Blocked or Missing Weeps in Brick Veneer Walls

Masonry veneer wall drainage omission or blockage is risky

Brick Veneer Omitting Drainage - Barrier Wall Design

Not All Brick Veneers Lacking Drainage are Damaged - Some of these are Barrier Walls not Cavity / Rain Screen Walls

Above we illustrate a double-fault at a brick veneer wall weep hole found on a New York Home.

This "Do-it-yourself" excuse for veneer wall drainage is too small, placed above the level of the wall base flashing, and is completely clogged.

All of the weep holes we found in this wall were in the same condition.

Faux Bond Courses May Confuse the Identification of a Brick Veneer Wall - but is it a problem? Not Necessarily.

The brick walls of the New York home in our photo at below left contain no weep openings.

Bricks were laid tight against a solid masonry block wall with "faux" bond courses to the left of the chimney and all stretcher brick courses to the right of the chimney.

Walls both left and right of the chimney were constructed with no drainage.

Bricks were mortared against the masonry block structural walls of the home with no air space and no drainage provision.

This is a brick veneer on block structure approximately 30 years old. While the mason omitted weep openings, we did not find any evidence of water or frost damage to the brick veneer except at another wall where splash-up from roof spillage had worn mortar joints.

This is a barrier wall design, not a cavity / rain-screen wall designed structure.

That space allowed water that leaked into the wall to run down the wall interior and drain at the wall bottom - provided that the wall bottom included weep openings or drainage.

At BRICK FOUNDATIONS & WALLS we describe the collapse of the structural brick walled building shown at right.

Definition of wythe or brick wythe

1. Each continuous vertical section of masonry one unit in thickness
2. The thickness of masonry separating flues in a chimney - Masonry Design Manual

If you look at a brick masonry wall, one brick thickness of the wall is one wythe. A brick veneer wall constructed using full-dimension bricks will be one brick wythe in thickness (of the veneer). The total wall thickness will include the veneer wythe plus the thickness of the wall structure itself.

A structural brick wall is normally two or more wythes of brick in thickness, usually separated by an air space of about an inch to form a thicker, more dry wall. In the cross section of the collapsing brick structural wall at above right you can see multiple wythes of brick.

More brick and brick wall definitions and details are

at BRICK VENEER WALL LOOSE, BULGED.

Flashing Detail at Brick Veneer Wall Bottom

Carson Dunlop Associates sketch (below, with edits by us) illustrates the usual manner in which a brick veneer wall is supported.

At left in the drawing we see both the gap between the brick veneer and the building structural wall and wall bottom flashing that, if combined with weep openings, will permit water in the wall cavity to drain to the building exterior.

On occasion we find an "add-on" brick veneer supported by a steel lintel bolted to the building structural wall bottom.

Details about brick veneer wall support, bulge & damage, fasteners, and repairs for attached veneers on wood frame construction are found

at BRICK VENEER WALL LOOSE, BULGED.

Is it OK to Seal Weep Openings in a Brick Veneer Wall?

Leaks around windows in brick or stone buildings are common, particularly if the window flashing was not installed properly. On a masonry building with leaks around or above windows, some of our readers ask if they can stop the leaks simply by sealing up masonry weep openings found above the window.

The answer is no.

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.

Usually the weep openings themselves are not the cause of the leakage. Leaks at windows in masonry buildings often originate higher on the masonry wall. Water penetrates the wall at an open mortar joint or at other, higher wall penetrations, then runs down inside the wall cavity (particularly in structural brick walls or brick veneer walls).

Watch out: in these conditions, sealing the weep openings in the brick wall traps still more water inside the wall, increasing water and (in freezing climates) frost damage to the building.

So the proper repair is to find and fix the point of water entry.

OK to Install "wicks" instead of flashing and drain openings in veneer walls?

My daughter's house was finished in August 2013. It is located in Oklahoma. The bricklayer did not install flashing behind the weep holes.

To make matters worse, the weep holes are less than 6" from the soil. Some weeps are at ground level. Someone has suggested installing wicks to wick away any moisture. What is your opinion on wicks?

Do you have another suggestion other than removing portions of brick and installing the flashing?

Reply: some support for Wick veneer wall drains but Not our first choice: best to find and stop points of water entry

Wicks are used to try to drain water from a brick veneer wall are a recent alternative to flashing and weep openings in which a cotton, jute, sisal or even polypropylene rope is inserted up into the brick veneer wall at vertical mortar joints between bricks at a low course in the wall or over windows or doors where traditional weep openings would have been placed.

The wick material in widest use is a synthetic geotextile filter that is folded into molded channels inserted into vertical mortar joints in a brick veneer wall.

Research supporting the brick wick for veneer wall draining was by Yousuf et als in 2022 who researched the effectiveness of wicks instead of weep openings and who compared the effectiveness of different rope wick materials. I cite that article below:

• Yousuf, Haroon, Mazen J. Al-Kheetan, Mujib M. Rahman, Seyed Hamidreza Ghaffar, Nuhu Braimah, and Denis A. Chamberlain. Introducing a novel concept of wick drainage in masonry structures [Science Direct.com web page]  Journal of Building Engineering 51 (2022): 104332.
  
  Abstract:
  
  A new line of research is presented in this study where wick drainage technique was implemented in masonry walls.
  
  Three different types of wicks, two lignocellulosic natural materials, namely, sisal and jute, and one synthetic, polypropylene were installed on the external side of the walls with the aim of reducing dampness on their interior structure.
  
  Two masonry walls with cement and lime mortars were used, and a moisture-blocking material was applied to their surfaces.
  
  The physical properties of both walls were thoroughly investigated in terms of moisture content, seepage/retention of water and draining efficiency in the presence of wicks and results were compared with control. Results indicated the ability of wicks to reduce the water content inside the walls with higher efficiency for sisal, followed by jute and polypropylene, respectively.
  
  Sisal wicks increased the seepage rate of water to the exterior surface of masonry by 5%, followed by jute and polypropylene wicks with 4% and 3%, respectively.
  
  Moreover, sisal wicks remarkably drained over 70% of the supplied water after 14 days of testing.
  
  On the other hand, 58%, 53% and 10% of the delivered water was drained by jute wicks, polypropylene wicks and control, respectively. This could be explained by the chemical constituents and morphology of lignocellulosic materials, which are prone to absorb more water.
• BIA, BRICK VENEER / WOOD STUD WALLS TECHNICAL NOTE [PDF] (2012) Brick Industry Association, 12007 Sunrise Valley Drive Suite 430 Reston, VA 20191 USA - retrieved 2025/01/09, local copy saved as Brick-veneer-wood-stud-walls.pdf
  
  Excerpt:
  
  Weeps
  
  Weeps permit water to exit the wall and must be located in the mortar joints immediately above all flashing.
  
  Weeps must have a minimum diameter of 3⁄16 in. (4.8 mm) and may be spaced up to 33 in. (838 mm) o.c.
  
  However, larger, more closely spaced weeps provide better drainage and drying.
  
  Clear, open head joint weeps are preferred and should be spaced no more than 24 in. (610 mm) o.c. Noncorrosive metal, mesh or plastic screens can be installed in open head joint weeps if desired.
  
  Weeps formed with wick materials or with tubes should be spaced at a maximum of 16 in. (406 mm) o.c.
  
  Wicks used for drainage should extend horizontally along the length of the flashing and have one end extended up some distance above the anticipated level of mortar droppings.

Watch out: OPINION: While I certainly welcome research into brick veneer wall drain alternatives, this was a short term study that compared wick rope materials in brick wall drain systems. It contains no long term effectiveness data and lacks comparison with open or screened brick wall veneer opening effectiveness.

I'm worried that wicks won't allow sufficient drainage, that they will become clogged by masonry debris over the life of the building, and that where used low on the wall, the wick might even invite an insect attack risk.

It's also notable that none of these brick veneer wall drain "solutions" removed all of the water that penetrated the wall cavity. The best-performing drain removed about 70% of the water (in the short term and possibly much less in the long run), leaving water in the wall cavity, inviting frost and other building damage.

In my opinion, even without flashing, the best solution may be to install retrofit brick wall weep openings such as described in this article series.

Watch out: Other "Wicks or Prefabricated Vertical Drains (PVDs) or band drains" are used to improve drainage in soil around buildings. Don't confuse those drains in soil with brick veneer wall drains.

Beware of Building Additions that Block Veneer Wall Weep Openings

An InspectApedia reader asked:

I had wood flooring installed in a new home for a builder client of mine. The homeowners had a raised concrete patio installed and all the weep holes along the back of the house were covered by concrete after we installed the floor.

Several months later they called the builder and complained that the wood floor about 3 feet deep along the whole back of the house was buckling and heaving. I went to inspect it and attribute the problem to the covering of the weep holes thus preventing ventilation and moisture build up. Am I right?

Reply: Don't confuse "ventilation" and "water drainage" at brick veneer weep openings

"Ventilation" in the sense of a moving air current through the veneer wall, or loss of it, may not be the exactly-correct explanation of the buckling wood floor, though there can be little doubt, given the timing you describe, that adding the raised concrete patio and sealing off the veneer weep openings led to the floor buckling.

The purpose of weep openings is to let water out of the veneer wall rather than sending it into the building wall (and possibly floor) structure. That drainage is needed when wind-blown rain (or possibly significant amounts of condensate) in the cavity space between the veneer wall and the exterior sheathing of the wood framed wall behind needs to get out.

I see that more as water drainage than as air movement. Air movement might address or reduce condensation IF there were a lot of air movement but with just weep openings at spaced intervals along the bottom of a masonry veneer wall, there's not much air flow in that cavity space.

I would want a further on-site investigation to understand what happened. I suspect that actual water entered the wall cavity and the floor structure at the bottom of the wall.

If the floor is built on a slab then we can't see into that space without a borescope or some demolition, but I'd bet that if you did look into such a cavity for the case you describe, you'll see water stains (and maybe rot). Water and high moisture can indeed cause severe buckling of a wood floor, more so if the floor was installed without an expansion gap around the floor perimeter.

For the case you describe, I doubt that the floor buckled from normal expansion from normal moisture level variations - otherwise the buckling ought to have occurred when moisture levels changed (perhaps seasonally) even before the patio and outdoor raised slab installation were completed.

I suspect that water from rain penetrating the veneer wall, or perhaps even excess water from the add-on slab itself are what entered the wall and floor of the home.

Also see BRICK VENEER WALL LEAKS in FLOOD PRONE AREAS