When it comes to cleaning, repairing and sealing, the techniques and materials used for brick and stone are the same.
Efflorescence, salt air, stress cracks, and severe weathering can be threats.
Stress cracks typically occur in mortar joints rather than within the brick or stone itself. If stress cracks in mortar are the problem.
If the problem is a cracked or broken stone or brick, it can be removed by chiseling out the mortar surrounding it. With the mortar out of the way, the brick or stone will have room to expand and can be easily broken up using a cold chisel along with a small sledgehammer. A new brick or stone can be inserted into the hole to replace the one removed. The brick or stone should be surrounded with mortar for a solid fit.
Applying a sealer can minimize brick or stone damage from salt air and severe weathering. It can even work to prevent efflorescence. However, just as with concrete, brick and stone should be thoroughly cleaned before applying a sealer.
If you've come up against a stone wall trying to clean brick or stone in patios, walkways, walls, or a chimney, then you really should read on. The three most common masonry-cleaning problems are:
- Fungus, moss, and mildew: One quart of household liquid bleach mixed into 1 gallon of warm water applied with a stiff bristle brush usually takes care of these guys. (Don't forget to rinse the solution off with clean water.) However, sodium hypochlorite, the active ingredient in bleach, might not dissolve large masses of these types of growths. In such cases, scrape off as much of the crud as you can with a broad-bladed putty knife (or wire brush). Then, scrub on the killer mixture.
When trying to eliminate fungus, it's the bleach that does the job-not the elbow grease. Make sure you give the bleach plenty of time to work before scrubbing and rinsing away. If not, fungus spores will remain and can grow back quickly.
- Oils, soot, and mineral residue: Oils, soot, and white, powdery mineral residue pose a slightly more difficult problem. Characteristically, they are embedded more deeply into the pores of the masonry than moss and mildew. You need a solution of 1 part muriatic acid to 9 parts water to get rid of these unwanted guests. Add the acid to the water and apply the solution -- allowing it to set for about 15 minutes. Then use a bristle brush to clean the affected area and rinse with fresh water.
- Paint: Sandblasting, wash-away or peel-off paint removers, hand or electric wire brushing, muriatic acid washing, and power washing are just a few of the ways that you can remove paint from masonry. Sandblasting or wire brushing is hard, messy work, and paint removers sometimes create more mess than they eliminate. Instead, we recommend power washing. A commercial power washer can be rented for about $50 per day. It's easy to operate, mess is kept to a minimum, and you don't have to be a chemist to make it work. A power washer might work fine on the outside of your home, but all of that water could wreak havoc on the inside of your house. Therefore, when it comes to removing paint from brick or stone, your best bet is a chemical stripper such as Peel Away.
In addition to cleaning your masonry, you need to repoint the brick mortar from time to time as it shows signs of deterioration.
When a new mortar patch dries and doesn't match the existing shade or color, have a small amount of latex paint color matched to the existing mortar. Use an artist's brush to paint the new mortar joints. No one will ever know where the existing material ends and the new work begins -- including you.