This end cottage on a row in Lancashire underwent refurbishment relatively recently. The building is at the low point of a gradient between the road and other cottages, such that rain water will gather and pool against the porch walls. Improper use of modern materials during the previous refurbishment caused moisture to become trapped. We undertook a number of works to correct the issues and to help prevent water from reaching the building.
There are signs that a pitched roof porch once stood in the place of the current entranceway. The stone lintel over the internal front door had visibly split. Furthermore, it provided minimal bedding for load transfer onto the stone side walls. The mortar used throughout the porch was a non-porous cement, trapping moisture in the stones.
Due to the small working area we needed to carefully support the existing lintel – and the stonework above – using temporary acrow props and strongboy masonry supports. We removed and replaced with a new stone lintel that provided sufficient overhang onto the side walls.
It was a 3 operative process to lift the new stone into position. We bed this in a porous lime mortar and repointed the internal exposed stonework with an identical lime mix used for the exterior.
Lime Repointing to Porch
The external pointing to the Porch was cement and as such was preventing moisture from evaporating. Trapped moisture may damage the stone instead as it tries to evaporate via the next porous material. Cement based pointing will harden and crack over time, which is when water and freezing begins to create more damage.
Using a pure lime and sand mortar mix is a consistent standard within heritage works to limit masonry damage, providing a porous mortar which allows for the flexibility and evaporation of moisture.
We deep pack lime into the joints as opposed to an overpointed 3mm thick cement. This offers good protection and bedding for masonry where water may have washed out the existing mortar. There is a period of monitoring the lime as it carbonates, to sheet and protect – as well as keeping moist – prior to brushing back the surface once ready.
Due to the tarmac passage to the row, we created a French drain to prevent the water run off getting to the stonework. This works as a pea-gravel soakaway to the drainage point in order to take water away from the building.
Although the tiled step does not appear to be causing a significant issue, we believed that it could be trapping moisture and as such we replaced with yorkstone paving. This enabled our team to create a fall away for water and aesthetically improved the cottage in keeping with traditional materials.