Do I need weep holes?

Author: Jordy Kub  |  Last update: Monday, February 10, 2025

You should have weep holes in your waterproofing system if your foundation is made of concrete masonry units, also known as CMU blocks, cinder blocks, or concrete blocks. As a result of all this pressure, your foundation may eventually become damaged by water seeping into your basement.

Are weep holes really necessary?

Without masonry weep holes, or if the existing drainage system is blocked or broken, capillary action can result in the water becoming trapped inside the cavity wall.

What happens if you don't have weep holes?

Ventilation of the internal wall cavity - Without ventilation, mildew, dry rot and damp reduce the life of the internal wall studs and other building materials within the cavity. Inadequate ventilation is the main cause of "Leaky Building Syndrome".

Are weep holes mandatory?

Yes, Australian building codes mandate weep holes in masonry to ensure proper drainage and ventilation, safeguarding structural integrity and preventing moisture-related issues in buildings.

Are weep holes required by code?

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.

What Is A Weep Hole And What Do They Do?

What is the alternative to a weep hole?

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.

When did weep holes become code?

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.

What happens if you block weep holes?

Blocking your window weep holes predisposes the window structure to water damage, rust, and corrosion ultimately reducing your window's lifespan.

Why does my house not have weep holes?

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.

Where are weep holes required?

Therefore, weep holes are at the bottom of brick veneer, just above the top of the foundation, and directly above the termination point of any flashing installed behind the brick. Weep holes also should be located above doors, above and below windows, and above any other openings in the brick wall.

Can I drill my own weep holes?

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.

Are weep holes essential?

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.

Do all drains have weep holes?

Functionality: Whether tile insert drains contain weep holes depends on the specific design and intended use.

Should all windows have weep holes?

No, many windows don't have weep holes. They're not usually found in wooden window structures. But you can expect to find weep holes in many vinyl windows and aluminum models and any window type that slides or rests in an outer frame that has a bottom track.

Do cavity walls need weep holes?

Weepholes to cavity walls should be provided:

to cavity trays above openings and penetrations through the wall (such as sub-floor vents, ducts or flues), at least two per opening at not more than 450mm centres. at least one to the bottom tray in a series of stepped cavity trays, eg at pitched roof abutments.

Do weep holes let cold air in?

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.

Do you have to have weep holes?

Where flashings are incorporated in the masonry, weepholes shall be provided in the masonry course immediately above the flashing, at centres not exceeding 1200 mm. Meaning that weeps holes are required in more places than just around the ground floor slab of a house.

How important are weep holes?

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.

What can I use to fill weep holes?

While you should never fill weep holes with solid material—such as caulk, wood, or mortar—you can put strips of fiberglass screen wire or a scouring pad in the weep holes to keep insects out.

Is it OK to cover weep holes?

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.

Do cinder block walls need weep holes?

After the blocks become filled with water they leak into the basement. The basement waterproofing weep holes drain the water from the blocks below the floor level. Only by drilling into every single core of every single block does it become possible to drain the entire wall.

How often do you need weep holes?

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.”

Do I need weep vents?

Weep vents are usually required where there is a cavity between two walls such as in brick veneer or double brick constructions. They are typically installed at the base of the wall above the flashing. Building codes or regulations will state their spacing and required locations.

What happens when weep holes are blocked?

Water Stains or Discoloration: Noticeable stains or discoloration on the exterior walls, particularly around the weep hole area, may indicate water pooling behind the cladding. Mildew or Mold Growth: Excessive moisture due to blocked weep holes can create an ideal environment for mildew or mold to thrive.

What are the requirements for a weep hole?

Weep holes shall be provided in the exterior wythe of masonry walls and shall be at a maximum spacing of 33 inches (838 mm) on center (o.c.). Weep holes shall not be less than 3/16 inch (4.8 mm) in diameter.

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