Many projects, especially those involved with brick pointing, call for the addition of drainage cavities. Such elements help to protect the building and masonry walls from the damaging effects of moisture penetration. Thus, one of the most important aspects to these cavities is that they properly drain moisture away from the masonry. At Abbot Building Restoration, our experts understand precisely what it takes to ensure your masonry work is best protected. Here, we delve more deeply into the world of drainage cavities and what you should know.
The Purpose
As mentioned, the overall purpose of the drainage cavity is to drain off excess water. The goal is to drain the water before it has time to penetrate the interior of the masonry. This task is easily accomplished by keeping the cavity clean and clear of excessive debris and fallen mortar.
For proper wall construction and to minimize mortar fins, bridging, and droppings, cavities should be nominally 2” clear. This gap, or space, serves as a trap for water and keeps it from penetrating into the surface.
How clean does a drainage cavity actually have to be?
As long as the cavity allows water to drain to the flashing material to avoid damage to the masonry wall, it is clean enough. Only when the operations and functions of proper draining are obstructed is cleaning excess mortar droppings or protrusions necessary.
It is important that the key members involved in the project, including the building owner, architect, and contractor, agree upon setting realistic expectations for the task at hand. It is to be expected that mortar droppings and protrusions may partially obstruct the drainage cavity. However, it is typically neither cost effective nor necessary to remove these obstacles to allow for proper drainage.
For more information about masonry restoration in Massachusetts and brick pointing techniques, contact Abbot Building Restoration at 617-445-0274. Since 1936, our company has proudly served the Greater Boston community by providing expertise, trustworthy advice, and superior craftsmanship.
