After several trials on a small part of the stone wall at the back of the house, to determine the type of sand, colouring and brushing technique, we were ready to start grouting the rest of the house. As for the rest of the house, and in order to maintain the breathability of the walls, we used lime to mix with the sand rather than regular cement.
Grouting is a rather long and tedious work but it is the last touch on a stone wall and depending on the materials and techniques used, the result can be drastically different. We tested two different types of sand because of their colour and caliber (one finer than the other); both are locally sourced. We decided to add a little bit of natural colouring to make the grout a tad yellow so it would match some of the moss hues one can find on some of the stones. The sand caliber is important as if it’s too fine, it may not adhere to the stone as well in the long term; small fracture lines may appear where the grouts meet the stones and moisture or water may start infiltrate.
The masons started with the stone wall that covers the rainwater cistern at the back of the house. This wall is not seen very much from the road and therefore they could practice and fine tune the technique before moving to other more visible walls.
The grouting mix is pushed with a trowel in all the cracks around the stones. It is then left to dry for a few hours before brushing starts. Depending on the type of brushing (hard, soft, circular, etc), the appearance of the grout will vary. The brushing enables to reveal the outline of each stone, push the grout mix in all the small little holes for better bonding and give a certain look to the grout itself. Some stone walls have very thick grouts where the stones are half covered by the grouts. We chose to have our grouting done so that the stones would clearly stand out.
The picture gallery below shows more pictures of the grouting. The first main wall to be done was the South East facade and while the grouts are not completely dry yet, the end-result is already amazing.
