of bright colors, which help with make the lines stand out. Rebar stakes or wooden supports called batter frames are two of the most commonly used types of supports. Metal pins that can be inserted between stones in a wall that is being repaired are also common.

Other tools that are good to have when building include a tape measure and level, which are most useful when laying out a new wall. A wide range of pry bars, from 3 feet to 6 or more feet in length are particularly useful when dealing with stones that are too large to lift. In addition to the pry bars, having wooden blocks to use as fulcrums and temporary wedges can be very helpful.

Professional wallers may also use diamond saws and grinders to cut or shape stones that would be difficult to shape with a hammer or chisel. Professionals also use hammer drills to create holes for feathers and wedges, which are used to precisely split large stones.

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Summary of Lecture by Peter Cox

Peter Cox is the CEO of Carrig Conservation. Carrig Conservation is the Company appointed to survey, examine, test and give advice on the methods to be used in the conservation of St. Mary’s Church in Kilkenny. Peter Cox is a Chemical Engineer and Material Scientist.

Peter Cox spoke at length about the different tests of materials in St. Mary’ Church including mortar, paint and wood. This multitude of tests were all conducted in order to make a roadmap for the conservation of St. Mary’s Church, but also to find out more about St. Mary’s history. Unfortunately so many changes have happened to the building that very little could be learned from all the testing. So the most important test for the conservation process remains to be the mortar test and the result of the sand used originally. This makes it possible to re-create as similar as possible a lime mortar. The definition of this mortar can then be written into the tender documents. The result was a lime mortar with a ratio of 1:2 and the sand was sand from the River Nore.

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Summary of Lecture by Claire Walsh

Claire Walsh is the archaeologist appointed the head the excavations of St. Mary’s Church. The brief was to find the original footings of the church and the old bell tower. Claire also did excavations inside the church itself trying to find the original floor level. All this was necessary for the future design brief of the building itself.

Claire Walsh found and documented many tomb vaults with and without remains. She found the footings of the old bell tower and found that the building was very poorly built and that that was very likely to be the reason for the demolition of the old bell tower. Claire Walsh was unable to find the original medieval floor tiles, but she did locate the original floor level.

Claire Walsh found as Peter Cox had, that very little evidence of the buildings history remains in the structure and much is still a mystery. One of the things that puzzled her was why there was approximately 2 feet of loam covering the floor of the building. Another was where the original entrance was located.

Claire Walsh has since our lecture done further excavations inside the church to try and find the original floor. Based on my own observations looking at the bottom of the excavation in the transept, it looks like the aisle and floor was laid with bricks at one time. Further excavations are planned for the Monuments Room.

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Summary of Lecture by Neill McCullagh

Neill McCullagh is the appointed Architect for the re-construction and conservation of St. Mary’s Church. In his lecture he went through the methodology of re-designing St. Mary’s Church. Neill McCullaghs drawings and plan for St. Mary’s church are based on the historic context of the church, the city fabric context, the relationship to Kilkenny Castle and giving equal importance to all the changes in the fabric over the centuries. Because the church is of medieval origins, Neill McCullagh was analysing and making the drawings in a medieval state of mind, attempting to keep the design and interpretation in a medieval context.

Neill McCullagh’s aim is to reduce the risk to the building and that requires stripping back the building as much as possible in order to learn all there is about the building. It has taken 3 years to fully investigate the building.

Based on all the facts and research gathered, Neill McCullagh has drawn up the plans for the church using the original floor plan and floor level, which is approximately 800mm lower than the existing floor level. All the fabric of the structure has interesting facets and much of the repairs to the structure in the 1960’s will also be conserved on equal terms with the 17 th

century roof structure and the slate tiles on the roof.

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Summary of Lecture by Cólin Oʹ Drisceoil

Cólin Oʹ Drisceoil is the archaeologist appointed to conserve the area and the tombs that will be covered by the overhang of the new Kilkenny Room. Cólin Oʹ Drisceoil spoke of the medieval context of the church and the finds and conservation of the tombs.

Cólin Oʹ Drisceoil started his lecture speaking of the options for funding and how to make a conservation plan for the area in question. Then he put the church into a medieval context, trying to give a picture of what Kilkenny and St. Mary’s Church would have looked like and how the people of the day viewed the dead and the church. It was fascinating to hear him paint a picture of medieval Kilkenny. That French was the spoken language and Kilkenny was a busy hob of trade, so many languages could be heard spoken in the streets of Kilkenny and on the market place by the Tholsel.

William Marshall was a medieval knight, who built or was responsible for getting built much of Kilkenny, including the Castle, St. Mary’s Church and Canice’s Cathedral. William Marshall was a very prominent figure of his day and he lived in Kilkenny for approximately 7 years. St. Mary’s Church was the second largest parish church in medieval Ireland, so it was a very important building, because size was all important in medieval times.

After Cromwell’s attack in 1580 Kilkenny experienced a Golden Age and many of the tombs dates from this time. A church in medieval times was a house for the dead and the dead was an integral part of the livings daily life. The dead had to be cared for and this was done through the tombs, so the tombs themselves were very important. The living had to pray for the dead in order for the dead to gain access to heaven.

Cólin Oʹ Drisceoil also explained the national importance of the tombs of St. Mary’s church and their conservation.

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Hot Lime Workshop

Pat McAfee and Lisa Edden gave us a demonstration of hot lime mortar. Lisa Edden started by going through the health and safety precautions associated with working with lime: always wear protective gear: hi-vis, hard hat, steel capped boots, surgical gloves and protective googles. Lime is very alkalin and is caustic when wet. Lime can cause a severe chemical burn, when it gets into contact with the moisture on the skin or in the eye.

Next was the topic of sand and how important the use of the right sand is on the look and durability of the finished product. So-called bad sands are for instance building sand, because it is to rounded and fine. The sand has to be angled and have the right composition of grain sizes. Pat McAfee did a sieve test and explained the right composition. The sand has to have the bulk of the sand sizes in the middle and the level out in both the small and big sizes. The sizes are 5 mm, 2.36mm, 1.18mm, 600 micron, 300 micron, 150 micron and dust. See photo below of sieve test.

Another way of testing the sand is to pour sand into a glass jar with water and shake it very well and leave to settle in the different layers. The layers will show the composition of grain sizes. The test to see if sand has a high level of calcium is done by pouring mortar cleaner on the sand. The sand containing much calcium will bubble up. Calcium can make the mortar look dirty and it reacts strongly with the lime. Also run your fingers through the sand, if they come up dirty, it can cause shrinkage in the mortar, when setting. Sand will bulk up as much as 40%, so it is important to keep sand dry for correct measurements.

Lisa Edden also explained when to re-point and when to leave the mortar alone, meaning only re-point where and when it is necessary. If the joint is still flush, leave it be. If pinning

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stones are loose, re-point. If big stones have become loose, re-build the face of the wall. Do not remove bricks, because they are good for dating a wall. After re-pointing protect the wall with wet hessian in the summer and in the winter with hessian, plastic and frost blankets. If the wall gets too dry the mortar will crack, too wet and the mortar will wash out and frost will break up the wall.

Flora can be a threat to a wall, especially when Ivy and trees takes hold. Cut vegetation back as much as possible and spray wall and vegetation with biocide. The roots are treated by drilling and fitting in a pipe and filling the pipe with biocide. Do not pull out vegetation until dead, because it can bring down parts of the wall.

Pat McAfee ended the workshop by mixing Hot Lime and showing how to re-point with it. We all got a chance to try it. See photos below.

Mixing the hot lime mortar with showels and on a plywood board. It makes a very thick and soft mortar, that is lovely and smooth to use. The hot lime mortar sticks readily to both hawk and Frenchman. See photo below.

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Pat McAfee lastly showed us a hybrid mix, See photo of it below. The hybrid mix consists of 1 quicklime, 1 NHL 3.5 to 5 parts sand and one half part grit.

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