Lime Mortar Experiment (Masonry Repair Pt 1)
This video recorded while I was on "Introduction to Masonry Repairs in Traditional Buildings (P1)" by the Scottish Lime Centre.
This is an experiment to work out exactly how much binder you need to use to completely fill the air voids in the particular sand that you are using. Normally a 3:1 ratio is what you use = three buckets of sand to one bucket of binder is enough, because 33% of the sand is air pockets. But sometimes it can be as much as 60%. How do you know? You do this experiment.
We were taught to do this in the lime mortar workshop held in Scotland. Is it important? If you are using cement mortar its not that important because its so strong. However, if you are using lime as your binder and you want your work to last hundreds of years, it is.
It also shows you how to mix a large quantity of mortar by hand without breaking your back.
http://www.scotlime.org