C O N T E X T 9 5 : J U LY 2 0 0 6 23 solutions would require listed building consent. In such cases an assessment by an independent consultant can be stipulated. Such an assessment would ideally involve tests using BRE Digest 245. However, sourcing an independent assessment may not be straightforward. The cost of an assessment by an independent damp consultant is often prohibitive for average-sized domestic properties due to travel and laboratory expenses. The choice of independent consultants offering specialist damp analysis for historic buildings is also extremely limited and the quality of service can be variable. If you feel confident enough, it may be worth attempting a visual assessment of the situation yourself in the hope that there may be clear evidence of later interventions relating to areas of damp damage internally. Clearly, you may not be in a position where your professional indemnity enables you to dispute the judgement of another professional. Nevertheless, you may be able to persuade the client or building owner that it may be prudent to address the more obvious causes of moisture ingress before embarking on more damaging, and potentially more costly, procedures. It is more than likely that the source of moisture affecting the base of the walls will be due to later interventions. Even if this is not the case and the presence of rising damp is proven, the use of a French drain represents a possible alternative solution. Julian Bagg was an associate of independent damp consultants Ridout Associates before working as a conservation officer. He is a member of the IHBC technical committee. References 1The Control of Damp in Old Buildings, SPAB Technical Pamphlet 8 2 Understanding Dampness: effects, causes, diagnosis and remedies, PTrotman, C Sanders and H Harrison, BRE, 2004 3 Diagnosing Damp, R Burkinshaw and M Parrett, RICS, 2003 4 Damp Buildings, Old and New, Giovanni and Ippolito Massari, ICCROM, Rome, 1993 5 Analysis of Rising Damp, Digest 245, BRE, 1989 6 A Stitch in Time, DWrightson, SPAB/ IHBC, 2005 7 French Drains, Ian Hulme, IHBC Technical Committee The concept of the French drain is to intercept and reduce moisture around the base of external walls. The installation of a French drain involves excavation of a trench (commonly 600mm deep x 400mm wide) around the perimeter of the building to take a continuous, perforated land drainage pipe. The trench is normally positioned against the building or in a convenient position close to the perimeter. It is backfilled with a suitable gravel to allow free drainage and encourage evaporation of moisture from the trench or the base of the wall. Conservation professionals generally favour French drains as a method of tackling damp at the base of historic buildings due to the minimal impact on the building’s fabric. However, there may be important archaeological and structural considerations to be considered in a particular case. Ian Hulme’s guidance note (an IHBC technical sub-committee paper) on French drains is available through the IHBC website. Conservation professionals, faced with a scenario where rising damp has been offered as a cause but suspicious of or disagreeing with a proposed remedial solution, may want to investigate and negotiate. But they will remember that any standard remedial works can be highly destructive, can simply mask the problem and ultimately fail to address the cause of the moisture ingress. If the building were listed, most standard remedial Established for over 160 years LS Longden has a reputation for quality and traditional craftsmanship.The product has developed significantly over time to include modern performance characteristics meeting today’s technical requirements for fire resistance, sound reduction and security. For a comprehensive overview on how LS Longden can assist with your restoration or conservation project requirements, please contact us now. Tel: 0114 270 6330 E-mail: [email protected] www.lslongden.co.uk 55 Parkwood Road, Sheffield S3 8AH SOLID TIMBER BESPOKE DOORS LSLongden_Context_halfad 16/5/06 2:49 pm Page 1
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