Masonry Weep Holes

This is Why Brick Walls Have Weep Holes

In Technical Details by Giovanni ValleLeave a Comment

If you’ve ever wandered by a brick home or building and wondered what unlucky builder forgot to fill some holes in the wall, you’re certainly not the first! However, those tiny holes, called weep holes, were intentionally placed and serve a very important purpose. If you’re interested in purchasing a modern brick home, it’s imperative to understand why brick walls should be equipped with weep holes and how they will help keep your home safe and secure.

Brick walls must have weep holes to allow water that is absorbed by the brick to exit the wall. If water gets into the wall and has no way to exit, it will penetrate further into the wall and create long-term structural damage.

Weep holes in brick walls serve a much wider variety of purposes than just keeping water out of your home. Outlined below is all of the information you will need to understand exactly why brick walls need weep holes and all of the ways they contribute to the structural integrity of your home.

Does Brick Veneer Need Weep Holes?

Brick veneer walls must have weep holes to prevent water from penetrating through the brick outer layer and causing water damage to the actual framing of a home. Once water makes contact with the framing materials, it can cause short and long-term water damage that will severely impact the stability and longevity of the house’s structure.

Do All Types of Brick Buildings Have Weep Holes?

Before the mid-1900s, most brick buildings were built with solid brick masonry, meaning that they were constructed solely with multiple layers of brick. Nowadays, modern brick homes are built with brick veneer masonry. In this building technique, the house’s interior structure is a wood or concrete wall that is covered with a single layer of brick on the outside to create the aesthetic of an older-style brick home.

In solid brick structures of the past, an inner layer of soft brick trapped and absorbed water that crossed the outer threshold, which would then vaporize back into the air. Because brick veneer structures have only one layer of brick, any water that passes through that layer will be absorbed into the wall behind it. Because wood and concrete do not absorb and release water the way bricks do, this can lead to serious water damage if the water can’t exit the wall.

The majority of the brick homes that have been constructed in the last half-century are built using the brick veneer method, so unless you’re purchasing a very old home, your house was likely built using this technique and should have weep holes.

What Exactly Are Weep Holes?

Weep holes are small, uniformly-spaced openings between bricks where the mortar would traditionally be. These openings are intentionally left by masons to allow water that is absorbed by the brick to drain water and prevent it from seeping into a house’s structure. Generally, they will be found along the bottom of a brick wall right above the foundation but can also be found over doors and windows.

How Does Water Get Inside Brick Walls?

Most people think that rainfall is the only culprit to water penetrating brick walls, but there are many other ways that water can seep its way into brick structures. Moisture can be accumulated in brick veneer walls in the following ways:

  • Rainfall
  • Moisture from Humidity
  • Snow
  • Freeze/Thaw Cycles


Hard, driving rains can have an immediate impact on a home with improperly built walls in the form of flooding. This can particularly be a problem in areas with rainy seasons or in hurricane or tornado zones.

Moisture from Humidity

Though this type of moisture is not visible to the eye like rain, it is just as detrimental to a home. Moisture built up from humidity that can’t be drained will ultimately find its way into the structural walls in the form of rot or mildew.


Even though it may look light and fluffy, snow carries plenty of moisture that can seep through brick walls just like rain. This can particularly be a problem after a heavy snowfall that covers a home’s foundation. If the snow sits around for too long, moisture can begin to seep into the home.

Freeze/Thaw Cycles

Freeze/thaw cycles often get overlooked in terms of how much moisture they produce, but they can be a major problem for brick veneer homes. Piled up snow on windowsills and around a home’s foundation adds up to quite a bit of water once it melts. Melted snow or ice dripping from trees or roofs can also cause additional water buildup. 

Without proper protection, homes can be subject to significant moisture accumulation during every season of the year. Intangible water sources, such as the buildup of moisture from humidity, can be particularly damaging over time if not addressed. It’s important to be aware of which type of climate you live in and which of these natural phenomena will be most likely to bring additional moisture into your home.

What Happens When Moisture Enters a Brick Veneer Wall?

Because the veneer wall is generally a very thin layer of brick, it doesn’t take much for moisture to make its way through and begin its dirty work on the structural masonry. Once the water has penetrated the veneer, it can cause damage to the interior structure of the home through:

  • Leakage
  • Rot
  • Mold/Mildew
  • Insulation Problems
  • Ventilation Problems

Leakage Can Cause Damage

The most obvious way to spot moisture damage is through water leakage into the home. Leakage can manifest as a slow, constant seeping of water to an all-out flood from a period of extremely heavy rainfall. Without properly installed weep holes in veneer to let the water drain away from the building, it will have nowhere to go but right through the wall.

Rot Causes Structural Deterioration

Wall rot is particularly an issue in brick veneer homes with wooden structural walls. Once water penetrates the veneer wall, it begins soaking into the wood siding, which can cause massive structural deterioration and damage. Wood rot is particularly important to avoid because it’s difficult to spot when it’s occurring.

Mold/Mildew Endangers Health 

The nice warm space between the brick veneer and the structural wall becomes the perfect breeding ground for mold and mildew once water makes its way in. If not treated, mold and mildew will not only decrease the structural integrity of a home, but it can leave a noxious smell and potentially cause health problems for a building’s occupants

Insulation Problems Can Increase Energy Bills 

As a general rule of thumb, moisture in a wall reduces its insulation capacity. Therefore, heating and cooling systems have to work harder to properly insulate the building, resulting in increased energy bills.

Poor Ventilation Causes Problems 

Believe it or not, those tiny weep holes go a long way in helping improve a home’s ventilation. Weep holes allow air to move freely around the internal wall cavity and prevent rot and mildew from building up on the structural wall. Without proper ventilation, the structural wall may be subject to deterioration or damage.

Ultimately, moisture entering through brick veneer that isn’t properly outfitted with weep holes can cause significant structural and financial damage to a home or building and can potentially even impact people’s health who live or work inside. Properly placed weep holes in a brick veneer wall will significantly decrease the chances of these issues occurring and increase the safety and longevity of a home.

Where Should Weep Holes be in Brick Veneer Walls?

Due to the unique construction of brick veneer walls, there are very specific locations that weep holes need to be placed to prevent a buildup of water between the structural building layer and the outer veneer. 

It is important to ensure that weep holes are correctly placed and supported before purchasing a brick veneer home. Listed below is more detailed information on where weep holes should be placed.

  • Should Weep Holes be Placed Along the Foundation?
  • What Does Flashing Have to do With Weep Holes?
  • Do Brick Walls Need Weep Holes Above Doors and Windows?

Should Weep Holes be Placed Along the Foundation?

The most important place for weep holes to be placed in brick veneer buildings is in the very first layer of bricks placed on top of the foundation. Usually, these weep holes will be vertical voids replacing the mortar joint and should be placed 24” to 36” apart horizontally along the wall. It’s important to make sure that the weep holes do not penetrate any flashing that is placed between the veneer and the interior wall.

What Does Flashing Have to do With Weep Holes?

Flashing is an important part of brick veneer masonry and plays an integral role in ensuring that water does not penetrate deeper into the wall. Flashing is a very thin layer of synthetic material that is placed between the brick veneer and the foundation wall. It extends about 6” up the foundation wall, and out 6” into the foundation. Flashing can be made of:

  • Synthetic Rubber Membrane
  • Copper
  • Stainless Steel

Essentially, the flashing acts as a gutter to effectively funnel the water released by the weep holes and divert it away from the structure. This is why it is so important that the weep holes are placed above the flashing but do not penetrate it. If the flashing is cracked or punctured, the funneling mechanism will not work properly. 

Does Brick Veneer Need Weep Holes Above Doors and Windows?

The requirement for weep holes above doors and windows is dependent on an area’s building code. As a general rule of thumb, weep holes should be placed anywhere that there is flashing and should be placed below doors and windows to divert moisture away. If you’re unsure whether or not a structure is required to have door and window weep holes, check the most recent building codes for your city or area.

At the very least, brick veneer buildings need weep holes regularly placed across the foundation in conjunction with properly installed flashing. If weep holes are clogged or not present to divert moisture away from the structural walls and the foundation, both will inevitably sustain long-term water damage that may not be able to be rectified.

How Are Weep Holes Made?

Over the years, masons and builders have developed a variety of different techniques to install weep holes in a home. The weep holes may look very different depending on the technique used to install them. Below is a list of the different styles of weep holes and what they look like on a brick wall.

  • Open Head Joint Weep Holes
  • Cotton Rope Wicking Weep Holes
  • Tube Weep Holes
  • Oiled Rope or Rod Weep Holes

Open Head Joint Weep Holes

Open Head Joints are the most common types of weep holes seen in brick veneer. They are created by removing the mortar from the vertical joint between two bricks. They are generally the same size as typical joint spacing with mortar, so they are the most visible type of weep hole. These weep holes also generally include a drip on the front lip to help with water drainage.

Cotton Rope Wicking Weep Holes

This process uses a cotton rope up to 12” in length that is placed in a vertical joint and extended into the cavity wall behind the brick. The cotton rope absorbs any water that comes through the veneer, which is then wicked back to the outside. Rope wicking holes are smaller than open head joint weep holes and take longer to release absorbed water back into the air. 

Tube Weep Holes

Weep holes can also be created from hollow tubes made of plastic or metal. They must be placed at exactly the right angle. If the angle is too steep, the water that’s draining out of the wall might be re-absorbed further down. If it’s too flat, the water will get caught in the tube and fall back in towards the structural walls.

Oiled Rope or Rod Weep Holes

This technique uses an oiled cotton rope or rod that is physically mortared into the brick joints. The oil prevents the mortar from bonding around the rope or rod, and it is pulled out of the joint once the wall has set. These holes are slightly less conspicuous than tube weep holes, so they’re often used to achieve a more uniform aesthetic in the brick wall.

My House Doesn’t Have Weep Holes. Can I Get Them Installed?

It is possible to get weep holes installed in a home that doesn’t have one, but it is not easy and very time-consuming. Additionally, there most likely hasn’t been any flashing installed if there are no weep holes, which adds another step to the process. Adding weep holes post-construction usually involves entirely removing brick sections 3-4 feet at a time, installing flashing and weep holes, and re-installing the bricks. If you need weep holes installed, contact a professional builder or mason for assistance.

Is it Okay to Cover Weep Holes?

Weep holes should never be completely clogged or covered up, as this will prevent moisture from draining out of the wall. However, there are ways to partially cover weep holes to protect them from intruding pests while still allowing water to effectively flow out of them.

One of the biggest complaints from homeowners is that insects and rodents can enter into the home and get into the walls through the weep holes. Fortunately, this situation can easily be prevented by using the following products to safely protect weep holes:

  • Stainless Steel Cover
  • Stainless Steel Wire Mesh
  • Copper Wire Mesh
  • Stainless Steel Wool

Stainless Steel Cover

One of the most effective ways to keep pests out of weep holes is by inserting a stainless-steel cover into the hole. The covers are strong enough that mice can’t chew through them and leave just enough space for water to freely pass through. The steel is flexible and can fit into different sizes of weep holes with minimal finagling.

Stainless Steel Wire Mesh

Stainless steel wire mesh can be laid over the top of a weep hole to block rodents and insects from entering. The mesh is strong enough to withstand chewing and won’t rust or corrode when exposed to water flowing through the weep hole. 

Copper Wire Mesh

Because of its flexibility, copper wire mesh is a bit easier to cut and shape than stainless steel and won’t fall prey to chewing mice. However, copper doesn’t weather well over time, and the wire can oxidize.

Stainless Steel Wool

Stainless steel wool is sometimes recommended to cover weep holes, but the drawbacks of this material tend to outweigh the benefits. While it is strong and obstructs clearance for even the smallest insects, it can obstruct airflow and impact a home’s ventilation. Stainless steel wool also rusts very quickly, so it needs to be changed out multiple times a year.

While it may be tempting to completely cover weep holes to keep insects and rodents out of the home, the long-term damage that will be done by completely plugging them is not worth it. Fortunately, these solutions are easy to install and effective at keeping pests at bay while allowing weep holes to protect the home from long and short-term perils of water damage.

Share this Post

Leave a Comment