Brick is a wonderful building material that is beautiful, ages gracefully, and appropriate for a variety of applications from chimneys to walkways. It requires a little care to preserve it, but compared with other siding, walkway, and patio surfaces, the requirements are modest.
If you live in a climate wherein rain is a constant during the spring and have brick walkways or patios, you are probably familiar with the slippery algae growth that makes navigating them downright hazardous.
Algae on brick is as slippery as trying to walk on ice, especially in areas where the algae has optimum conditions for growth. A combination of moisture and shade is most conducive to growing a fine crop of algae, especially during the late winter and spring months.
The easiest cure for algae, if possible, is to eliminate as much of the shade as practical. By increasing exposure to sunlight, you can cut the incidence significantly. In the summer, it's much less an issue as warmer, drier temperatures inhibit growth.
However, there are areas in the garden that are delightful because of their shady, moist corners such as near water features or paths on the north side of your home. To be rid of the algae or moss in such areas is a bit more problematic. To minimize walking hazards, you can use a diluted solution of household bleach to target the algae and moss. If the area is fairly small, it's both cheap and simple to use. For larger areas, an algaecide would be more appropriate. There are non-copper based algaecides that are extremely effective and biodegradeable so they have a minimal impact on the environment. A pond supplier can help you select an algaecide that will work on hardscaped surfaces around your home.
The white deposits that occur on brick walls and flower pots are from the mineral salts contained in the clay. When brick is exposed to wet winter weather, salts are leached from the clay and then dry on the surface. Different bricks effloresce differently depending on the composition of the clay. The mortar used to cement them together may contribute as well. Typically, it's short lived; rain generally washes it away, so treatment is not usually necessary.
Painting brick is not recommended because brick is fairly porous, which makes removal difficult. It might be worthwhile hiring someone to remove the paint. Surfaces painted before 1980 should be tested for lead, which require licensed abatement by the EPA. Because brick is so easily damaged, a professional is better equipped to remove the paint without discoloring or ruining the brick underneath. If it's been painted once, consider repainting.
There are brick wall treatments designed to repell water, which sounds like it might be a good idea. Weigh application carefully; it could cause unintended consequences like frost damage or unexpected runoff that could lead to other problems. Also, most treatments have a limited life expectancy, so the benefit should pay for itself. There are products available that are effective and environmentally friendly if a water repellent is right for your brick surface.
You may have noticed brick walls that are a peculiar orange color and don't look quite right. Chances are they have been pressure washed by someone without brick cleaning experience. Pressure washing brick is best handled by professionals who have experience washing brick walls and patios. Brick is porous and comparatively soft, so washing with a little too much pressure can easily damage the surface. Mortar has different compressive strengths so knowing the type of mortar makes a difference too. A specialist can tell the difference between mortar and brick types and moderate their cleaning process for your particular project.
If you do hire a professional, make sure you run them through a qualifying process to make sure they know what they are doing. Check with licensed a masonry contractor for recommendations, then check with the Better Business Bureau to make sure there are no outstanding complaints. Ask for past project addresses and look at their completed work. Talk to the homeowner and find out if they were satisfied with the workmanship. Obtain guarantees in writing before work begins. If they mess up your home's exterior the cost to repair could be extremely expensive, so it pays to be cautious and know precisely with whom you are working.
Find a masonry contractor for brick and stonework in your area.