Masonry refers to building construction using materials such as concrete, tile and glass blocks, stone, brick and brick veneer. In residential building, masonry is used to build house walls, landscaping structures, retaining walls and for design and decoration.

Mortar

Mortar is the paste-like substance used to bind the masonry materials. Similar to concrete, mortar is a mixture of cement, aggregate (usually sand) and water. Hydrated lime (a product of limestone) is often added to mortar to increase its workability and improve its waterproofing qualities. Generically white in color, mortar can be difficult to keep clean. Mineral pigments can be added to mortar for various shades of color.

 

As with concrete, mortar can contain various additives or “addmixtures” which lend different properties to the mortar base. One of the most common addmixtures is antifreeze, which allows masons to work in temperatures below freezing.

 

Antifreeze and other addmixtures can cause health problems for those with sensitivities to building materials. In these situations, avoiding use of addmixtures in mortar when constructing or repairing masonry is the safest option.

Masonry Blocks

Concrete blocks are sometimes called cinder blocks because cinders can be used as the aggregate to reduce weight and increase the insulative value. Concrete blocks are somewhat porous and sometimes absorb odors. Besides the standard smooth-faced variety, concrete blocks are now available with various textures, shapes and colors.

 

Glazed-tile blocks are made of clay and are relatively maintenance-free. They are available in a variety of shapes and colors and can be used for partition walls or load-bearing applications. Like ceramic tile, glazed-tile blocks are inert—but they can also be expensive. They are primarily used in commercial applications, but can also be used in residential construction.

 

Clear glass blocks are often used for accent walls and are popular for maintaining privacy without blocking light. Installation requires more care than other forms of masonry because glass blocks don’t absorb moisture and it’s difficult for mortar to adhere to glass. The blocks are sometimes coated with a plastic resin on the edges to improve bonding. This is covered with mortar after installation, so it’s doubtful that it would be bothersome to sensitive people. Glass blocks are available in a variety of patterns and sizes.

Stone

Stone can either be cut into very uniform shapes, or used in a rough natural state. Common varieties include: limestone, sandstone, granite, and marble. Stone provides a nice accent both indoors and outdoors, but softer stones are more absorbent and easily stained.

 

In general, the only danger in using stone masonry is if the stone contains an excessive amount of radon. Many stones contain a tiny amount of radon, but it tends to be trapped within the stone itself. So, indoor airborne radon from natural stones usually isn’t a problem—but in rare instances it can be.

Brick

Brick is made of clay and/or shale that has been fired and hardened in a kiln. Harder bricks are less likely to absorb moisture or odors. While bricks are not as hard as other ceramic materials—like some floor tiles that are fired at higher temperatures—they are generally quite inert.

 

Bricks are available in a variety of colors, sizes, shapes and textures. Although usually confined to outdoor use, they can be used indoors as well. A decorative wall indoors can be very attractive, but also difficult to clean because of the uneven surface.

 

Brick pavers are widely used for sidewalks, but they can also be used for driveways. They can either be set on a concrete base or on a base of sand. Brick pavers are available at many building-supply stores in a variety of styles.

Brick veneer

Brick veneer is popular on the exteriors of houses. With this construction method, a framed and insulated wall supports the building and the outer surface is protected from the weather with a decorative facing of brick.

 

Brick is a low-maintenance product, but it is not waterproof. A certain amount of moisture will pass through both the brick and the mortar. To prevent this moisture from causing damage inside the wall, it is imperative that a brick-veneer wall be designed and built so the moisture can escape back toward the outdoors.

 

Following these well-established guidelines when constructing brick veneer exteriors will prevent moisture-related problems down the road:

• Base flashing should be installed at the bottom of the brick wall to catch any water that penetrates and runs down the back side of the brick.
• Weep holes should be made in the brick at the bottom of the wall to allow the moisture to drain back toward the outdoors.
• A one-to-two inch air space should be created between the brick and the framed wall. The air space must be free of mortar droppings, which when wet can lead to hidden mold growth and rot in the house framing and insulation. Steel studs can be prone to rusting if they get wet repeatedly.
• Metal ties should be placed about every three square feet when framing the house which slope slightly toward the brick. If they slope toward the framing, water will run down them and wet the framing and insulation—again, resulting in possible mold and rot.