Maintaining and Cleaning Brick, Block & Stone

  • Brick, concrete block and stone are used as sidings on veneer walls and are also built into masonry walls. Veneer walls are standard wood frame walls with a brick, block or stone facing for weather protection. The wood frame provides the structural support. Masonry walls, on the other hand, use the brick, block or stone as both the structural support and the weather protection.
  • Inspect your masonry chimney and any brick, block or stone walls twice each year. Look for chipped, cracked, loose, deteriorating and missing material. Any such problems should be repaired to keep water out of masonry material and from causing future damage.
  • You should also check the mortar joints for weak or crumbling mortar. Use an old screwdriver to test the mortar by scratching along the mortar joints. The mortar should be firm. If it crumbles easily, is cracked or has fallen out, have the mortar joints repaired or water will enter the joints and cause additional damage.
  • A white powdery substance that can form on the surface of masonry work is known as efflorescence. It is caused by moisture bringing salts to the surface. Efflorescence is common in new masonry work and can be washed off. If the condition persists, it may be a sign that water is penetrating the wall through cracks, faulty mortar joints or defective caulking or flashing around wall joints or openings. Have the problem investigated and repaired.
  • If you ever notice bulging sections or large cracks in either a veneer or masonry wall, have the condition checked by a professional contractor. It may indicate structural problems. 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.

Algae and Moss

  • 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 bio-degradable so they have a minimal impact on the environment. A pond supplier can help you select an algaecide that will work on hard scaled surfaces around your home.

Efflorescence Buildup

  • 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 efflorescent 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.

Waterproofing Brick

  • There are brick wall treatments designed to repel 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.

Pressure Washing

  • 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.

Masonry Advisory Council – For interesting information about Brick, masonry, & related product information. This is a useful site.