moisture in wall behind brick front

Old 04-21-02, 01:03 PM
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moisture in wall behind brick front

Our house is 30 years old. We've lived in it for 12 years. We recently discovered mold in the walls of the house and have remediated the house but we are still getting an odor on the west wall which is part brick. It appears that the brick is drawing moisture or even getting water behind the brick when it rains and we've had a lot of rain recently causing more odor. We've been told we need clean the brick with muratic acid and put clear sealer on it. How will we know if the inside of the wall is dry enough for sealer. With the mold issue we wouldn't want to seal in any water in the wall. If there is moisture behind the brick when we seal it, will it dry fairly quickly. Also we were told to drill small holes in the brick at an angle to keep out rain and fill with cotton rope to keep out bugs so the moisture could escape. Is this a good idea or not? Would it help let the air into the wall cavity to reduce possible mold. We haven't removed the inside sheet rock to see if there is mold on the west wall in the basment. The brick is on the bottom part of the outside west wall and goes clear up to the roof in the middle section.

Old 04-21-02, 06:01 PM
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Moisture in wall behind brick

The moisture issue must be addressed first. Make sure gutters and downspouts are clear and carrying excess water away from the house. Sometimes when they get clogged, water can overflow the gutters and back up into the fascia or behind and down into the wall.

Typically, on a brick veneer construction in the first row of brick that is laid upon the foundation, they omit the vertical mortar joint every several bricks. These are weep holes that are suppose to allow any moisture behind bricks to escape and to allow the house to breathe. Most often these get clogged by mortar as the masons brick up the wall. The house is covered by sheathing and the brick wall is about 1" out from the house, tied into it with brick ties. The gap between the house and the brick allows moisture to escape and allows for air circulation. Mortar dropped by the masons can fill up this gap.

Now, if the house can't breathe and there is no place for the moisture to go, then you can have moisture problems and the associated mold/mildew problems. Sealing the brick will eliminate what few opportunities your house has to breathe and dry out. Sealing of exterior brick is typically not done unless it is on a wall that receives the prevailing winds and rain and the brick appears to be absorbing moisture. Do not seal until the moisture and mold/mildew problems are solved and you are certain everything has dried out.

Brick vents, available from brick yards, can be installed higher up along the wall. These are the size of a brick. A brick will have to be removed to install each vent with flexible silicone caulk. Vents will provide air circulation between the brick veneer and the house. Weep holes can be drilled every several bricks at the bottom of vertical mortar joints to make weep holes.

The only way to determine if mold/mildew are behind drywall is to remove it and make a visual inspection. Affected areas will have to be disinfected and allowed to thoroughly dry before reinstalling drywall. Drilling holes in drywall will allow air circulation into the wall cavity. Running a dehumidifier in the basement will reduce humidity and expedite drying out of the structure. Running fans will improve air circulation. If there are visible signs of mold/mildew on the drywall the affected area can be disinfected. This can be a warning that there are moisture problems in the wall.

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