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Brick Leaks

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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.

masonry-water-repellent masonry-crack-sealant

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21 Responses to Brick Leaks

  1. I would like to know the names of brick repellents for crumbling red brick
    If I use the repellents on the outside wall; how do I apply to already paints walls on the inside walls. Trying to drill out holes on the inside building to attach false wall but find the bricks are crumbling when trying to drill through.
    Any suggestion . Thanks Rita

  2. Tim,

    I have leaks coming into my brick in my attic. There is too much mortar on the back of the brick and very little tar paper. The water is going through the brick over the large deposits of mortar and into my house. I have a guy who wants to apply some kind of fiberglass mortar (or something ) to the inside (which is my attic) and then put up tyvec or tar paper. He advised that after this he would repoint the walls on the outside. What are your thoughts?

    • Tony, your question requires lots of typing, plus I have some questions for you so I can give you the correct answer(s). I only do pithy answers here in the comment section. If you want to protect the investment you have in your house and not waste time or money *hoping* you make the right decision, you should talk to me on the phone for just 15 minutes. It'll be the best investment you've ever made in your home!

  3. I have a garage with brick veneer that leaks into the garage from under the sill plate. The brick is below grade level which I think is the problem. Regrading really isnt an option. Is there a way to pull the dirt away where the brick meets the footing, place a waterproofing material at the seam then back fill? If so can you recommend a waterproofing material?

  4. Brick leaking can be resolved by wrap the house? Which material is the best choice ,of course ,not very expensive.

  5. I have a 1980s detached brick built house. In 2011 I had cavity wall insulation installed,since the New Year when we have experience
    wind driven rain the south facing wall has allowed water to leak into the conservatory over the back door and window lintel in several places through the brickwork. The same appears to be happening over the exposed windows. Any advice would be appreciated.

  6. Our house is all brick built in 1985

    When it rains I have a 5 X 9 foot section where all exterior bricks are wet . This section of brick is between two sliding doors leading out to a concrete patio in our basement. A couple of years ago we replaced the carpet in that basement and I did not see any water damage on the concrete floor.

    Over the past year, the section of brick that becomes wet is increasing. It is not getting any wider and stops right before it reaches either of the sliding doors. But, it is getting higher and starting to reach up to the first floor brick in that area. We have a wooden porch coming out from the brick wall above this area but I have always kept it heavily caulked where the porch attaches into the brick wall.

    The brick and mortar looks to be in pretty good shape.

    What do you think? Do you think a water repellant might fix this?

  7. We installed 80 brick mailboxes in our neighborhood. There is door, but no mailbox insert (just concrete). We get wet mail from condensation.

    THe opening is 7 by 7 inch and I wondering what is best option to tackle this. Tried to find 7 by 7 mailbox insert, but can't find. thoughts to eliminate wet mail due to moisture in brick unit?

  8. Hi ive just taken my skirtin.boards of and noticed on my main back wall were the wall meets the floor there are wet patches and i dont no what to do

  9. I live in a home built around 1890. When there is substantial rain or snow melt, I can actually see the areas where water is coming in around the bricks in our basement "walls."

  10. Just bought a house with brick veneer. The 6 inch thick concrete driveway have been cast against the wall covering well above any weep holes. Any suggestion how to best fix this?

  11. My back yard has a red brick wall that is firmly on my land. Sometime in the past (before I bought the house) my neighbor built a garage/ in-laws apartment using the brick wall as one of the walls of the house. Now they are getting water inside their in-law house where a 30foot tree has grown close to the wall. Needless to say they want to cut down the tree to fix the wall. My question is can they fix the wall from their side by breaking loose the two layers of brick from their side and then re-doing to mortar work for the impacted area's? Or is there another solution that can be done without cutting down the tree.

    Thank you

  12. I am looking to buy a house that has a concrete patio above the garage. The patio has brick pavers. During a heavy rain, water leaks through the patio into the garage. Is this going to be a costly repair?

  13. Thanks, Tim. I have done a lot if searching about the leaks from the top of my windows (brick exterior) with no good explanations until I stumbled on yours. Thanks.

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