Brick is the backbone of many houses, also fireplaces, walkways, patios and barbecues — all exposed to the weather year round. The brick can take it. The mortar that holds them together is another story. But if you catch its deterioration in time, simple fixes can solve the four main problems.
Fixing mortar joints. Like grout between tiles inside, mortar is the weak link outside because most mixes aren't as strong as the surrounding brick. And while brick is consistent, produced in factories, mortar varies. It's often hand mixed not too precisely and applied in a variety of weather conditions that can alter its strength.
Hairline cracks are the first sign of trouble. As they spread, moisture gets into the joints and increases the erosion. Wider cracks eventually connect and mortar that's waterlogged starts to crumble and break away in small chunks.
As you scrape the joint with a trowel, don't try to save bad mortar with a light touch. Dig in. If you leave loose or spongy sections they will disrupt even the most careful repairs. For new mortar to take hold, damaged joints should be excavated at least as deep as they are wide. Before applying fresh mortar, sweep or blow out any debris, and mist the joints with water. Old, dry mortar will pull water out of the new mix and weaken it.
Mix a small batch to start- until you see how quickly you can fill and finish the joints. Spread the mix on a float or board, hold it against the wall just under the joint, and push it in firmly with a small trowel. Finish by compressing the mix to create a slightly concave shape- with a pointing iron or even the handle of a small paintbrush.
Fixing flashing. Where brick meets other materials, particularly between chimneys and roofing, the joint is closed with two layers of flashing. When you're talking to contractors, the description is flashed and counter-flashed. The first layer tucks under the roof shingles, covers the crucial seam and extends up the wall where it is bent and mortared into a joint between courses of brick. The bottom edge of the second layer covers this seam, and its top edge is mortared in the same way higher up the wall.
Watch out, particularly on reroofing jobs, for a slapdash detail - a piece of aluminum pasted against the brick with roof cement. It won't last. And when the top edge pops loose water will run behind the flashing into the roof.
Fixing erosion. On walkways and patios the common problem is erosion, mainly at the edges where water washes away layers of supporting sand. A soldier course (brick set upright) can help. An easier option is to install plastic edging like Pave Tech's Brickhold. (See the system online at pavetech.com.) Typically, these borders are concealed below the surrounding grass and prevent erosion by holding back the brick and the sand base. Many have slots so pieces can be bent into gentle curves- if you want to tackle the job of breaking right-angle brick to fit.
Fixing efflorescence. Milky splotches on brick siding are salt deposits brought to the surface by water. It's the same process that leaves white rings on your boots after trudging along salted slushy sidewalks. Remove light deposits with a broom or stiff brush. Heavier deposits require scrubbing with a solution of muriatic acid (observe label cautions) diluted 10 to one with water. That's the easy part. If the deposits return you need to identify and stop the flow of water that's bringing them to the surface. It could be from condensation, a plumbing or roof leak near the wall, or a leak in the gutter system.