Lime Repointing a Victorian Terrace, Wimborne Minster

The problem

The owners called us about damp on an internal wall in the front bedroom. The damp was real, but it was a symptom – the cause was on the outside.

At some point in the 1980s the whole front elevation had been repointed in a hard sand-and-cement mortar. On a Victorian solid wall that is a slow-acting disaster. The soft handmade brick is more permeable than the cement joint, so every bit of moisture that gets into the wall now has to leave through the face of the brick rather than through the joint. Come a hard frost, it takes the face of the brick with it.

By the time we looked at it, forty-odd bricks had lost their faces and the joints were pulling away from the brick on the exposed side.

What we did

There is no quick version of this job. Every joint on the elevation was raked out by hand and with a properly guided tool – never an angle grinder, which widens the joint permanently and cuts into the arrises of the brick.

The spalled bricks were cut out individually and replaced with reclaimed stock from the same period, turned so the good face was outward. Then the whole elevation was repointed in an NHL 3.5 lime mortar with a sand matched to what survived at the back of the property, finished to the original slightly recessed profile.

The result

Five weeks including scaffold. The bedroom wall dried out over the following summer without any internal work at all, which is what should happen when you fix the cause instead of replastering over it.