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Preserving heritage after floods

The challenge for heritage property owners after floods, fires or other disasters is in deciding on the method of restoring their building, whether it is made from granite, brick, cob, timber or wattle & daub. The complications arise from there being such a vast range of materials and construction methods. This means that there will always be unique problems associated with each building when affected by extreme conditions. For example; granite walls allow little moisture to permeate whereas cob and timber soaks up water in a flooding incident. Richfords Fire and Flood explain more

The challenges do not just apply to the external structure. A stone-built house may have a great deal of heritage oak panelling as a finish to internal walls. Water damage can cause timber to deform or split if restoration is not handled properly. There are health implications too as any moisture trapped in voids behind the panels can lead to rot, mould, fungal growth and even insect infestations.

It is important that anyone planning to restore a heritage building knows how far they can go without bringing in experts. For example, it is possible to strip away wall finishes in a modern house without too much problem. However, the same actions are not possible when dealing with a historic building with a listed status.

The aim of this article is to focus on a series of points covering issues to be aware of when a heritage structure suffers from damage and the actions that damage management professionals will carry out to return a heritage building to its former glory. It will also give you an understanding of how professional technical knowledge about drying and restoration techniques will help a property owner reduce the amount of an insurance claim and get their building, whether a home or a commercial premise, back into full operation faster.

In nearly every case, when floodwater enters a structure, it causes damage to some extent and will need attention. The amount of cleaning and repair usually depends on the severity of the causal event, the depth of water within the building and the length of time it has been soaking in for.

Shallow flooding on stone floors can usually be dealt with very easily but complications occur when the owner is not fully aware of what lies beneath it. In some cases, moisture can become trapped in small voids under or between the stones. In other situations, problems manifest themselves where there is a cellar or crypt below ground floor level. If the owner is unaware of the construction method and how it should be dealt with, it is always best to seek expert advice.

The problems really escalate if the water rises above the level of the floor and seeps into panelling and other wall-finishes. Moreover, the damage becomes worse the longer it takes to begin remedial drying. The cost implications can also be adversely affected if the wrong remedy is chosen for a structure and its materials. A key mistake in a heritage building would be to attempt to dry it out too fast – leading to warped, twisted and split timbers. Stone can also suffer from too much heat.

Restoring an historic building causes challenges, not only because of the structure, but also because of finishing materials and decorations. Plasterwork in many older properties is lime-based so it dries and hardens well after flooding. It can also aid in the drying operation because it allows the fabric beneath it to breathe. However, it may be a mistake to rip out plasterwork solely after carrying out a ‘knock test’ where the sound coming back indicates the wall is hollow. It may, in fact, be perfectly sound but is attached to timber battens. It may become unsafe though if moisture has affected the plaster dabs that hold a ceiling in place.

Historic buildings often contain fixings made from bronze, brass, copper, silver and gold. In most cases, these metals will not be damaged by one immersion so long as they are allowed to dry quickly. Problems can occur though if soaked timber is attached with nails or screws. These can start to rust if the surrounding woodwork is not dried out fully. If this happens, then there can be serious structural failure.

Thus, it is advisable to use expert technicians to dry out a building as they understand how much heat needs to be applied, at which part of a structure and for how long.

IMG_3562In general terms, it is advisable to dry as slowly as possible. A damage management organisation will also have the right expertise to know how to monitor the rate of drying. The danger is that wood panelling and other materials could become too dry. However, what is ‘too dry’? This is a measurement that changes for every building. Technicians will understand the structural science of a building and what that means for their restoration programme.

It is important for anyone carrying out work to find out if the building is listed and, if it is, what grade it has (1 or 2). If it is listed, then great care needs to be taken when removing anything. If a complicated piece of wall panelling needs to be removed, then this will need an expert eye making sure that listed-status rules are not contravened. Each piece of timber would need to be carefully dismantled, dried and then re-assembled in its original position. Also be aware that owners might not be fully conversant with what work can be legally carried out and will not have the power to allow you to undertake certain works anyway.

About Sarah OBeirne

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