One of the most asked questions about brick clad structures is: Don't brick buildings have much less problems with water and related damage? The answere is without a question, No. Typical of any siding material, when properly installed, none should have moisture related problems. In the case of a brick sided structure, if for example there is below grade framing, improper flashing details, inadequate provisions for drainage, leaking Windows and Doors, Patio Decks or other construction errors, substantial damage can be the result. One of the problems brick sided structures can experience is, if they should have moisture infiltration problems, they typically do not reveal interior wall condition until that damage is quite significant.
The primary protection against moisture infiltration in brick systems is the required air space between the back side of the brick and the weather barrier material. The intent of this detail is to provide for unrestricted water flow behind the brick to drain holes (weeps) at window/door heads, foundation or other base termination details within the structure. In the case of this structure adequate free drainage space was not provided behind the brick. Water that was not able to freely travel to drain ports degraded the weather barrier material where it then entered into the structures substrate. One must know and always remember that weather barrier materials are not waterproof. They are not intended to completely protect against moisture passage, they only manage displacement when used in conjunction with all other moisture protective design.
In this photograph the roof flashing was improperly installed allowing moisture to infiltrate to the back side of the brick were it penetrated the barrier and entered the interior of the wall. The prime cause of the problem was the excessive infiltration at the flashing detail. The secondary problem was a combination of an improperly installed barrier and lack of a functional drainage space. Although general conscience suggest brick is more forgiving that other siding materials that completly depends upon properly installed flashing details, free unobstructed air or drainage space and a wall barrier designed and installed to direct water to weep holes above wall penetrations and foundation/floorlines. It is important that all these details function together as an error in any component part of it will often result in failure.
Water related damage behind brick can often be very difficult to detect. In the process of repairing some dry rot damage to the door frame the repair contractor observed what he felt was some potential interior wall damage. Upon further examination it was revealed there was substantial hidden damage to the entire wall. Other than some dry rot detected at the door frame neither the contractor or homeowner had any idea this wall was on the verge of collapse. Note temporary floor jack installed at mid-wall for structural support.