Why don't old houses have weep vents?

Author: Prof. Clementine Torp MD  |  Last update: Thursday, January 8, 2026

“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.

Why doesn't my house 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.

Do old homes have weep holes?

Yes on all new or recently built homes. The code calls for this. On older homes there is seldom weeps and flashing but brick layers did a better job on older homes and if there is not an obvious moisture problem I do not call it.

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 don't have weep holes?

Without weep holes, water has only one place to go – inside your home's walls, leading to mold, rot, and unpleasant, expensive structural issues.

Fake weep holes retro fitted after the house has been built

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.

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.

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.

Can a house flood through weep holes?

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.

Can weep holes be added later?

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 all houses have weep vents?

“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.

Can water enter a house through weep holes?

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.

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.

What if my windows don't have weep holes?

The only windows that will not have weep holes are wood windows that use solid framing and are devoid of the chambers found in other window types.

Are weep vents required?

Are weep vents necessary? Weep vents are an important part of construction and they should be installed as outlined by local regulations. They help to provide the drainage and ventilation necessary for a healthy cavity wall.

What is the problem with weep holes?

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.

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.

How do you flood proof an existing house?

Close any foundation cracks with mortar and masonry caulk or hydraulic cement, which expands and fills gaps completely. Seal walls in your basements with waterproofing compounds to avoid seepage. Make sure any floor drains are clear of obstructions. Install flood vents.

Can you block up weep holes?

Furthermore, if you block your weep holes in an attempt to solve that problem then you will prevent the drainage of that water and the airflow needed to completely dry the cavity. This will likely cause catastrophic problems.

When were weep holes required?

Weep holes have been required by the Council of American Building Officials (CABO) building code since at least 1992, and they're recommended by the Brick Industry Association (BIA).

Do water pumps still have weep holes?

On a heavy duty water pump, you'll find a weep hole. Sometimes it will get clogged. Even though it may seem like a minor issue, it's actually something you have to address right away. Ignoring the problem will cause more serious problems down the road.

Do all drains have weep holes?

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

What happens if your house doesn't have weep holes?

If your building does not have flashing to protect against water, or weep holes to let it escape, its susceptible to water damage and possibly mold.

Does my house have weep holes?

Look for gaps in the mortar between the bricks: Weep holes are typically small gaps in the mortar between the bricks, located near the bottom of the external wall. These gaps are usually no wider than 3/16 of an inch and can be difficult to spot from a distance.

Do basements need weep holes?

As water leaks into the wall, it enters these hollow cavities and increases hydrostatic pressure. All this pressure can eventually cause water to leak into your basement and damage your foundation. While hydrostatic pressure can't be eliminated completely, it can be controlled thanks to weep holes.

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