Dock Museum, Barrow – Fixing Water Seepage Through Mortar Joints
Barrow Dock Museum is one of the most popular visitor attractions in the Lake District.
Since 1994 it has been located in a building constructed over an original Victorian dry dock. The original sandstone block construction of the dry dock has remained exposed as an architectural feature. However water seepage through the mortar joints had resulted in unsightly growth of mould and vegetation.
Waterproofing specialists JJ Metcalfe Ltd. were called in to provide a solution to the problem.
As the clients wished the sandstone block façade of the original dry dock to be maintained, the most obvious solutions (i.e. application of waterproofing slurry, or lining with a cavity drainage membrane) were not possible. Instead, JJ Metcalfe Ltd. proposed reducing the passage of water through the masonry by raking out the mortar joints and replacing the mortar with waterproof mortars from the Vandex range.
Work Carried Out
Access to the dock walls was complicated by their stepped shape combined with access difficulties to the lower dock floor. This was overcome through the use of safety lines and harnesses allowing operatives to transverse the dock walls without any risk of falling from height.
The dock walls were then washed using a high-pressure jet wash to remove vegetation and surface growth. The mortar joints were then raked out to a depth of approximately 40 mm and flushed out to remove debris.
In areas where water seepage had been noted to be particularly severe, Vandex Plug was trowelled into the prepared mortar joints to a depth of 10 – 20 mm.
All prepared mortar joints (including those to which Vandex Plug had already been applied) were then gun-pointed with Vandex Unimortar 1 or Vandex Rapid M. In total, 1200 linear metres of mortar joints were treated in this way.
When the site was re-visited one month after the works had been carried out the ground water seepage through the mortar joints had been addressed. The only seepage occurring was through the pores of the sandstone blocks themselves – which had been expected. The client was very pleased with the outcome and the visual appearance of the dock wall had been greatly enhanced.