Brick Leaks

By Tim Carter
©1993-2009 Tim Carter

Summary: Masonry structures are not waterproof. Water will pass through stone, block, brick and mortar. If improper installation of your masonry walls can't be easily repaired, you may be able to stop the leaks with high quality water repellents.

Related Articles: Brick Water Repellents, Wall Construction Tips, Preventing Leaks

DEAR TIM: Every time a wind blown rain saturates our brick veneer home water streams into our home. I have noticed that the wood floors in our living room are warping as well. The brick and mortar appear fine. What is causing the leaks? How should the brick have been installed? What, if anything, can be done to stop the water penetration? Brenda F., Brockton, MA

DEAR BRENDA: I hate to tell you this, but you have some very serious problems. If they are not corrected, serious structural failure will possibly be in your future. I'm quite confident that if I did a post mortem examination of your brick walls, I would find serious workmanship errors.

Virtually every brick wall will allow water to penetrate. The water has three possible paths. It can enter directly through the brick, the mortar, and/or the contact zone between the brick and mortar. The primary path of water into brick walls is the contact zone between brick and mortar and mortar joints that are not filled completely. Your wall leaks, I will wager, are most likely originating at the vertical joints between many of the brick. Bricklayers call these head joints.

Can you see what I see?  No water membrane covering the wood framing! What's more, do you see any weep holes? I sure don't.
Can you see what I see? No water membrane covering the wood framing! What's more, do you see any weep holes? I sure don't.
The quality, type, and moisture content of the mortar is a critical factor in preventing brick veneer wall leaks. The mortar for a brick veneer house needs to have a high lime and low cement content. The lime in the mortar, through the years, can actually heal tiny cracks that might develop between the brick and mortar. Mortar that is too wet or has too much cement can shrink as it dries. This shrinkage can produce tiny cracks that allow water to easily penetrate the wall.

Older brick houses usually were never a brick veneer. Often the brick walls were two, three and sometimes four brick thick bonded with lower strength, high lime content mortar. The inner courses of brick were very soft and absorbent. Rain water would collect within the wall and then be released to the atmosphere once the storm passed.

Modern single thickness brick veneer walls deliver the wind driven rain within a matter of minutes to the wood frame system just on the other side of the brick. This water needs to be collected and transported immediately to the exterior of the house. This is accomplished by installing high flashing materials at the base of the brick wall, above all doors and windows, and below all window and door sills. The flashing must be continuous and needs to be made from a material that allows joints to be permanently sealed. High quality brick veneer flashings can be made from modified asphalt and high quality polyethylene and copper / asphalt combinations. Do not use the low quality "garbage bag"or PVC type plastic. It is useless.

The exterior of your wood framed walls should also have been covered with a water resistant membrane. Overlapping horizontal pieces of time tested tar paper will work. However, there are many air and moisture barriers that will do as good a job or better at preventing the leaking water from contacting your wood framing. These moisture barriers must be installed so they lap over the wall flashings. Weep holes at the bottom of all walls and at the top of windows and doors need to be no lees than 4 feet on center. 2 feet on center is preferable. The cavity behind the lowest courses of brick needs to be free and clear of mortar droppings. This allows leaking water to easily escape through the weep holes. An ingenious saw-toothed plastic netting can accomplish this task easily. It fits behind the first few course of brick.

Your leaks may be able to be stopped with the application of high quality water repellents. These materials contain special chemicals called silanes, siloxanes, or a blend of the two. First you must closely examine your brick walls. Look for tiny hairline cracks in the vertical joints. Remove and install new mortar if you find obvious water entry points. After the joints dry, apply the water repellents according to the manufacturer's instructions. A second application may be necessary. If this does not solve your leak problem, I'm afraid that your only solution might be to re-install the brickwork properly.



Comments:

KarenAnne Bennett
22 Feb 2008, 17:38
Dear Tim, Last week we had severe rain storms and high wind. Today looking in my husband's closet the last garment and the wall were wet and full of mold. My house is brick built in 1960. I went out to check for cracks and mortar condition, everything seems fine. The problem must have started in the past few months to get that amount of mold it is in a two foot section right in the middle of the wall the ceiling appear dry the attic wall seems dry. Is there a special tool that can be used to detect leaks? Please advise me KarenAnne Bennett
AsktheBuilder
01 Mar 2008, 07:14
KarenAnne,
Read ALL of my Brick columns and follow the advice I have written out.
Emil Posavac
31 Mar 2008, 19:36
The weep holes in our brick house are too low. The previous owner covered many of them with mulch. I have been trying to uncover them. Is it possible to add higher weep holes using a masonry bit?
AsktheBuilder
03 Apr 2008, 09:00
Emil,
No. Water will travel to the lowest holes. You have far more serious issues with your grade. You need to read this past column:

http://www.askthebuilder.com/B67_Tips_on_Foundation_Soil_Grade_Around_House s.shtml
Erin
12 May 2008, 09:40
Tim

Our garage leaks due to our brick front veneer. The builder has been by to do work on the brick front, which lessened the leak but it isn't gone completely. We have a flashing above the garage and Tyvek wrap on the house, but we still have a leak. Any ideas on how to repair the leak? We recently got 4 inches of rain in one day, and now we have a leak in our basement ceiling along the first joist about three feet from the front of the house. Our basement is completely underground, could this leak be a brick front issue as well that has just made its way all the way down?
Poppy
25 May 2008, 03:53
2 days ago I had a water leak under my kitchen floor repaired that was also flowing out of my outside bricks...it is still flowing but is not as bad, we are having good weather at the moment and last time we had good weather it also seemed to dry out. How long would you expect the bricks to take to stop flowing water and dry out? I'm worried that there could be another leak. Thanks.
jennifer
26 May 2008, 16:30
We have a 12 y/o brick veneer home that we have owned for 3 years. There is currently water seeping out along an exterior wall under the weep holes in the brick. This has been going on for a couple days and we have never seen it before. We checked to make sure our water meter is not running. We have checked the wall inside for damp and checked plumbing fixtures inside the house and have not found a leak. It had not rained for at least a week and it was still wet, today it is worse, but it is hot, humid and it did rain a little last night. Any suggestions as to what else we might check and if not what type of professional we should call?
debs
21 Oct 2008, 17:04
dear sir
my nextdoor neighbours guttering is broken, when it rains it runs down the guttering which is in the middle of both our houses. they have the front gutter in their garden and i have the rear gutter in my garden. it is this front gutter that is broken. i have asked them if they will get it fixed as all down the front of my house is soaking wet, on days that it doesn't rain it leaves a patch that has a white outline right around this is from top of gutter to bottom.
will this cause any damage to my house i would be most greatful for any advice you have for me, as this problem has been going on for months.
many thanks debs

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