Roof Drainage Improvements
This autumn roof drainage improvements have been carried out on the Guildhall Square side of the museum building. Two of the original downpipes have been replaced with new larger diameter pipework and two new gutter boxes have been installed at roof level.
It has long been realised that the original three inches diameter downpipes while hydraulically adequate were prone to frequent blocking by roof debris causing water to overflow the gutter boxes and spill down the walls of the buildings. This has resulted in damage to plaster and decoration inside the Tavistock Museum and the Subscription Library. The dropping of twigs on the roofs during the nesting season by several families of jackdaws who live around the Guildhall Square has added to the problem. The new downpipes are 100 mm (4 inches) in diameter which is almost twice the cross-sectional area of the original 3 inches diameter pipes thus allowing the passage of roof debris which would otherwise accumulate to block the rainwater system. The difficulty of removing debris by hand from the original gutter boxes at heights of 7m and 5m has also been addressed. It will be easier to removal any debris collected from the new gutter boxes and additionally there are open ends on the downpipes which will allow rodding and/or jetting.
Listed building consent for the scheme was obtained by Tavistock Museum and Tavistock Subscription Library (architect Stephen Whettem). The construction work was funded and project managed by Tavistock Town Council. The contractor was A.D. Williams and sub-contractor DFS Roofing.
The images to the right show the 7m high down pipe before and after replacement.