Public House, Wareham – Preventing Rain Penetration

Background

The “Old Granary” Hall & Woodhouse Public House is located on the River Frome in Dorset and overlooks the Purbeck Hills. The building had suffered from intermittent rain penetration problems during periods of heavy rainfall – resulting in damp patches appearing internally.

The main building has walls constructed from 450 mm thick solid brick. However the original river-facing gable wall had been replaced many years ago with a wall of cavity construction. Very porous bricks and lime mortar had been used to construct this cavity wall.

Investigation

Building restoration specialists, Timberwise, were called in to provide a solution to the rain penetration problem. They identified two main contributing factors:

The cavity trays fitted over the door and window openings were partially blocked and unable to cope with the extent of water ingress during periods of heavy rainfall.
Masonry absorption tests revealed the bricks and mortar on the external face of the cavity to be unusually porous. This would indicate that relatively large amounts of rainwater would be able to pass through the external wall and into the cavity during periods of heavy rainfall.

Solution – Waterproofing of the Brick Wall

The cavity trays were unblocked and cleaned to allow them to perform their original function.

Rather than rebuilding the gable wall (uneconomical) or applying a render (would destroy the aesthetic appearance), Stormdry Masonry Protection Cream was applied to the wall surface to prevent water ingress through the pores.

Initially Stormdry was applied to a small test area of the wall and allowed to penetrate. After four weeks the test area was examined and found to be identical in visual appearance to the rest of the wall (i.e. no darkening, surface deposits, or shininess). Masonry absorption tests showed that water was no longer able to pass through the porous masonry due to Stormdry’s water-repellent effect.

Following the successful test application, Stormdry was applied to the whole of the gable wall area. A later follow-up visit by Timberwise reported no further damp ingress and no visual changes to the building’s appearance