The twentieth century has not been kind to England's historic buildings*. Since the end of World War II, the unprecedented growth of our modern society has resulted in the loss of many significant historic buildings and their surrounding environments - essentially places and spaces that had survived relatively intact, in many cases, since the mediaeval period.
Fortunately, the large number of these buildings meant that many mediaeval and later buildings did survive but, critically, the knowledge and skills needed to correctly diagnose and execute repair and maintain these old buildings was all but lost. In the decades leading to the present, the widespread use of modern building materials and construction techniques, seen as a panacea to an old building's perceived shortcomings, have had disasterous results for stately homes and timber-frame houses alike.
In short, the introduction of modern building materials and construction techniques into historic buildings not only represents the loss of part of the historic building itself but, more often than not, actually goes on to cause much further damage by accelerating the decay of the building itself.
This is because old and modern buildings are made from two very different construction systems. Old buildings work on the principle of absorbing and releasing moisture to keep dry (the 'overcoat' analogy), while modern buildings work on the principle of excluding moisture by a system of 'barriers' to keep dry (the 'raincoat' analogy). Problems occur when these constructional systems are mixed (during maintenance, repair or alteration works). The effect is to trap moisture within the historic building, thus increasing dampness and causing the building to rot, often at an alarming rate.
This is because modern building materials are largely vapour impermeable, while traditional building materials are largely vapour permeable. This is the key concept to understand with historic buildings. Cement is the most damaging of all modern materials, whether applied as a render to a wall or a concete slab for a new floor, and should almost never be specified or installed.
One of the worst things that can be done to an old timber frame building is to apply cement render to the outside - unfortunately this practice still occurs today. The correct traditional material that should be used is lime, in all its various forms - this will create not only a healthier and drier building, but it looks better than cement as well!
Many building owners and builders simply do not understand this difference between the old and new and continue to apply modern materials in the mistaken belief they are doing the building some good. The truth is, this approach is fundamentally incorrect, hugely damaging to the building and ultimately a waste of time and money. For, at some time in the future, these works are likely to have to be corrected.
Damp & Historic Buildings
Damp is the most common issue with old buildings and certainly the most misunderstood and misdiagnosed. It is now accepted by informed building professionals that the introduction of modern damp proofing remedial systems (injected damp-proof courses, impervious plasters, etc) into old buildings is not usually the correct solution, does not work and, as highlighted earlier, goes on to cause further decay. Invariably, the cause or causes of damp are not correctly identified by those involved, meaning the applied solution only attempts to deal with the damp symptoms and not the actual causes. This is a fundamental flaw in the whole process. Unfortunately, this situation shows little sign of changing since building owners contact damp proofing contractors for advice (sometimes as requested by mortgage lenders when properties are sold). These companies are in business to sell particular products - not offer impartial expert advice as to the most appropriate solution for a particular building. Moreover, remedial works are often installed incorrectly by site operatives or cannot be satisfactorily installed in a particular situation.
If an old building has a damp issue it is usually because something has been done to the building (usually in recent times) that is incorrect or wrong for that particular building.
In our experience, historic buildings as 'low tech' structures are best treated with traditional 'low tech' solutions - not with expensive, incompatible 'high tech' modern methods.
Insulation & Historic Buildings
The current drive for ever more energy-efficient buildings is causing further problems for historic buildings. The simplistic application of modern insulation into roof spaces or onto wall surfaces can actually cause condensation within the building fabric again leading to premature decay. Many insulations commonly available are not suitable for use in old buildings despite what advertisers often claim. The application of insulation into old buildings is one of those things that should be carefully thought about in relation to established principles of building construction (warm roof, cold ventilated roof etc,) and should not be left to chance.
UPVC Windows & Historic Buildings
Another serious issue, and one that is not only damaging to old buildings but also to the wider appearance of towns and villages across the country, is the increasingly common practice of replacing original timber windows with modern UPVC counterparts. These windows not only look horrific in old buildings, but they are unsustainable and a false economy. There are various ways of making old windows more energy efficient - the fitting of 'slimline' double glazing for instance.
The appearance of Conservation Areas is being rapidly destroyed by the spread of these windows. Surprisingly, many Local Authorities seem unwilling to take any action - they could impose an Article 4 Directive. We believe a Conservation Area without any restriction on UPVC replacement windows is a nonsense.
'Listed' buildings have some level of protection against the kind of practices described here but those old buildings which are not listed have no such statutory protection and are particularly vulnerable, with many effectively ruined during so called 'restoration' or 'renovation'. A note of caution: although having passed Building Regulations (which apply only sparingly to much of this kind of work) these buildings are more than likely concealing costly problems which may only become apparent to owners several years down the line.
As most historic buildings have not escaped twentieth century intervention much of our work as architects is concerned with problem mitigation. This is often quite difficult as much modern work is not fully reversible and so bespoke construction details are often developed to address a particular set of circumstances.
However, despite all the above, we believe that with a little informed knowledge, an erudite design and skilful execution a historic building should provide a comfortable and rewarding experience and one that will attract a future premium.
*A 'historic' building could usefully be defined as that predating 1880 (the introduction of the damp-proof course), although the principles highlighted above could also apply to many buildings constructed up until as late as 1945.