Monday, 9 March 2015

Is reversibility a valid conservation principle?

In February I made a post titled 'Minimum intervention: or the art of doing less'. The post sparked some interesting debate on the value of conservation principles. It was suggested there is a discord between the idea of being able to reverse modern interventions and the likelihood of those reversals ever being implemented. On one hand is the view that it is often unlikely that modern interventions will later be removed whilst on the other hand, reversibility is a fundamental conservation principle that seeks to protect heritage assets from permanent harm whilst recognising the necessity of change.

The best method for keeping historic buildings in a good state of repair is their continued usefulness and occupation. For this to occur it is necessary to continually maintain, alter, extend and modernise the building stock to bring older buildings towards modern performance standards and prevent redundancy.

"Reversible changes should be considered temporary. Non 
reversible change should only be used as a last resort and 
should not prevent future conservation action" - Burra Charter

Reversibility is the philosophy that an intervention can later be removed as if the intervention had never occurred, leaving no indelible harm to the asset. It must be appreciated that the works we carry out to buildings today, based on current demand, current trends and a current understanding of historical significance, is but a short period in the lifetime of a historic building. If we recognise that the changes we make today are only temporary then we should also recognise that those changes should avoid, where possible, any permanent harm to the historical significance of the building fabric or the use of the building.

Another theme here is the idea that we are only custodians of the historic buildings we inherit and it is our responsibility to maintain them, and often to develop them, for the enjoyment of future generations rather than only for our short-term needs or gains.

"The principle of reversibility should be used, for example, new insertions, 
such as sub-dividing walls, should be contoured around original features and 
mouldings so they can be removed in the future, leaving the original fabric intact" 
- BS 7913:2013 cl. 6.16

To re-state one of the valuable comments made on my previous post, principles are merely guidelines for those involved in the conservation of historic buildings. There can be no one-size-fits-all solution; every building and every project must be assessed on its individual merits. By the appointment of suitably qualified and experienced conservation professionals, familiar with the 'principles' of conservation, one can be more assured that the historical building stock is in safer hands than it might otherwise be. Reversibility is one of those principles and without it we would be opening up important historic building fabric to the possibility of permanent and damaging change that might be avoided by careful and conservation-minded management. 

Furthermore, reversibility permits modern interventions in historic buildings as part of carefully managed change, without this ideal historians might otherwise promote a philosophy of zero change in order to safeguard historic properties.

Wouldn't you agree that reversibility is undoubtedly a valid and important conservation principle, regardless of whether modern interventions are ever likely to be reversed or not? Let me know your thoughts.