Ventilation bricks provide a mechanism for airflow through a masonry wall in an effort to limit moisture problems. In a totally sealed wall, especially in a well-built structure, humidity can build up and damage the masonry, causing bricks to chip, and creating other problems. The solution is adequate ventilation to keep air moving freely through the wall, which keeps the environment dry and structurally sound. There are a number of approaches to this problem, and ventilation bricks provide one option for moisture control.
These bricks include a lattice design with a series of small holes. They can be inserted periodically into the brickwork to provide room for air to move, at intervals determined by a designer. Contractors want to make sure the structure has enough airflow, without creating drafts or other problems. The wall itself can vent through small holes along the roofline, allowing warm moist air to rise and escape in a steady flow.
Holes in ventilation bricks are typically large enough to provide airflow even if scrap cement and other materials fall behind the brick. Animals cannot enter through the holes, although they can become a conduit for insects. In some installations, screens may be added to discourage insect visitors, or the bricks can be treated to repel insects. The free flow of air through the brick can prevent mold and mildew, which might cause human health problems in addition to damaging the brick. Proper ventilation can also help with temperature control.
Many designs are decorative to add visual interest. The ventilation bricks can be installed in a pattern which makes their function less obvious and makes them look decorative. It is possible to order custom designs, including bricks with specific patterns and stained bricks in an assortment of colors. They can be structured into the design plans to create a specific look and feel during the building process.
Older structures in need of retrofitting can have ventilation bricks installed during masonry maintenance and repair. Some older buildings have weep holes and ventilation tubes to handle moisture problems. These can be sufficient in some places, but ventilation bricks may offer better flow and control in the long term, especially after weatherizing, which tends to help buildings retain water by sealing off cracks and other sources of air flow. In cases where there are concerns about maintaining historic integrity, it may be possible to use appropriate salvage bricks or custom designs to keep the building looking authentic.