For many, purchasing a flat in an older building represents a chance to live somewhere with genuine architectural or historical interest. Many leaseholders prefer the general character and charm of living in, and around, older buildings; similarly, many building professionals prefer working with these buildings for the same reasons. Ornate detailing, historic sash windows and stucco renders are all, among many other features, cited as reasons people look to purchase older properties.
Historic buildings – and the flats within them – function in very different ways to modern blocks of flats. Modern apartment buildings typically function using dense, impermeable materials to act as an impenetrable barrier to the external elements, such as cement mortars and renders, plastic membranes and external cladding. Historic buildings, on the other hand, work by using materials – such as lime-based mortars and renders – which can absorb, hold and slowly release moisture over time.
Why does this matter? They way historic buildings are maintained has a critical role to play in ensuring their long-term durability and problems generally arise when modern technologies are applied instead of utilising the skills and knowledge from the past. For example, when cement-based materials or plastic membranes are used instead of traditional materials, this alters the way a building copes with moisture and, very often, is the cause of dampness related problems – as soon as a small opening appears in modern materials, water can enter a building and then find itself unable to escape; the dense, impermeable materials act in reverse of the building’s original ability to hold and redistribute moisture.
Staff at Historic England have expertly likened this to the use of a raincoat – we have probably all used a plastic, waterproof anorak that inevitably gets us wet when rain gets in through weak points at zips and hoods – much like cement renders and claddings can sometimes do. Conversely the use of a thick woollen coat can, almost counterintuitively, keep us dry by absorbing and then releasing moisture – as a lime render or historic brickwork does.
As a result, the careful use of materials in repair and refurbishment projects is absolutely key for those living in or managing historic blocks of flats.
Significance
For those living in, and working on, historic buildings, understanding conservation significance is key. Significance is, in very broad terms, understanding why a building is important both in terms of its physical appearance but also its historical context.
Understanding the importance of a traditional building usually starts with a Statement of Significance. This can be used for devising repair and refurbishment schemes but also for best practice around more routine maintenance and general preservation of our historic built environment.
When assessing significance, it is usual to consider the areas of aesthetic value (the way people see the building and derive enjoyment from it), communal value (the meaning of a place for different groups of people), evidential value (the evidence a building can yield part the past) and finally historical value (the way a building may have a link with a particular historically important person or event). By considering these areas holistically, we can understand why an building is important and how it should be conserved.
Major works
Like all buildings, historic structures will, inevitably, require major works projects. The nature of carrying out such projects on older buildings requires a greater level of attention to be paid to the project as a whole – cost, programme, scope and specification all come sharply into focus.
Any building project starts with the people involved in managing it. This can be individual leaseholders, property managers, building directors or anyone involved in maintenance planning. First and foremost, appointing competent professionals with experience in managing historic building projects and understanding their bespoke requirements is key. Building professionals in this field will start by assisting clients with defining significance, scope and the general overall approach. Secondly, the selection of the wider project team also needs consideration. There are many specialist areas within the field of building conservation – for example accredited conservators and historic render and paint specialists – who may need to be brought into the project team to provide specific advice. Similarly, in order to arrive at a sympathetic and technically correct specification, laboratory sampling of historic materials – such as mortars and stone – are often considered best practice.
For listed buildings and those within conservation areas, obtaining statutory consents must always be the earliest of considerations – prompt dialogue with the local conservation officer is always reccomended. In some cases, for listed buildings, a like-for-like repair schedule can be agreed that may not require Listed Building Consent; in other cases, a full application may be required. These matters should always be discussed with the Local Authority before proceeding.
When devising a scheme of works, the impact of the proposals, and means to mitigate any potential harm, must always be considered. A robust Statement of Significance will look at whether works actually need to take place, what impact they will have on the building in its wider context and propose ways to limit any harm causes. As a rule, the principle of ‘minimum intervention’ should be applied, although there can, in rare cases, be justification for intrusive or widespread works, subject to statutory approvals.
Retrofit
In this era of climate change understanding there is increasingly a focus on how historic buildings can be adapted to lower carbon emissions. This is, of course, a well-intentioned notion and, correctly executed, can have genuine benefits in terms of thermal comfort and reducing energy demand. Unfortunately, the more common outcome is a lack of correct design consideration by individuals who do not understand the different mechanisms for moisture management in historic buildings, leading to worse conditions than before retrofit works took place. Examples of this include the use of modern insulations, dense, impermeable floor and wall materials and a lack of attention to ventilation – usually resulting in mould and condensation problems and even hidden defects, such as outbreaks of rot. Bodies such as Historic England, Historic Environment Scotland and Cadw have released a range of excellent guidance documents for non-technical and conservation professionals alike, which should form the basis of any retrofit considerations.
Additionally, the introduction of low carbon heating and renewable energy sources presents unique challenges in older buildings. Solar panels and electric vehicle charging points require important decision making to reduce the risk of fires affecting historic buildings; the design, installation and operation of heat pumps requires expert advice.
As ever, appointing competent building professionals with experience and qualifications in retrofit of historic buildings is key. If you are considering a project on an older building or have any questions about this topic in general, then please do get in touch with us here at Earl Kendrick.
Further reading:
Why raincoat buildings are at more risk of rain damage | Journals | RICS
Assessing Significance | Historic England
Energy Efficiency and Retrofit in Historic Buildings | Historic EnglandEnergy Efficiency Measures for Older and Traditional Buildings | Cadw
