Repointing a stone wall
Preparing the wall
First you will need to remove any existing pointing or render. This is best done with a pneumatic hammer and an air compressor which is approximately 50 times faster and easier than doing the job manually, and doesn’t leave you with terrible wrist problems. The hammer and air compressor can be hired or bought.
Next, your stone wall will need cleaning. Even if the wall looks clean you should do this, otherwise you will be pointing onto a dusty surface. There are two main methods available to clean a stone wall - sandblasting and high pressure washing.
Sandblasting is very effective, but also time consuming and dirty, requiring a mask and protective gear to be worn because of the large amounts of dust and sand flying around. It is a very good way of removing decades and centuries of grime from the surface of the rock. You will need an air compressor and a sand-blasting attachment, and some ’sand blasting sand’ - your building suppplier will understand if you ask for ’sable pour faire le sablage’.
Sandblasting has the other advantage that it can be used indoors where high-pressure water washing may be impractical. (Read on …)