Weep openings provide drainage in this brick wall (C) Daniel FriedmanBrick Weep Hole & Vent FAQs
Questions & answers about masonry veneer wall drains & vents

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Brick weep hole & vent questions & answers:

FAQs about the construction specifications & details for proper location, flashing, & protection of weep holes or drain openings & vents in brick or other masonry veneer walls.

This article series explains the purpose of drainage openings & rain screens in solid brick walls and in some brick veneer walls: brick wall weep holes and recommends their use in new construction and in some brick wall repairs or retrofits. Weep holes in building exterior masonry walls (brick or stone) are a drainage system that is used in cavity wall or rain-screen wall construction methods to get rid of water that has penetrated the outer wall skin or surface.

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Weep Holes in Brick Veneer & other Masonry Veneer Walls

Flemish bond brick wall, Vassar College (C) Daniel Friedman

These questions & answers about brick wall weep openings or "weep holes" that provide drainage for the brick structural wall or brick veneer wall were posted originally at BRICK WALL DRAINAGE WEEP HOLES - topic home.

On 2017-08-27 by (mod) - plug weep holes and move up one brick to prevent water from entering during rain & flooding?

Unfortunately there may be a problem that the flashing that directs water out of weep openings is at the bottom of most brick walls. So closing bottom openings and making higher ones invites a reservoir of water that enters and stays in the wall, making matters worse.

There is no meaningful air circulation through weep hole systems. That's not the point. Rather it's to let water drain out.

If I were unable to raise the home and had a problem of water entering weep holes at wall bottom during flooding I'd consult with a local engineer who has expert in retrofit for that situation. She might want to modify the wall to make it solid high-portland cement for a height well above high water.

In Venice people live with this flooding by also putting temporary barriers across the bottom of entry doors - and by moving living space higher in the building, and by using all masonry on the lowest level so as to reduce the amount of mold-friendly material to get soaked.

On 2017-08-26 by Andy

Can you plug weep holes and move up one brick to prevent water from entering during rain events do to improper drainage which can not be fixed. Will higher weep hole still allow circulation of air. I could always remove mortar if I ternal issue with water

On 2017-08-27 by (mod) - water draining from weep holes stains brick

Unfortunately the drainage of water from the brick vents is so important to avoid worse water damage to the building that you certainly would not address the staining by plugging up the vents.

I suspect that the stains are from contaminants picked up from inside the brick wall cavity as water penetrates behind the brick (perhaps a brick veneer) and runs down the wall.

It might be helpful if we knew what type of water barrier was placed behind the brick - do you have photos of the construction? Use the page bottom CONTACT link to send us more information if you can.

After having the brick wall cleaned of the stains you might reduce the stain pick-up on the brick by testing a clear masonry sealer, typically a silicone product. Test in a small unobtrusive area first to be sure the sealer itself doesn't stain the brickwork.

On 2017-08-15 by Peter

Our building is 6 years old. For the last few years white liquid has been coming out of the brick vent holes; which have plastic tubes in; and staining the brickwork.

On 2017-08-04 by (mod) - weep holes in brick veneer or weep holes in cabinets?


To have space and to permit illustrations I repeat your question and give a detailed answer in CABINETS & COUNTERTOPS

in a section titled Water damaged & moldy Kitchen or Bathroom Cabinets

Please take a look and let me know what further questions arise.


In correspondence we learned that Dinah meant that water leaking into the brick wall was, perhaps, causing damage to kitchen cabinets in the building interior. The attack on that problem requires a careful inspection of the brick exterior to find and repair water leaks into the structure. The fault is probalby not the brick weep openings themselves.

On 2017-08-04 by Dinah

I have a base cabinet that has mildew/mold in it, it is not near a water source. Could it be from blocked weeping holes? No other cabinets are affected and this base cabinet is not next to sink or d/w. Also, the mold/mildew appears to only be on the shelf and the wall of the cabinet that is not attached to the wall of the house.

It is perplexing as we can'f figure out why only certain places in the cabinet are moldy, other than when I searched outside I noticed the weeping holes had dirt in them. I can unblock the weep holes should I pour some bleach in them (only 2) and if so how much? My brick house is 4 years old built on a slab.
Thank you,

On 2017-03-25 by (mod) - retrofit of brick vents is indeed possible


It is indeed possible to drill or cut mortar joints and to add retro-fit weep openings if that's needed.

At BRICK WALL DRAIN, FLASHING, VENT SOURCES you'll find retrofit brick vent alternatives.

On 2017-03-25 by Velma

Have a brick veneer house built on slab in Florida in 1968. We have found no weep holes or vents. Is there another way it could be vented? We want to stain the brick but I don't want to cause the brick/mortar not to be able to dry out.

On 2017-02-27 by (mod) - contractor omitted flashing and brick vents, plans to drill holes later

Drilling weep openings after the wall has completed might improve matters but the risk is that cement falling into the wall cavity will fill in the wall bottom - blocking venting.

Pre-set weep openings work better as they'll be bigger and they'll usually include a shield. However at this point you've no choice but to retrofit. Nobody is going to tear down the wall.

I hope you see wall bottom flashing properly installed too.

On 2017-02-26 by Joe

I'm having a contractor put up new brick siding. He's already finished bricking about half way up the house. The house has 7/16 OSB sheathing and the black tar paper. I asked him where are the weep holes and he said he would drill them after the job is done.

We had a long discussion about that not being proper practice, but I can't ask to take down all the installed brick at this point. Will this be a major issue with water/moisture getting into my house in the future? Will drilling holes after the job is done work ... or help the problem? I live in the north-east (NJ).

On 2017-02-27 by (mod) - Do exterior cavity brick walls require weep holes

Yes, Vicki. Wind-blown rain will enter even the best brick exterior and needs a way to get out if damage is to be avoided.

On 2016-12-19 by Vicki

Do exterior cavity brick walls require weep holes

On 2017-02-27 by (mod) - weep holes be put in the brickwork around a curved arched window?

Liz, I can't of course give a certain answer as I don't know the details of your building nor the window, but on a 1-3 story residential building the brick vents or weep holes are put at the bottom of the wall, not around windows.

I agree that there could be a need for drainage above a window in a brick cavity wall or veneer wall, though it's not something I've seen. More-likely we rely on flashing above the window.

On 2016-09-05 by Liz

Where should weep holes be put in the brickwork around a curved arched window? There are none around our window.

On 2016-06-21 by (mod) - mininimum distance a concrete path can be from the bottom of the weep hole

Interesting question. I've not seen a ground-cleareance specification for brick veneer weep holes. But you're quite right that water entering such openings from the ground could cause building damage. Schneider's question and answer in the article above discusses Texas flood water entry into structures through wall weep openings.

A subtle component of just what that damage risk is depends on how the veneer wall is constructed, the height above grade of the bottom masonry lip or steel rail on which the veneer wall sits, and the in-wall height of the in-wall flashing at wall bottom that directs any in-wall-cavity water out through he weep holes.

My OPINION is that the weep hole should be high enough that it won't pick up surface water runoff during rain or periods of melting snow; that may vary by individual situation from an inch upwards.

On 2016-06-21 by Shayne

What is the min distance a concrete path can be from the bottom of the weep hole

Question: Leaks & mold growth in brick veneer walls that admit water during flooding

(Mar 13, 2012) WEill said:

if water enters the weep holes during a spell of high water, and allows some water into the building. if the sheet rock is not wet, will mold still grow inside the wall? if so how should i dry it out?

(Feb 18, 2013) Levertis Steele said:

Water rises above the weep holes when it rains in my backyard for several hours. Water seeps in from somewhere and covers most of the room it enters. After the rain stops and the water level outside recedes, the water drains from the room in the same direction from where it came. I thought that it was coming through the weep holes. What is wrong?

Reply: lower the water or raise the house


Even with a lot of experience with mold detection and remediation in buildings I can't say for certain that mold will or won't grow at a specific location on a house I've never seen. But certanly drywall is very mold friendly. If drywall is wet or even if it's not, if there is water inside a wall cavity that sends moisture higher in the wall cavity to where drywall is located, you can expect problematic mold growth to show up.

You can explore the suspect area for visible mold by making a test cut into the most-suspect location. Check the cavity side of the drywall for visible mold and also check nearby wood framing and insulation.


Periodic area flooding that is submerging a building wall to heights above the top of the foundation wall suggests some more serious steps are needed to control floodwaters, or if that's not going to be reasonable or reliable, to live with water entering the property, structural design changes are needed.

In an area of very limited water and rot problems on a flat site in New York, I addressed a water entry and related rot/insect damage problem by chopping off the bottom two feet of a wood frame wall and buiding up the wall base with a couple of courses of solid concrete block.

Question: ok to cover up weep openings ?

(Sept 11, 2012) Anonymous said:

I have weep holes located on the 2nd floor of my house. above and below a window and also a few towards the base of the 2nd floor. Can these be covered up?

Reply: no, probably not

Closing off weep openings in a masonry wall, presuming that they were properly located, installed, and flashed in the first place, risks trapping wind-blown rain or other water inside the wall cavity, inviting structural damage, rot, or mold contamination.

Question: Masonry wall weep holes vs Wind-blown rain water entry

(Sept 22, 2012) dena said:

we have water after a blowing rain coming over the brick ledge which sits on the basement foundation .the water did not drain out due to the builder installing the flashing wrong it is on the outside of the tyvak.the moisture caused the vapor barrier to condense and now we have a mold problem. can we remove several couses of brick to repair the flashing?

a builder wants to remove all the brick around the house which is very expensive and money we don't have as we are senior citizens and in bad health.

a masonary man says he can remove several courses by leaving some of the bricks every 5 feet.can this be done?


I think your mason may have more experience with brick veneer than the builder, and his suggestion is worth a try. But be careful. 5 feet as the drainage opening interval may be too big a gap.

An unknown is the number and spacing of ties to the wall structure. If the wall is not supported enough and thus cracks you'll end up removing it all. Try working on just one segment at a time and perhaps leave more bricks loose but in place, removing the temporary support ones just briefly during repair and re- flashing. Send me some photos and perhaps we can comment further.

Question: how to un-block clogged masonry wall weep holes

(Feb 17, 2014) Sal said:

I have round weep holes along my brick retaining wall that are not working. Is there anything I can use to unclog them?


Sal, possibly - it depends on the problem. If the weep holes are clogged from insects, such as mud dauber wasps who love those openings, a careful routing with a suitably-sized tool and maybe using a shop vac to draw out as much debris as possible may be enough.

For a retaining wall (as opposed to a brick veneer or structural brick wall) it's also most likely fine to try jamming a rod back into the soil behind the wall, through the weep opening.

But if the weep holes never worked because they are blocked by dense mud, lacked gravel backfill, are clogged by concrete, or some other snafu, you'd need to take a different approach, possibly involving a long masonry bit. Perhaps if you use the CONTACT link to send me some photos I can comment further.

Question: flashing snafus mean leaks blamed on weep holes

4-17-2014 Ted said:

I have weep holes above my windows and door. The rear of the house is exposed to blowing wind and rain. I have leaks in three windows, one easily seen dripping from the top window frame the others I suspect are running down around the edge of the window and coming out below the window from the lower trim, running down the inside walls.

I had the windows caulked and as an add on the contractor, as a favor, added metal wrap to the lentil and caulked around that too. First really heavy wind and rain storm came and now the leaks seem worse. I suspect the flashing must have been run out through the lentil and that wrap and caulk job are the reason it's worse.

Am I correct in that thought? Should I take the wrap off of the lentils? How should I check for proper flashing as I had leaks before the wrap and caulk job?


Ted, I agree that it sounds as if the flashing above windows and doors was omitted or not properly installed or punched or damaged during construction. I can't see how to fix this easily without some exploring into the wall cavity to see what's going on. Check out Carson Dunlop Associates' page top sketch (click to enlarge any image) to see what the flashing position should be.

Keep in mind that even if the flashing is properly installed, if a lot of water is leaking into the wall from higher-up, the water might be running down the wall sheathing and behind the flashing and out from underneath it. That diagnosis is what's needed before we try to fix anything.

Watch out: Certainly we don't want to just close off weep openings or caulk in the wrong place or we risk either water accumulation in the wall or severe rust and lintel damage.

Question: do weep hole vents extend from foundation to roof line?

4/18/2014 Rodney Thompson said:

Have you ever heard of a weep hole extending in a straight verticle line from the foundation to the roof?



A weep opening in a brick veneer wall is placed at intervals and at one or more location heights always including the wall bottom and possibly at higher points in the wall depending on how the wall is constructed.

The open space behind a brick veneer wall is typically intermittently partially obstructed by extrusions of mortar in the veneer, depending on how the wall was built, but hopefully nowhere is the air space totally obstructed across the whole width of the wall - so moisture can find its way to a weep opening for exit.

SO yes the air space behind a veneer wall extends, though irregularly, from wall base to wall top. But no, not explicitly in a "straight line".

The "wall top" may not extend to the roof line - that depends on how the building is designed and how high the veneer wall extends.

Question: dirt coming out of retaining wall drain openings

(June 1, 2014) Kathryn Mundy said:

dirt is coming out of retaining wall weep holes in patio. I have tiny patio that abuts earth -- the top of the wall is at ground level of a row of neighbors that live up a hill behind me. I had this home 15 years. In last month I now have large piles of Dirt at openings of the 3 weep holes (I have photos) .

We recently had 3 days torrential rain; also possible there are mice (I live very near a river in a small town and river redraws rats and mice) also last year neighbor behind me built picket fence at top of wall (the earth behind wall is a dirt path with landscaping that leads out to parking area. What would suddenly be forcing so much dirt to come out of the weep holes at bottom of my retaining wall?



It's common for soil to wash through drain holes in a retaining wall, especially after heavy rains. If the wall has not moved, bulged, cracked, then it sounds as if the drainage openings are doing their job.

I'm not sure why there would be a sudden change, perhaps settlement or a surge in water behind the wall.

To avoid confusing other readers, a retaining wall is NOT part of a building structure, it is a wall built to hold back earth.


Question: when to close off weep or drain openings in walls

(June 4, 2014) Virginia P. said:

I am converting my front porch into a room. The contractors says we can leave the existing brick walls with the weeping holes in place. He wants to keep the wall, and built over it.

Some people tell me we should have the brick wall removed so moisture will not built up and create mold. The contractors says its not necessary. I don't know what is correct. What should I do?



I don't understand how your existing porch is constructed nor where the weep holes are located in it. If you are describing drain openings in a masonry wall that is earth filled, over which a porch slab was poured, leaving them in place is harmless. In any event the intent of drain or weep openings is to allow rain or other water penetration to exit the structure.

Sealing them, in general, risks future trapped water and a moisture problem or in freezing climates, frost damage.

Question: increasing the length of brick wall weep tubes: owner pouring water behind brick to test for leaks

(July 22, 2014) Anonymous said:

Stucco Tec / I am a brick mason we are laying 60000 brick and using weep tube the home owner has been running water behind are brick to see if the weep tub is working 80% of them are working the others are plugged with mortar that has fallen behind the brick which will happen I am now going to make my tubes longer what do you think is a good idea. Thank You Stucco Tec



I think the owner is not doing a very good thing to pour water in volumes far greater and at a greater rate than the brick veneer wall design would anticipate - a result risks leaks into the wall cavities, floors below, mold, insulation damage.

It is common for some weep hole openings to become clogged with fallen mortar. If it's just a very few and if weep openings are frequent enough along the wall bottom, it's not likely to be a concern. More important is proper flashing at the wall base to be sure that water is directed out to the weep openings.

However if you detect a clogged weep opening before the mortar is hard-set you might be able to just clear the existing opening or cut it bigger and insert one of the retrofit weep opening products in this article.

Longer tubes at weep openings may still become mortar clogged and certainly you don't want the end of the tube to be jammed up against the sheathing of the exterior wall.

What do you think about using some of the other weep opening products shown in the article above. There are products for both original installation and for retrofit.

Question: how to stop interior wall rot *& plaster damage behind brick walls in Salt Lake City

(Sept 1, 2014) Susanora said:
What can I do to stop the wall rot (interior crumbling plaster & also some crumbling of interior ferrocement) behind my 1938 brick - lath walls?

The brick frame house has no weep holes, and the problem is only on the west side along about a 15 feet section, all above grade. I think condensation may be part of the issue - this is in Salt Lake City and driving rains are not frequent.

I have had the house for 24 years and the problem has been continuous - I repaired the interior plaster several times, then gave up & hung cloth over the mess. No mildew or mold, but it is a significant cosmetic problem. Is there any way I can add ventilation from the inside of the house to the airspace behind the brick? It is so arid here (average humidity 15% - 20%) wouldn't it be possible to ventilate the cavity from inside of the wall?


Rot, which refers to organic materials like wood, is caused by a combination of water and wood destroying fungi, often basidiomycetes, sometimes more serious Meruliporia.

The right epair is to stop the source of water entry and to determine if structural repairs are needed.

I'd also look for insect damage in the same areas.

If you think condensation is occurring in the wall from indoor humidity I'd look for and fix any sources of indoor moisture and I'd seal penetrations into the wall such as around receptacles.

I would not try venting the wall cavity to the indoors - you may invite IAQ problems.

I would look at some of the brick veneer drain retrofit products we describe in this article.

Question: why need flashing as well as brick wall weep or drain openings?

(Sept 6, 2014) JJ said:
Why is there both weeping holes AND flashing? Can't water get out through flashing alone? I am not understanding the logic: do they both perform the same function? Thanks!


No the flashing would be sealed by the mortar course.

The weep holes are the water exit; the flashing is the water director.

Question: ok to omit masonry wall drainage openings in short sections?

7 January 2015 Anonymous said:
I have a long brick exterior wall. Near the end of the wall is a double door and then just a few more lengths of brick prior to the termination of the wall into hardi-plank. Is it needed to install a weep hole in the brick in this short length. There isn't one currently.

I feel there is plenty of weep holes on this wall on the other side of the door to allow for air pressure equalization, but I don't see how moisture could escape between the door and the end of the wall (moisture can't go up and over the door opening to the other side to travel out of those weep holes).



The weep holes' job is less air pressure equalization and more water drainage.

Obviously we don' t need continuous weep openings at the bottom of a masonry wall, the openings are spaced at intervals. However an individual wall section bordered by other structural elements, that is not connected to drained wall sections, should have its own weep openings even if only one is fitted.

Having a weep hole in even that short wall section would reduce the chances of water accumulation therein and thus related building damage.

You can make a further risk or needs assessment if you can inspect the building interior walls below the section you are talking about - e.g. from a basement or crawl space where you'd look for leak signs, and you can also assess risk by noting conditions outside that increase the risk of leaks into that section of wall cavity such as an un-flashed or leaky window, door, or cracks in the brickwork.

Question: Effloresence on brick traced to weep holes under windows

(Mar 29, 2016) Harold said:

My son is under contract for a tow home in the Washington, D.C. Area. It is a 3 story brick facade structure built about 2012.

We had the home inspection and the inspector pointed out that there is a lot of efflorescence from weep holes under the 3rd and 2nd floor windows, seems to be weeping from many weep holes, not just under the windows but across that width of the building in those 2 rows.

This is a large community but our observations are that this efflorescence from the weep holes seems only in this home and the home attached to it.

Is there reason for concern? Any guidance and information about why this should or should. It happen is greatly appreciated!
Thank you in advance for your time and kind consideration.

ps: if there is a way I could add a picture, il be happy to.


Harold: you can send photos using the page bottom CONTACT link to send me images by email.

Effloresence is indeed an indicator of water or high moisture. Any unusual moisture sign is worth investigating. The questions are

1. where is water coming from
2. where is it going
3. what damage has it done or might it do (rot, insect damage, mold contamination, frost damage)


Question: is repair needed if you buy an old home with brick siding and no weep holes?

(May 6, 2016) Gary W. said:
It its always advisable, when you find a older house without brick siding weep holes, to recommend professional masonry repair. Or, suggest repair as an upgrade?

Reply: maybe

Good question, Gary.

If every bad thing that could happen because of every bad construction detail always in fact happened, more of us would be smarter and we'd make those mistakes less often.

So on an older home with a brick veneer that lacks weep holes, before getting too scared I'd investigate the wall construction to be sure that it is not solid masonry or is not built in a design for which weep openings are not appropriate.

Once you've confirmed that the wall is indeed a brick veneer behind which is an air space - thus a rain-screen design - then there is more investigating to do:

1. First I would inspect for damage with care, especially at the sills in the basement or crawl area. If I found damage there I'd be sure the client saw it too, and we'd need to figure out (perhaps with help) what repair was needed. In that case, the missing weep holes can have caused the damage and so their addition might be needed as a retrofit as part of the repair.

2. Second, if there were no signs of damage I'd look for signs of water entry. If there were no signs of water entry and no signs of damage, then the mistake may not be hurting this particular home. Of course there can be hidden leak problems higher on the wall that haven't shown up, but as water runs "down" we look in the highest-risk locations first and most aggressively.

3. Third, I'd be careful, in the - no damage found - case, about recommending retrofit weep holes since improperly added on a home where there is so far not damage, we might be causing more harm than good.

I do not like home inspection report language that uses the "upgrade" term. In my opinion the inspector is ducking and weaving to try to play it "safe" - having disclosed a defect, while appeasing the real estate community who worry about the scare-effect of disclosing "defects" on a home. Be careful using that term. For example, repairing aluminum wiring is not an upgrade, it's correcting a serious fire safety hazard.

A home inspector has enough to do finding costly repairs that are needed and unsafe conditions that need to be corrected. Calling repairs "improvements" risks causing confusion and raises the spectre of conflicts of interest.

Question: minimum ground clearance distance for brick weeps

Shayne said:
What is the min distance a concrete path can be from the bottom of the weep hole


Good question; we have published a detailed reply to this worry at BRICK VENEER WALL WEEP HOLE LOCATION


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