Thinking about brick masonry construction makes me wonder about ancient civilizations. It’s a wonder that thousand-year-old masonry structures still stand today. Can we learn how to increase the lifetime of our brick masonry structures from ancient civilizations?
The longevity of the Roman structures was due, in part, to their cement. Ancient Roman cement contained volcanic ash, which when mixed with lime and seawater created a mysterious composition that was resistant to deterioration. Romans understood the merits of their volcanic ash and shipped it throughout the Mediterranean. Today, the chemical properties or Portland Oregon cement mimic this ancient formula.
Surely, another key to Roman’s longevity of their masonry structures was their warm, dry weather, which rarely dipped below freezing. Damage to brick masonry and mortar occurs when temperatures drop below freezing and cause water held within porous bricks and cement cracks to freeze and expand, putting immense pressure on the bonds that hold the materials together. We need to protect our masonry from water to negate the effects of rain and freezing weather.
In the last thousand years, we’ve learned a few things about how to protect our brick masonry from water. We cover horizontal brick surfaces with cement crowns and cover our chimneys with caps. We also protect our walls with overhangs and drip spouts. Using sealers or paint to protect brick masonry is unwise, because bricks need to breathe. Simply covering bricks will trap water inside. On the other hand, treating bricks with a vapor-permeable water repellent will make them hydrophobic and resistant to water absorption.
With the development of hard, long lasting mortars, our temperate Portland, Oregon climate, and new methods to protect bricks from water, it’s reasonable to assume that our masonry structures should last as long as those of ancient civilizations. Only time will tell, nevertheless, a few hundred years is still pretty good!