weep holes

Old 11-25-02, 09:50 AM
John Duggan
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weep holes

My house was built 1 year ago and does not have weep holes in the brickwork. When I asked the builder about it, he said that the house wrap used negates the need for them. He also said that the mortar that squeezes out of the back during construction plugs up the weep holes anyway. I am not sure I believe him, but even so, is there any solution at this point?
John Duggan
Old 11-25-02, 09:50 PM
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Weep holes in brick veneer

Brick Veneer Homes (Home)

John P. Bridge

I often hear people in the Houston area talking about "brick" houses, when in fact, during my nearly twenty years in the area, I have not seen even one brick home. There may be one or two of them around, but I haven't seen them.

And it's a good thing there aren't more of them, because they simply aren't all that great. I once owned a solid brick home in Phoenix -- solid (bonded) brick all the way through with plaster applied to the inside walls. The brick began to slowly heat up in the spring and didn't cool off until winter, which in Phoenix is not that cool. The house had one advantage: Termites could not eat its exterior walls.

In any case, we don't generally have brick homes in Southeast Texas. What there are instead --and there are plenty of them -- are brick veneer homes. Brick veneer is not structural; it doesn't support anything, including the roof. Brick veneer is, in fact, mostly cosmetic. What supports the roof structure is the wood frame wall that lives behind the brick veneer.

There are several advantages to brick veneer over bonded (solid) brick. First of all, the walls can be properly insulated. This is impossible with solid brick. Next, since there is only one thickness of brick (the veneer) on the outside of the house, the structure is lighter than one built of solid brick. Finally, given the propensity for things to shift and crack around our neck of the woods, brick veneer is easier to repair than its solid counterpart.

Brick veneer is, then, a very good system for exterior walls. It gives a home the appearance of having been built solid, yet it maintains the advantages of wood or metal framing. It is a very good system indeed . . . if it is done correctly. And here we go again.

Weep Holes, Air Circulation and Water Repellency

In a brick veneer installation, the very first course of bricks is laid upon the portion of the foundation or "beam" that is referred to as the "brick shelf" or "brick ledge." When inspecting a brick veneer home you will notice that this first course contains gaps every several bricks where the vertical mortar joint has been omitted. These gaps or omissions are called "weep holes."

Weep holes allow the space between the brick and frame walls to breathe. The holes also (ostensibly at least) allow any water that accumulates behind the bricks to escape. I'll tell you right now, though, if there is water accumulating behind your bricks, you're in trouble. Something is wrong.

Here is the usual problem with weep holes. Are you ready? They are almost always clogged with mortar which is dropped by the bricklayers as the wall is laid up. Let's look a little closer at how a brick veneer wall is arranged.

First off, carpenters frame the house, and then they apply some sort of sheathing to the exterior portions which will be veneered with bricks. The sheathing might be asphalt-impregnated fiber board or a paper product that incorporates a radiant barrier. Sheathing can also be made of other substances, including Styrofoam and exterior sheetrock (gyp-board).

When the bricklayers do their thing, they leave about a one inch space between the sheathing and the back side of the brick wall. They tie their wall to the frame wall using sheet metal straps called (appropriately enough) brick ties. This narrow space, along with the weep holes, is what keeps the moisture that accumulates in the bricks from transferring to the wood frame wall behind them. Air can circulate behind the bricks to dry them each time they become moist.

If you have ever built a brick wall, or if you have ever watched someone do it, you will have noticed that quite a bit of mortar drops to the ground in the process. Even the best masons drop gobs of mud. The mortar that drops on the face of a brick veneer wall causes no problem -- it can be cleaned up -- but how do you remove the mortar that drops behind the bricks, building up to the point that it completely blocks the weep holes? Well, you don't, because there is no way to get into that one-inch space to remove it. So in most cases, the weep holes are left blocked, and very little air circulates behind the bricks -- and moisture certainly can accumulate.

Now moisture in wall cavities, as I have stated in other writings, is not a good thing to have. It breeds mold, mildew and rot. Furthermore, it invites termites, since those busy destroyers of houses must have (in addition to wood) water.

It is possible to erect a brick veneer wall without dropping significant amounts of mortar inside the wall cavity, but I assure you this practically never happens. Bricklayers, like everyone else working on a house in our area (and other areas, as well), are in a hurry.

Bricks can, of course, be sealed with masonry sealer, and this might have to be done if the wall faces toward the prevailing winds and rain is constantly driven into it. But sealing the brick will not eliminate the moisture from behind it and will, in fact, inhibit the drying process. The wall should breathe.

What to do? You can't get into the cavity to clean the mortar out without destroying the structure. What a dilemma.

Well, hold onto your hat, because here it comes! Install special vents higher up in the brick wall, say four or five courses up where there is no accumulation of mortar. These can be installed as the wall is laid up, or retroactively. They are made to occupy the space of one brick and are simply held in place with caulking. Space them about six to eight feet apart along the length of the wall. Obviously, individual bricks will have to be removed if the job is done after construction, but this is a small matter.

Will you find these vents installed on your newly built brick veneer tract house? No.

Why? They consume extra time and effort during the course of construction. Time is money in our business.

Incidentally, you won't see the brick vents on a great many high-end custom homes either. Many people consider them unsightly. Of course, moldy brick walls are not that aesthetically pleasing either, in my estimation. You can obtain the vents where bricks are sold.

Expansion Joints

Just as concrete slabs and other masonry structures expand and contract with temperature change, so do brick walls (and the concrete brick shelves beneath them). On my little tract house the brick veneer wall segments are not very long, and I'm not concerned about expansion and contraction. Some of you folks, however, have homes completely surrounded by brick veneer, and either vertical expansion joints were provided by the builder or they should have been.

Many times, if there is an offset or turn in a brick veneer wall, an expansion joint can be provided there. Otherwise, joints will occur every twenty feet or so in the length of long straight segments. The joints are accomplished by actually stopping the wall, leaving about a one-quarter inch gap, and then commencing the wall. The joints are then filled with an expansion joint material that resembles common caulking. The material is usually colored to resemble either the brick mortar or the bricks themselves.

If you don't have the expansion joints, don't worry about it because there is nothing you can do about it. Nothing practical, that is. If shifting and cracking occur, repairs can be made. Remember, the brick isn't holding up your house; the frame wall behind it is. That is not by any means to suggest that shifting and cracking are desirable elements in home construction.

Certainly, if you are building a new home, or if you are having one built, you should prevail upon the builders to consider the things we've discussed here. I've been prevailing on them for years, but I don't seem to have a lot of pull.

Retrieved 26 November 2002. http://www.johnbridge.com/brick_veneer.htm
Old 11-29-02, 02:13 PM
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You won't have much moisture,but you should have weep holes.What we do is lay rope behind the first course of brick so the mortar does not cover the weep holes.We leave every other head joint out for the weep holes.If I was real worried i would drill a few holes in the joints every 4 feet or so.You might have to go higher than the first course though. If they covered the back solid with mortar,it won't do any good.It's mainly for condensation.So at the very least the holes will give it some air to dry the moisture up faster.Even though the house is wrapped,you still need a way for moisture to escape...Hope that helps....A good way to get info in your area,is to stop by a house being built around quitting time with a 6pack of beer or soda and ask for some advice.Most masons will be happy to help if it's a quick question....
Old 12-04-02, 10:23 PM
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Weep holes are necessary. And as one reply noted they do get clogged. However the cotton rope set in the weep and laid about six inches will not clog. The water will be absorbed by the rope and "weep" out. As for the mortar behind the wall. No we( bricklayers0 don't stop it from dropping but "Mortar Net" does. It is used on most jobs today. For now just drill some holes, water will find them.

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