repoint your crumbling mortar

I’ll huff and I’ll puff

The three little pigs where probably more concerned about the big bad wolf, than taking care of their brick house Real brick homes, however, require some periodic maintenance to keep them protected from the huffing and puffing of the weather. As a clay product molded and superheated to dry in a kiln, most bricks have amazing durability. The fact that some two-thousand-year-old ancient Roman brick roads are still being used today is testimony to their strength. In modern structures, bricks are often used over and over again and some bricks are worth more used that they are new.

Unfortunately, the mortar that holds bricks together is not always so long-lasting. Manufactured from cement and sand most modern mortars are very strong when they are initially used but, they are susceptible to the ravages of time. Weathering and acid rain can erode mortar and cause it to loose strength, crack and split away from the brick. Correcting this problem should be considered a part of the normal maintenance of a brick building.

Inspecting your Brick

The first step in maintaining your structure is to do a thorough inspection of the brick walls. Mortars usually start to go bad in 30 to 40 years but a lot also depends on the quality of the original mortar used and the direction of the worst weather exposure. Look for dirt and grime that has accumulated over the years.

Look carefully at each mortar joint for cracking, checking, and splitting. Make sure the spaces between the bricks look good. Test the integrity of the joint with a nail or small screwdriver. Is the mortar hard and well adhered to the brick or is it flaking away and soft? Will your screwdriver leave marks in the mortar, or is it as hard as concrete? One of the first symptoms of mortar problems is that it will become soft and weak and/or brittle.

When you poke it you will either find the mortar falling easily away or chipping and brittle like hard candy. Sometimes the heating and cooling around a chimney will cause the mortar to actually turn into a soft powder. Wind and acid rain can also wear away the mortar and create a deep groove where the mortar joint used to be. These are all signs that you need some repair work.

Repairing your Brick Mortar Joints

The repair process starts with a thorough cleaning of the brick. Rent a pressure washer and pressure clean both the brick and the mortar joint with a strong jet of water. Hand scrubbing and cleaning can also be used but involves a lot more elbow grease. The next step is to repair the mortar joint.

This is called re-pointing or re-tucking the joint. It begins by removing the bad mortar so that you can create a good strong surface to bond your new mortar repair too. You can do this with a heavy wire brush, a hammer, and a coal chisel or a grinder another cleaning tool. The secret is to chip or brush away only the weathered mortar. Good masons just like good dentists develop a feel over the years for how deep to go but, the key is to remove the weathered mortar back to a point where the original mortar is strong and hard again.

Be very careful not to damage the surface of the brick in the process. Removing the old mortar sometimes involved some hard work. Brushing, grinding and chiseling the mortar joint will deepen the mortar joint groove between the brick. If you don’t get back to good mortar your repairs will have nothing strong to adhere to. When the hard work is done the next step is to paint the exposed joint with a commercial bonding agent. Bonding agents can be found at most hardware stores or any masonry supply company that sells brick.

Using a bonding agent is an optional step but it helps create a better bond between the new and the old mortar. Finally, you need to mix up a good batch of strong mortar. Pay the extra money for the best quality you can find. Some masonry supply centers even sell a special re-tucking or re-pointing mortar mix. After you mix the mortar you can apply it into the cleaned mortar joint using your fingers or a mortar strike. This is a small tool that the professionals use to make their mortar joints.

The best method is to lay in the mortar with your hands and finish it by dragging your finger across the joint so that it is slightly depressed below the level of the brick. A word of warning, however, be sure and wear some form of gloves or hand protection as bricks and concrete will wear down your skin. Mortar joints vary in size and depth. Some mortar joints are never finished and you will see huge globs of mortar spilling over the seams between the bricks. Regardless of the type of joint, the key is to remove the weak mortar and replace it as carefully as possible with a new stronger mortar.

After the mortar dries you can clean any mortar that has spilled on the brick with an acid wash. Most masons use muriatic acid (a diluted form of hydrochloric acid) which can be purchased again at most masonry stores. This acid will dissolve the mortar and leave the brick clean. Be careful and be sure and read the directions because muriatic acid is very powerful and can burn you or eat holes in your clothing. When you are done acid washing be sure and wash everything well with large amounts of water. You are now done with your masonry repair.


Now if you have done the repointing project properly you will have restored both the strength and the beauty of your brick wall. You have removed the bad mortar and replaced it with good stronger new material. You will be better protected from the huffing and puffing of the weather and like the three little pigs you will discover that brick houses are the best.

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