While the first thought may be, “Won't those little holes let cold air in (or warm air out), the reality is these are the window's weep holes. They are designed and placed to drain water out of the window frame, while preventing airflow into your new pole building.
Weep holes are "openings placed in mortar joints of facing materials at the level of flashing, to permit the escape of moisture, or openings in retaining walls to permit water to escape," according to the Masonry Design Manual.
Condensation issues
Weep holes in windows provide an avenue for water to safely leave the window's frame. Without this clear path, the water remains trapped. Consequently, your views may be obstructed by foggy windows on a hot day as condensation occurs.
Weep vents play an important role in draining and ventilation and are installed during the construction phase of a building. They assist drainage by allowing water to escape the building envelope, improve ventilation by helping to circulate air, and can help prevent pests from entering the structure.
While they can provide an entry point for pests, covering weep holes in brick walls is a definite no-no due to the damage this can cause to a building's structure. Instead, high quality screens and covers can be used to keep vermin out whilst maintaining the utility of these very important openings.
Weep holes serve an important role in your home's drainage and ventilation, but they can also provide pests such as mice and cockroaches an easy access point into your home.
As an alternative to weep holes, most new construction will connect the drainage zone to a perforated drainage pipe located behind the base of the wall outfalling to a manhole.
Weep holes are often located at the bottom of brick exterior walls. They look like vertical gaps in the mortar joints between bricks. Because brick masonry is porous, water may penetrate the surface and get behind the wall.
“Not all properties have weep vents, especially old houses as they were built without cavities and weep vents and cavities have become popular over the last few decades as the building industry has evolved and we have become aware of moisture-related issues and building science improved,“ shares David.
Even if you used the code as a basis of the requirement for weep holes, you would be surprised to learn that weep holes were nor mandated in the single family code until 1983 CABO, mandated by the 1985 Kentucky Building Code. Home inspectors are calling out missing weep holed on house built before 1985.
Problems With Weepholes
If weep holes are left unprotected in brick walls they provide access to the wall cavity for rodents and insects. Swarming bees and European Wasps love creating nests in cavities.
The easiest way for pests to invade your home.
However, that is exactly the access that most pests have into most homes…and its all because of weep holes. Weep holes serve a good purpose for your home. They are designed to release unwanted moisture.
It's obvious that small pests such as cockroaches and spiders can crawl through weep holes, but vertebrate pests such as lizards, snakes and even mice can also squeeze through a normal weep hole.
As an air barrier contractor or installer, your understanding of some of these principles is critical to the durability and performance of these wall assemblies. Blocking a weep hole in a window can have catastrophic results in water damage for the building.
The Weep Vent should be spaced at no greater than 900mm centres to meet N.H.B.C guidelines, which state, “weep holes are recommended to be sited at every 450mm maximum with at least two per opening above all windows and doors.”
Without weep holes, water has only one place to go – inside your home's walls, leading to mold, rot, and unpleasant, expensive structural issues.
Weepholes shall be provided in the outside wythe of masonry walls at a maximum spacing of 33 inches (838 mm) on center. Weepholes shall be not less than 3/16 inch (5 mm) in diameter. Weepholes shall be located immediately above the flashing.
This research demonstrated that even under truly extraordinary conditions water rarely enters the weephole and even if it does it cannot be blown high enough up in the cavity to create internal damp problems. To understand why, it's important to look at the details of a correctly constructed cavity wall.
It is difficult to add weep holes after the walls are constructed. If the weep holes are drilled, they will typically puncture the flashing. This is true even if a special guide is placed on the drill. If the hole does not go all the way through the mortar then it will be ineffective.
Do I Need To Plug Weep Holes During a Flood? No. Unless your home is a submarine the exterior materials along with doors and windows are not watertight and will succumb to the flood waters.
The purpose of weep holes is to provide an outlet for water to drain and escape a building or structure. They can also assist in the ventilation of cavity spaces and relieve hydrostatic pressure from barriers such as retaining walls.
Your weep holes are an important part of your home's drainage and ventilation system, but they're also vulnerable to pest infestation. Cockroaches, rodents, and spiders can easily enter your home through these gaps in your brick cavity walls.
Why are there no weep holes? The reasons vary, but the house's builder forgot to include them, or the homeowners didn't want them. Sometimes homeowners don't want weep holes because they retract from the house's appeal – think smoothly rendered brick houses.
Weep hole drainage is essential for the healthy functioning of masonry wall systems in your home. Without it, water can accumulate within a cavity wall and create damage that can be both costly to repair and dangerous to the health of the home's inhabitants.