H+R were instructed to undertake detailed timber condition investigations of this large historic timber framed barn for one of the Oxford Schools. The intention was to understand the structural integrity of the barn as the idea was to construct an independent structure within it. The Structural Engineer involved required further strength grading information of the existing historic timbers, which included species identification, as well as a narrative and suitability assessment of remedial works conducted in the past.
The investigation involved extensive decay detection drilling, physical probing for pockets of decay, assessment of historic jointing techniques and modern remedial intervention, as well as visual assessment of timbers for strength grading purposes which include extraction of timber samples for species identification later in the H+R laboratory, and a survey of the external facades to note external defects that could result in internal decay. Colour-coded annotations of timber components identifying species (preliminary indications, elm/oak), historic/modern, defective/decayed were annotated onto CAD drawings during the investigation, and all available dimensional data was recorded.
How we solved the problem
The colour-coded annotations provided the design team with an accurate map of defective or decayed timbers, as well as a visual narrative of intervention since original construction. Significant decay was identified, especially to the sole plate of the timber frame; a direct result of inappropriate cladding detailing and exposed masonry plinth heads. A variety of other issues were also noted including unsympathetic and potentially dangerous modern intervention. A full schedule of repair was included within the report accompanied by a selection of suitable traditional timber repair details that could be incorporated into the works