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6 min read
Mixing lime the slow way
Why we slake our own putty, wait three months to use it, and never reach for cement.
Putty, not powder
Most of the walls we work on were laid in lime, and they still want lime. Cement is harder and quicker, but it traps water. In an old wall that water has to leave somewhere, and it usually takes the stone with it.
So we slake our own. Quicklime goes into water in a steel bath in the yard, it boils on its own, and the putty sits under a skin of water for at least three months. The longer it waits, the creamier it gets.
Knocking it up
On site the putty is beaten with sharp sand until it holds a ridge on the trowel. No additives and no colour from a tin. The colour comes from the sand, so we match it to what is already in the joints.
It is slower work. A pointed elevation can take a week longer than it would with modern mortar. In fifty years it will still be breathing, and it can be raked out without hurting the stone around it.
