Guide to Rotting Brick Siding

5 years ago

Brick veneer siding has long been admired as one of the most stately materials to use when building a house. It’s classic and sturdy look add to not only it’s curb appeal, but perceived value as well. Brick siding does have some problems that other materials do not have and can be very costly to repair if performed incorrectly. If you have a brick house and are having any of these problems, this may help you determine why your brick is deteriorating.
Brick Half Walls with Brick Sills

Because the cost of brick is substantially more than most other siding options, many people that choose brick do what is called a half wall or a skirt. The brick is laid 4 feet up the wall and is capped with either a cast concrete sill pitched 15 degrees out to allow water to run off of it, or the brick laid on it’s side pitched 15 degrees out. Problems occur when brick sills are used because the water penetrates the mortar joints and sits on the bricks directly underneath, causing the bricks to actually rot, much like wood rots with significant water contact. Also, brick sills tend to allow water to travel into the top mortar joint and rot the first layer of brick underneath the sill. In severe cases where freezing occurs, the faces of the brick may be completely gone. This is called spalling and is a sign water damage to bricks. If brick sills are present on a home, they should be replaced with cast concrete sills as they will control the moisture and water much better, not to mention make the wall more sturdy.

No Weep Holes in Brick Veneer Walls

Brick veneer walls are made to allow moisture that penetrates through the mortar joints and is caused by temperature differentials to escape from behind the wall and run out of holes at the bottom of the wall called weep holes. There is a gap (or at least there should be) of about 1 to 2 inches to allow water to flow freely down the wall and out the weep holes. When there are no weep holes, the water builds up and has no where to escape causing the brick to absorb the moisture and decay. What’s worse is that because all of the excess moisture is sitting against the sheathing of the house, the wood sheathing is likely to rot and moisture will penetrate into the wall cavities. Once this happens this becomes a breading ground for mold.

Bowing Brick Walls

Bowing brick veneer walls are a sign of either poor installation or massive moisture that has caused the mortar to deteriorate around the wall ties that hold the brick onto the side walls. The middle bows out and stair step cracks are present in the middle of the wall and probably run to the corners or a single corner. if the cracks run through the bricks themselves, the bricks should be removed as there is extreme pressure from the wall not being properly supported and could fall and cause serious injury. This is more common on old commercial buildings from the later 1800’s and early 1900’s, but has occurred on newer structures as well.

Spalling Brick

Brick usually only spalls in climates where the temperatures freeze, but this can occur is areas where the brick is exposed to consistent moisture as well. Most of the spalling issues (spalling is when the face of the brick cracks off) are caused by poor mortar joint finishing. Straight recessed mortar joints allow water to penetrate the entire mortar joint and allow the water to sit on the brick causing major problems with the integrity of the brick. The best mortar joints are concaved inwards so the water drips along the mortar joint, but does not penetrate the mortar, causing the brick to last much longer.

Vines on Brick Walls

Vines that attach to brick walls are invasive and will literally become what supports the wall if the vines are allowed to take over. The vines grown int the mortar joints, popping out the mortar and shifting the bricks. This is usually not noticed because of the cover from the vines. Vines should not be grown near a house and should be cut back to ensure that the vines will not take over a wall of your house.

Even though this article is about the negative points of brick veneer and possible faults, it should be noted that the above scenarios only occur if the work is performed improperly. If the brick veneer is installed properly, using the correct masonry methods that have been used for over 100 years, brick veneer can be one of the most durable and long lasting siding choices there are.