Match Brick Mortar Color

The person who tuck pointed this brick at the old sardine factory in Bass Harbor, Maine ruined it. He was supposed to match the white hydrated lime and use the correct sand. Copyright 2025 Tim Carter

Match Brick Mortar Color - It Starts With the Sand

You may not know this, but I received a bachelor of science degree in geology many moons ago. I was fascinated by the topic, and it helped me build houses and buildings that would not fail. Hydrogeology, the study of groundwater, and continental glaciation were two subjects that have allowed me to solve wet basement problems for thousands of homeowners like you.

One of the things I discovered in my college years is that normal sand you find anywhere is nothing more than very tiny pieces of rock. Some sand is quite pure like that you might find on Siesta Key in western Florida. Many call it sugar sand.

Most sand is comprised of different small pieces of rock. These miniature boulders are often different colors. Each grain of sand is no doubt a very small piece of a specific mineral. Black particles might be biotite. White sand might be quartz. Orange particles might have originated from a sandstone with a high iron content.

I live in central New Hampshire. The sand that’s used to combat ice on roads sparkles in the sun. The glitter is caused by very tiny flecks of mica. It gorgeous to look at on a sunny day.

I share this background with you for a reason. You may not have ever given much thought to how bricklayer’s mortar is made. Standard mortar is a combination of three ingredients:

• sand
• powdered Portland cement, lime, and some other ingredients
• water

Sand is the most abundant ingredient in the mix. The powdered cement and lime are the glue that holds the sand together and allows the mortar to bond to each brick, concrete block, or rock. Common sense tells you if you just got sand wet and laid brick with it, the brick would not bond to one another.

Masonry buildings older than 150 years didn’t have Portland cement in the mortar. The expert masons of old just mixed hydrated lime with the sand. They added just enough water to make the mortar mix the consistency of apple sauce.

When you mix the three ingredients above to make fresh mortar, the cement and lime coat each grain of sand much like adding beans to a meat chili. The color of each sand particle is hidden by the gray cement/lime coating.

This is why when you look at a brand-new brick or concrete block wall the color of the mortar is uniform. It’s almost always some shade of solid gray.

Mother Nature removes this thin coating of cement/lime paste over time exposing the sand color to your eyes. Look closely at old mortar and you’ll see individual grains of sand at the surface. The mortar color on old walls is created by the combination of all these tiny different pinpricks of color plus the cement/lime paste that you can see in between the particles of sand.

Your job, or that of the workman you hire to tuck point your brick, is to take time and find sand that matches the sand in your existing mortar. You need to match both the color and grain size.

Start your search at the closest gravel or sand pit near your home. Think of how hard it was to get sand to your house all those years ago when it was built. The bricklayer didn’t want to pay to have sand transported great distances if he didn’t have to.

One exception might be if you live in Cincinnati, Ohio. The best bricklayers used a very special silky sand available at the now-closed Rack Sand and Gravel pit.

This body of water is the abandoned Rack Sand and Gravel Pit in Cincinnati. The top surface of the water in the pit represents the level of water in the continental glaciation deposits that underlie the entire Mill Creek Valley. Unfortunately, it's probably very polluted by all the industry that's close to the gravel pit. Image Credit: Google Maps

This rare sand was fine-grained and had a tiny amount of loam in it. It made a delightful mortar that was easy to work with and produced stunning mortar joints.

Once you have the correct sand, you now need to concentrate on matching the correct color of the powdered cement and lime. Should you have an old building like the old sardine factory in Bass Harbor, Maine, you know you’ll just have to use pure hydrated lime. It’s a magnificent mortar ingredient that’s been used for thousands of years. Lime produces an off-white mortar.

The patient person mixes and tests the mortar before committing to using it. You mix some up, lay a few bricks, and let them sit for a month. At the end of the wait period you do a light acid wash on the mortar to replicate what takes Mother Nature thirty years to accomplish. The acid wash removes the thin mortar paste from the sand at the surface.

You can then see if one of your batches matches the existing mortar you’re trying so hard to match. Yes, I know this is lots of work, but who wants their house to look like it has a large facial scar running across the brick walls or the chimney?

I know I don’t!

Column 1596