Brick mortar repair is work known as tuckpointing. It is the process of clearing out any crumbling mortar from between bricks and reapplying it to reseal the joints. Letting mortar deterioration get out of hand can eventually lead to further brick damage as well as moisture buildup in walls behind the brick. For this reason it is important to repair it as soon as you can. It is not a difficult job provided you do not let it get so out of control that it requires a bigger fix. Gather up your materials before beginning and choose a day offering pleasant conditions to do the job.
The first thing to do in the process is to clean out all of the crumbling mortar away from between the bricks. Take your hammer and tap the chisel firmly into the loose mortar. Anything that is loose needs to be removed. Tap into the solid mortar about ½ inch. After the biggest pieces of crumbling mortar have been removed in this manner, hose out the joints with either a high-powered jet from a garden hose or a medium jet from a pressure washer. In brick and mortar work there are both vertical and horizontal joints. Clear out the vertical joints first.
In the wheelbarrow, pour in the dry mortar mix. You may not have to use the whole bag depending on how many joints you have to fill. Follow the instructions, but in general, slowly add water, mixing it with the hoe until it is evenly mixed about the consistency of cookie dough. You don’t want it too runny, so add water slowly. Dab a small amount of mortar onto a scrap piece of cardboard. It dries very quickly there, so you will learn its final color. If it does not match the original mortar, you can add some mortar coloring until it does. Keep testing it on the cardboard before you apply it in the joints.
Applying the Mortar
With the hose, mist the brick to wet it down, not to soak it. Filling the vertical joints first, scoop an amount of mortar into a joint, smearing it in a downward motion, drawing out the excess mortar as you do. When the joint is filled and flush with the brick, finish it to match the original pattern. This is the process of carving or depressing the mortar joints in a discernible manner. You can either use the tip of the trowel straight on, turned to one side, or you can use a small piece of pipe or dowel to round out the joint concavely. Each time you fill a joint, finish it.
After the bricks have been re-mortared, keep the joints moist for several days by misting them lightly. When it eventually dries, go over the entire surface with the sturdy brush to clean up any mortar residue. Check all of the joints you repaired to ensure the mortar has properly adhered.