Colouring Mortar

To colour lime mortar, made from a mix of lime and sand, we can use traditional methods. These mixes were used for 'stopping', the outer layer of the mortar between the joints.

These recipes are:


Used for red stocks. Make a dry mix of one part grey lime to three parts of fine washed sand, ideally red in colour. Venetian red and a little vegetable black can be used to tint the mixture. After the stopping is applied, it can be washed with more red colouring.


Yellow stopping is made with one part grey lime putty and to three parts fine washed sand. These ingredients are mixed together dry and then sifted before being added to water with yellow ochre as a colouring. Yellow stopping does not need subsequent colouring with a wash.


Less common, black stopping can be made from grey lime, slaked and mixed with foundry sand, and sieved. This is added to water and coloured with a little lamp or vegetable black if needed.


In this case, use chalk lime, and either silver sand or marble dust. Chalk lime dries much whiter than grey lime. Marble dust gives a better colour than silver sand.


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