Notes and Worksheets for Topic of Conservation & Restoration:

A building in need of repair

It is often the case heritage buildings require repair or maintenance. Heritage buildings require a different set of skills and knowledge compared to modern day construction. It is fundamental we appreciate such differences. The Heritage Council have outlined a number of conservation guidelines which must be followed when working on a heritage structure. The main conservation principles are: Retain the historical significance of the building. The aim should be to protect and reveal the buildings historical significance.

On researching the history of a heritage building it was revealed limestone was

used to build it. This type of evidence is critical prior to commencing work

on a heritage building.

Before work commences on the building ensure research is completed. The history

of the building will provide an indication of materials involved.

Conservation workers should ensure minimum physical intervention as possible.

Follow the key conservation principle of 'repair rather than replace'.

Traditional Sash Windows: The Problems!!!

Timber Decay:

Traditional windows are made of superior timber which is

justified by their longevity.

Some windows have lasted for over one hundred years and still

survive. If decay is found, always investigate the root of the

problem. For example if a window is leaking the leak must be

dealt with appropriately.

Wet rot:

This is visible when the paint begins to ripple and timber goes

soft. Over time the wood will lose its strength.

Wet rot occurs mainly on Horizontal members as this is where

water lodges and is allowed to soak. The moisture might soak

into the timber due to a lack of paint or break.

Infected sections of the window should be repaired or replaced

with exact replicas.

Key points when dealing with wet rot

All infected wood removed and 500mm beyond

All wood to be treated with fungicide

The cause of infection must be found

and fixed

All new timber must be treated with

preservative

Sash Cords and pulleys (right):

Over the years the build-up of paint causes sashes and pulley to become

immovable. When paint is applied over the sash cord it reduces its strength

and will eventually cause the cord to break.

Firstly remove paint which will allow the sashes to move.

Replacing the broken sash cord can be completed by someone familiar with

such work. The weights will have to be accessed via the side pockets in the

window frame.

The Repair or Replace method:

Check for any problems such as broken sash cords, putty breaks and

repair accordingly.

Repair rather than replace’

If windows are beyond repair, replace with new sash windows identical

to the original. This can be achieved by asking the local joinery shops

which specialise in the area.

After a new window is installed prime, under coat and gloss the window

as original one was. This will help maintain the visual setting of the

home.

In order to encourage the reuse of materials the guide ‘repair

rather than replace’ must be adopted.

This involves retaining as much of the original window as possible

timber, glass, weights. (sash cords will more than likely have to be

replaced)

Horizontal members are likely to suffer from wet rot as moisture is

allowed to lodge in this area. Inspect such members.

Cut away any infected sections of the timber and replace with identical

pieces. Ensure the character of the window is maintained. Ensure exact

details are provided to the craftsman completing the replacement.

When removing infected sections care must be taken to avoid breaking

the glass. This will particularly apply when removing the original putty

Original glass will be reused.

Conservation Worksheet

In order to avoid historical damage what key conservation principle must be followed?

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Evaluate the importance of this principle in order to maintain the integrity and historical

value of the building

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Explain how the maintenance of the traditional sash window is vital to the character of a

building:

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Name and explain one common problem associated with traditional sash windows:

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Explain how the outlined problem can be solved ___________________________________________________________________________

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Complete a well-proportioned labelled sketch of a sash window indicating

clearly areas where problems can occur:

A thatched cottage (right) is under conservation. Describe the

correct procedure required to restore the sash windows. Use

notes and sketches:

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Key Terms in Conservation

Restoration: Restoring the building to its original state using original materials and building

techniques. It is important that this type of work is carried out by specialists, who have

experience of working with old buildings.

Reconstruction: The alternative to restoration is to use new materials and techniques to add

to the building in its present state. When this is done the damaged parts of the building are

repaired and replaced using modern techniques and modern materials. An example is an

unused building is converted into apartments or offices

Care of the Built Heritage: The Department of Environment, Heritage and Local Government

is responsible for the conservation of both the natural and built environment.

Modern wall v traditional walls:

Veritical section.

Note cavity

Modern Walls: Modern walls are designed with a cavity which prevents moisture reaching the inner surfaces of the building. When moisture penetrates the external leaf it falls down the cavity and will not enter the inner surface of the wall.

Traditional walls:

Water penetrates the exterior surface

Traditional walls are thick as this is their means of preventing moisture from entering the inner surface. The wall functions by evaporation. When water penetrates the external surfaces it will dry out before reaching the inner surface due to the width of the wall.

Cottage with lime plaster

The moisture will remain in the wall long enough for the sun to shine and dry it out. The essential message here is that traditional walls require the use of lime when working when carrying out repairs and conservation.

Traditional walls require flexibility to allow for the independent movement of its parts.

The two key points are: Walls must be pliable and porous. In other words be flexible and be able to breathe. Secondly the material with the characteristic to achieve this is lime. What happens if lime is not used?

An example of where cement mortar was applied to the wall due to poor knowledge. This had to be removed.

Modern building materials such as cement will cause both visual a technical damage to the building. Cement stands out when applied, lime is more subtle. It is the technical damage caused by the application of lime that has more potential to harm the building. Traditional walls must be flexible to cater for the changing weather conditions. Cement for example does not allow for this.

decayed mortar joints

Common problem:

One main problem that occurs with traditional stone/brick walls is decayed and loose mortar joint. Such a problem needs to be fixed in order to prevent further damage to the building.

Solution - Repointing:

Sketching Skills 1:

Sketch the

representation of

a vernacular wall

and sash window

that has been

updated to

ensure less heat

loss

Sketching Skills 2: Sketch the representation of a

vernacular wall that shows that the wall is

breathable