Matching mortars by recognizing the fractal nature of geology

the fractal nature of stone to sand

Mortar matching is often seen as difficult to do, but once you understand that historic mortars primarily came from local sources, one need only look to the local geology including at roadside cuts to recognize the aggregates of a sand in their former condition. This is the wonder of the fractal nature of stone reduced to sand. And often the sand you seek is right beneath your feet!

Mortar ratios: How to measure void space in sand

The basic idea behind determining the void space in a sand is to determine the ratio of lime needed to adequately bind the sand without pushing the sand grains apart. In other words, how to make the strongest possible mortar by optimizing the lime portion.

A Portable Lab for Mortar Match Finger-printing of Your Local Geology

Portable lab trunk assembled on the truck tailgate for go-anywhere sand sieving and analysis.

Google Maps for mortar matching?! Go local when seeking to match historic mortars as the sand you seek may well be under your feet. If you need to go off site, look nearby. When the mortar analysis checkbox is clicked by sending away for a report that does not give you an exactly matching source (without relying on tweaks from pigments that may not be stable and will change the lime-sand ratio of a mortar and its working properties), your money is being wasted and your building is not getting the best treatment.

What you need to learn from a mortar analysis about aggregates and ratios

Sand is not sand is not sand. Often when people are having stucco or plaster application problems (although the same can happen with bricklaying mortar), it turns out the aggregate is to blame. In short, it is not as simple as accepting whatever is at the local masonry supply house. Nor for that matter if… Continue reading What you need to learn from a mortar analysis about aggregates and ratios

The strength of mortar: an introduction to lime mortar

The lime cycle from limestone to hydroxide (lime putty) and back to stone

Covering the differences between hydraulic limes or cement and lime putty, this is a summary of the importance of pre-mixed mortar, proper hydration before and after installation, and compaction of lime putty-and-sand mortars.