Repairing the brickwork at Blickling
This spring we’ve been busy carrying out conservation work at Blickling that has involved repointing and repairing brickwork around the Hall.
Why were the repairs needed?
The brickwork was last repointed with a cement mortar in 1967. After 50 years, the time had come to carry out repairs.
So why haven’t we used a cement mortar this time?
One of the major causes of damp in historic buildings is linked to the use of cement pointing. This became popular in the late 1960s and 1970s.
A solid brick or stone wall, built with lime mortar, needs to breathe. It loses its moisture content through the mortar joints and if this breathability is blocked through the use of cement, the wall immediately starts to get wet.
Water then becomes trapped and the only way for it to get out is via the brick or stone. In winter, the damp brickwork then freezes and the bricks start to crack and break into fragments.
What have we been up to?
We’ve been working with the team at Cliveden Conservation, who have removed the old cement mortar, along with any damaged bricks. These bricks have then been replaced and we’ve been repointing with lime mortar.
What’s so interesting about the lime mortar we’ve used?
We believe it’s the first time we’ve used hot mixed lime mortar on site at a National Trust site in the East of England.
Hot mix mortars are those where quicklime, sand or aggregate, are mixed together and the moisture in the sand allows the quicklime to start reacting before water is then added. The quicklime is therefore slaked and mixed in the same operation.
Historic records show that hot mixing lime mortar would have been the norm, with lime putty only being used for the fine plaster work.
So, take a closer look at the brickwork on your next visit, will you be able to see the difference between the old and the new? It won't be long before the Norfolk weather helps to blend the new mortar in.