Masonry cavity walls consist of two wythes of masonry separated by an airspace connected by corrosion resistant ties. The internal drainage cavity is designed to intercept any water that penetrates through the exterior wythe. Flashings, weep holes and waterproof membranes are used at the base of the cavity to direct water out of the cavity and prevent water from getting into the building. A 1" minimum clear space is required by code.
- Design of Concrete Masonry Noncomposite (Cavity) Walls
- Water Penetration Resistance - Design and Detailing
- Water Penetration Resistance - Materials
- Water Penetration Resistance - Construction and Workmanship
- Brick Masonry Rain Screen Walls
Mortar Fins & Droppings
Mortar droppings from the construction process can fill or bridge across drainage cavities, clog weep holes and prevent the escape of water from the cavity. Mortar fins that bridge the cavity, usually at wall ties, can act as conduits for water to the interior wythe. Masonry cavities should be built free of excess mortar that may impede moisture flow or permit water to saturate the backup.
- Why are Mortar Droppings a Problem?
- Mortar Fins' Maximum Size
- Grouting Concrete Masonry Walls
- Reinforced Brick Masonry - Materials and Construction
Mortar deflectors or nets are often used at the base of cavities to catch mortar droppings which would otherwise clog cavities and weeps and prevent escape of water. Many materials are used for this function including netting or mesh of various types that catch the mortar and prevent it from settling at the base of the cavity. Pea gravel is also traditionally used which, being larger than weep tubes, holds the mortar away from the weeps and keeps them clear. This is a less effective method and mesh or net is preferred.
Companies Offering Drainage Materials, Prefabricated
|Mortar Net Solutions||Portage||IN|
|Advanced Building Products, Inc.||Sanford||ME|
|County Materials Corporation||Marathon||WI|
|Masonry Accessories, Inc.||Orlando||FL|
|Raymond Builders Supply||Geneva||OH|
|Thompson Building Materials, Inc.||San Diego||CA|
|Waldo Bros. Company||Boston||MA|
|Keene Building Products||Mayfield Heights||OH|