Bacup: Lime Pointing Day

Bacup: Lime Pointing Day

Bacup THI Project Manager Megan Eastwood, arranged a Lime Pointing Day with the present owner of St Johns the Evangelist, a Grade 2 listed building.

This former church provided the ideal venue for highlighting the challenges faced by home owners and construction professionals.

Constructed in the early 1880s, the present building was a replacement for an earlier church that had been destroyed by fire. The building added to historical context of the day and importance of using compatible materials when carrying out renovation and repair work.

Programme:

  • The programme began with an introduction to the use of lime in the preservation of historic buildings.
  • Why the renewal of interest in using hot lime mortars in the context of heritage and historic properties?
  • The disadvantages of using modern materials such as (OPC) cements on heritage buildings, and resulting damage created.
  • How lime mortars allow vapour evaporation from a building and added flexibility in the structure.
  • How Lime pointing could be ‘sacrificial’ and thus avoid costly damage to the stone work.
  • Importance of sourcing local/vernacular materials.

Demonstration:

Mixing quicklime with sand and adding water, the resulting chemical reaction causes the lime to heat or ‘boil’ and steam is given off, this process is called ‘slaking’.

The lime expands during the slaking process which gives us a richer lime mortar making it more flexible.

After leaving it to cool for about 30 minutes we used the ‘hot’ lime mortar for our practical session. Many delegates’ commented on how easy it was to handle.

We reviewed the methods of removing the older pointing, especially if it was cement based. The challenge is to avoid or minimise damage to stonework, using hand tools and chisels.

After a demonstration of how pointing can be applied, the delegates had a go!

Because some of the joints were very deep, over 25mm, the instructor explained the need to move in stages. This was due the need for lime mortars to be exposed to the atmosphere, as the mix set’s by a chemical process that requires exposure to carbon dioxide. This process of ‘carbonisation’ is needed by air set limes i.e. Hot and putty limes.

The practical demonstrations and ‘hands on’ session.

All had a good time, many really got stuck in!

The white lime rich mortar stood out in stark contrast to the original stonework (see photographs).

What was the answer? The next part of the process is to use a churn brush, which is vital for 2 things; 1) consolidating the pointing 2) exposes the sand, and blends the colour. (See photo) Sand was sourced locally and was part of the specified materials being used for the restoration work in Bacup town centre.

We would like to express appreciation to Megan and Freddie for making it such a pleasurable day, even the weather was kind us.

All delegates received a certificate of attendance, on behalf of Sympathetic Works and Bacup THI.

Useful sources of information 

Buildings Lime Forum.  website.
Historic England publication: Repointing Brick and Stone Walls.

THI Lancaster and Morecambe

Kate Smith from Lancaster and Morecambe THI, organised a number of events to highlight the need for Specialist Heritage Skills.
Theses events are to aid local economy, increasing awareness for the use of traditional materials on historic buildings.

with the support of the Construction Department of the Local College, practical demonstrations and ‘hands on’ sessions were arranged.

The Events Covered:

  • Stone Relief Carving.
  • Decorative Plasterwork.
  • Stone Lettering.
  • Lime Plastering and Pointing.
  • Stone Carving.
  • Introduction to Stone masonry.

The sessions we provided were:

  • Decorative Plasterwork
  • Lime Plastering and Pointing
  • Introduction to Stone masonry.

You will find out below what each session entailed.

 

Decorative Plasterwork.

In the British isles a rich a rich history of decorative plasterwork is found, fine examples are seen in the Lancaster and Morecambe Area.To protect what exists and restore what has been damaged, can be challenging.

This session we explored the history and development of both traditional solid run and fibrous bench work. The students were able discuss the application in conservation and restoration projects.

Our student enjoyed a hands on session.

Student’s ran a mould on a bench using what is commonly referred to as ‘Plaster of Paris’, they reinforce this plaster work with hessian scrim. Using Silicone moulds cast the students where able to make a number of centre piece roses. The students came to understand some of the challenges when it comes to the repair and restoration of historic plasterwork.

Lime Pointing and Plastering.

The preservation of heritage properties often relies on their maintenance and repair.

In this session we outlined the challenges of using historic materials rather than modern materials.

Such as OPC (Ordinary Portland Cement) that are used in favour of traditional lime mortars that have a softer nature, flexible, self healing and are vapor permeable or able to ‘breath’.  Students were able to observe the boiling process that produces a ‘hot lime’ mortar, using slaking granulated quick lime, aggregate (sand) and water.

Once cooled this mortar was used in a hands on session in the afternoon.

We demonstrated the correct use of tools both in pointing and plastering. Including how to get the mortar off the hawk or hand board and onto the wall.

Introduction to Stone masonry.

Buildings with the Lancaster and Morecambe area show how local stone played a part in the construction of the many buildings.  Because of the proximity to the sea, beach cobbles have also been employed in the construction of some properties notably in Park Farm House (1685).

The day consisted of a presentation of the challenges of preserving stone work which has been degraded by use of harder cement based mortars. The advantages of softer, ‘sacrificial’ lime mortars and their ability to evaporate excess moisture without damage to stonework. We demonstrated mixing ‘hot lime’ under controlled conditions and again used material in practical hands on session..

Our ‘hands on session’ introduced students to how to cut and dress sandstone. Roll mortar of a spot board and from a bed for the stone and construct a random stone wall.

All who attended expressed appreciation for the session and all they had learned.

If you are interested in any of our courses please take a look at our Training Course page.

We express our appreciation to all involved, especially to John the Brickwork Technician who’s help was invaluable and the college staff.

Useful sources of information.
Buildings Lime Forum.
Historic England publication: Repointing Brick and Stone Walls.
www.lancaster.gov.uk/business/..

 

Repair of Historic Plasterwork

The focus of this taster day was the repair of historic plasterwork including lath and plaster, repairing and replacing decorative cornices.

This taster is used as an introduction to the unit on conservative repair, we provided this taster as part the Masters programme in building, restoration and adaptation for UCLan.

Invited by Chris O’Flaherty course leader, we provided a taster course focused on the repair and maintenance of historic plasterwork.

Plasterwork discussions

This included discussions with the students:

  • Water penetration,
  • Damp and wet rot,
  • Dry rot,
  • Insect infestation and the effect on lime plasters used in decorative plastering including plaster lath walls.

Exploring the options and methods available for repairing and stabilising sagging ceilings, and decorative plasterwork.

Demonstrated with the aid of a panel, correct lath fixing and spacing where shown.

Hair in plaster is applied correctly to the lath.

  1.  The first coat called ‘a pricking up coat’, Is scratched to form a diamond pattern and left to set.
  2.  A second coat called a ‘floating coat’ was applied, the plaster is ruled and ‘devil’ floated providing a key.

A ‘hands on’ session for the students focused on moulds, casting plaster and fittings.

Fixing a repair to decorative cornices and/or panels, use of a bench and box moulds in small sections are to achieve desired cast.

In addition a lively discussion about traditional setting out and fixings, resulted in the students reviewed the advantages and disadvantages of both running plaster in situ (on the wall) or casting on a bench.

Awareness of materials and methods that are employed show some challenges in reproducing ornate plasterwork.

Using Room Temperature Vulcanization (RTV) silicone mounds, the students produced centre piece roses.

We express our appreciation to all the staff and technicians who provided us with the workshops at the Harris Building.

THI Accrington Training days

Townscape Heritage Intuitive(THI) Accrington

Spring and summer 2016 was a very active time for Sympathetic Works, why is that?

The 2nd Wednesday of the month an evening course was arranged for six subjects starting from April till September an hour-long course was set up, alongside Hyndburn Borough Council’s very own THI program in Accrington Town centre.

The venue that was chosen for these courses was Accrington’s very own Town Hall formally known as the Peel Institute, which was built in 1897 as a tribute for Sir Robert Peel a founder of the metropolitan police.

Each week the participants explored the historic town centre, discovering the hidden history that many do not realise.

The subjects we explored:

  • Shops of the past
  • How well do you know your building?
  • Using the right conservation materials
  • Heritage & Signage
  • Repairing and maintaining historic buildings part 1 and 2

 

Discovering more.

The students were taken to Warner street to see the Georgian heritage shop fronts.
Warner street’s colourful past started in the early 1800’s originally workers of Mr Thomas Hargreaves resided here, this street was one of the towns earliest paved road ways it later became the best thoroughfare in the town.
The street was not named right after it was build and so it was informally known as “new street”. Warner street get its name after Lee Warner whose family owned the land. You can find more information about Warner street by going to the website.
Sympathetic works had the privilege of conducting a practical course – using the right conservation materials – on one of the days. This course included a demonstration of Quick Lime Mortar Mix and how to use lime mortar on heritage construction.

As the weeks progressed, deeper understanding of the history of construction in Accrington became more apparent to those attending the course, with this knowledge the proper care can now be given when handling these historic building.

Accrington’s historic buildings can become an icon for the area.

Our practical courses have always been a favorite of all our student, and if you would like to arrange for a taster day please don’t hesitate to ask.

Uclan – Lime Plaster and Pointing Day

Lime pointing and plastering with UClan Conservation Graduate Students

UCLan students, studying MSc Building, Conservation and Adaptation course, came for a day to have a practical study of lime plastering and pointing.

During the day, the students learnt to make lime mortar, the practical application of it.

Trying out plastering and pointing, they had also watched the process of making Hot-mix lime mortar.

 Lime

Lime has been used for thousands of years as a key building material. Today it is still used in repair and maintenance of historic buildings.

Before dry hydrate powdered lime, lime mortars were prepared using lime putty or quicklime mixes (also known as a ‘hot-mix’).

You can still use these traditional methods of preparing a lime mortar in building and repair work today.

 Hot-mixed Lime mortars.

Hot mixed lime mortars are prepared by adding specific measures of quicklime to aggregate and water, together to form a mortar.

The quicklime reacts with water this generates heat, this simultaneously binds together with the aggregate to produce a mortar. This mixture can then be used while still warm (for certain works) or stored(‘banked’) for late use.

This varies from other methods of preparing lime mortars.

Slaked lime (putty or a dry hydrate powder) can be added to aggregate to form a mortar.

Hot-mixed lime mortars have some different properties to mortars prepared from mature lime putty or bagged dry hydrate powdered lime. Because the effect of the heat of the reaction, and the high alkalinity of the lime.

Hot-mixed lime mortars are prepared by adding specific measures of quicklime to aggregate and water. You then mix together the ingredients to form a mortar.

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The UCLan students observed the process of quick lime when it reacts with water. The process creates the steam that can be seen rising from the galvanised metal bin.

 

Townscape Heritage Intuitive(THI) Bacup

The 10th June 2015 in bacup a full day course was arranged for a groups of interested business, and land owners. but why was this day significant.

It was the first off site training provided by sympathetic works, since the business launch late 2014.

Sympathetic works set up this taster day alongside Rossendale Borough Council‘s very own THI program in Bacup’s very own Stubbylee Park.

The venue that was chosen for these courses was Bacup’s very own Stubbylee stables and the connected grounds.

The land once belonged to the Holt family who built the hall in 1808. In 1911 the land was given to the towns people.

The taster day consisted of a brief discussion in the morning.

By late morning the participants where then taken on a tour of the surrounding grounds,.

  • the stable and court yard was first,
  • the vegetable garden,
  • the hall’s exterior and the hall’s service yard.

Discovering more.

The students after lunch were then involved in a practical lime pointing training.

The students where shown a demonstration of how to make Quick Lime Mortar Mix. Also how to use lime mortar correctly on any heritage construction.

After being shown how to use the right conservation materials, they were given the opportunity to try lime pointing.

As the day progressed, the students where given more of an understanding of the history of construction in Bacup.

This became more apparent in the comments of the attendees.

The knowledge they receive will help them properly care for any heritage building they have the privilege to oversee.

Bacup is proclaimed as the best preserved cotton town in England, by the English Heritage.

Its town centre is designated as a conservation area for its special architectural qualities.

Our practical courses have always been a favorite of all our student, and if you would like to arrange for a taster day please don’t hesitate to ask.