A Basic Guide to Restoring Old Houses that are 50 or More Years Old
Like human beings, buildings will decay with age and their life can only be extended with proper treatment, care and maintenance.
Medical doctors will examine and treat the sick just like conservationists will examine old buildings – research the patient (or building’s) history, check for symptoms to assist in identifying the cause of the problem and then, recommend appropriate treatment. The wrong diagnosis and treatment will most likely result in rapid deterioration or death.
Research the History of the House
Gather information on the house – its history, age, original occupants, construction method. To find information on an old building, check the town library, historical society, museum, local/national archives or local building authorities.
Finding information from historical records can often be difficult, especially when building records are non-existent. Other sources of information are:
- records of old houses in the locality which may have been built around the same time;
- some old people who lived and are still living in the area; and,
- historians, archaeologists or restoration architects who have done some work in the area.
It is important to gather information on the history, building materials used, construction method, the original occupants and the age of the house.
Decide on the Objective of the Restoration
Restoring the house to its original state/use is ideal if the house has a historical, architectural or cultural significance i.e. it symbolises an important period, event or commemorates the life of an important person in history or it symbolises the culture and lifestyle of a people at a particular period in history.
Often houses or buildings that are over 50 years old that have historical, architectural or cultural significance may have already been identified and officially listed in a local registry of historical objects. If this is the case, one should check the local building authority for legislative requirements on restoring heritage listed buildings.
Partial restoration is ideal if the building is of value to the owner i.e. it may serve as a reminder to the owner’s family of their ancestors. In a partial restoration, the original external structure/form is restored and interior spaces may be modified to suit contemporary needs.
Assess the Building Condition
Advice on the structural stability of the house should be sought from a structural engineer.
It is important to ensure that the building’s substructure (foundation) is structurally stable and able to support the superstructure (roofs, wall, post and beams) before any restoration plans or drawings can be prepared or work implemented.
If the substructure is beyond repair, the structure should be demolished and a replica of the old structure built or reconstructed by re-assembling using the salvaged parts of the old structure or similar structure built about the same period.
Choose the Preservation Treatment
One important rule to remember in restoring old buildings – do not apply the same repair technique or treatment on a relatively new building to an old building (50 or more years old). New paint applied on a 50 year old wall may accelerate decay rather than halt it.
There are three restoration techniques:
- A dynamic restoration uses the techniques of reconstruction, re-assembling and refurbishing. Reconstruction is done by re-uniting some of the fallen fragments with the remaining portions still in their original places;
- A static restoration involves direct intervention (preservation treatment) of the materials. Some static methods are mechanical cleaning with steel brushes, repair or re-structuring and preservation actions such as waterproofing, damproofing moss repellant and other chemical treatments; and
- A combination of dynamic and static restoration.
In a static restoration, before treatment can be applied to the material – firstly, determine the nature of the building material; and, secondly, determine the cause and extent of deterioration.
To be able to recommend the appropriate treatment for the material, it is important to determine the factors causing deterioration. The extent of deterioration depends on the degree of exposure to the factors of deterioration i.e an exposed structure has a greater risk of deteriorating quickly than a sheltered one.
Deterioration may be caused by intrinsic i.e physical defects or extrinsic i.e. water, climatic conditions, atmospheric pollution. If deterioration is caused by intrinsic factors, replacement or reconstruction would be the most likely treatment.
Preservation treatment depends on the nature and classification of the material, whether it is organic e.g. soft and hard timber varieties or in-organic e.g. siliceous stone or brick.
Organic materials such as wood, are highly susceptible to deterioration agents. The treatment for wood is usually replacement. The recommended treatment for stone depends on the classification of the stone i.e. if it is siliceous or carbonaceous. Stone classification can be identified form visual examination, physical tests, chemical analysis or microscopic analysis.
In-organic materials are relatively stable and normally do not need much protection as objects which are organic in nature. In general, however, all materials are affected by adverse conditions and some objects which are in-organic can deteriorate very rapidly without proper care.
To ensure that the chemicals used for treatment are appropriate, the chemical should be tested on a small piece of the material before it is applied to the entire structure. It may be helpful to seek the assistance or advice from a geologist (or petrographer), timber technologist or chemist