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The vulnerabilities

How to make a flooded site safe In the event of a flood, the on-site damage and risk assessment should include consultation with the designated floodwater classification experts about the water supply – for example, is it clean (safe to drink), grey, or black? Where the water is classified as grey or black, the risk of biological contamination is high, as it may contain chemicals and/or sewage. In such cases, it is important to decontaminate the site in consultation with experts, and isolate contaminated historical materials by putting them in sealed containers or plastic bags. See references on page 162. 8 Ensure that wet structures and surfaces are thoroughly dried out. In the event that a building, structure or decorated surface incurs significant water damage, it is important to dry it out, in order to prevent: a. distortion and rotting of wooden elements; b. cracks in the plaster; c. mould growth; d. staining; e. salt migration. It is essential not to attempt to dry out old structures too quickly. Rapid changes in moisture levels may damage thin wooden elements, increase salt migration in walls and result in plaster cracks. In order to dry wet structures and surfaces: • Check and clear blockages from drains to expel water. On sloped surfaces, remove debris that may prevent water from draining. • Use buckets and pumps to remove trapped water. 76 First Aid to Cultural Heritage in Times of Crisis | 1. Handbook Critical damage is more likely in buildings where there has been fast-flowing water (for example, on hillsides or close to a breached dam), where the water level inside the building is (or was) more than 1m high, or if the load-bearing walls are made of raw earth. In this case, ask for the help of a structural engineer to assess the structural damage or the need for structural stabilisation actions before pumping out water.