Water intrusion consultations for wet and leaking buildings

Water intrusion consultation for wet buildings and mold problems.

Excessive efflorescence and water intrusion The Chicago area housing market has a growing problem that has occurred over the past couple of years. Houses and condominium buildings have been experiencing a large amount of water intrusion. Sometimes this water is the result of a leaky roof, always the first suspect, but more commonly water is entering the building through the exterior masonry walls and stone trim. The picture, at left, is a fine example. Notice the powdery white smears on the brick. This phenomenon is called efflorescence. It forms when water that has been absorbed by the brick and stone (both are porous) and wicks outward. As the water travels, it dissolves some of the lime from the mortar. When the moisture reaches the outside surface and evaporates, it leaves these lime deposits behind. Efflorescence, in itself, is not a problem and can easily be removed (with a vinegar and water solution) but it is a sign of a larger underlying problem. The masonry walls are not properly constructed, sealed and flashed so excessive amounts of water are entering the building envelope. Water intrusion leads to deterioration of the masonry, rotting of the wooden windows frames and floor joists, stained drywall and promotes mold formation.

Our company has become (much to our surprise) this region's experts on water intrusion problems, unfortunately, because these problems are becoming more common. Here are some of the causes we have found:

Improper installation of coping stones: Buildings with flat roofs are built with parapet walls (around the sides of the roof). Proper flat roof parapet wall flashing detail The top of this parapet wall is equipped with a coping cap. Older buildings have coping tiles (rounded clay files) covering the parapet. Newer buildings use limestone or cast concrete coping stones. Whatever material is used, this coping is a cover for the top of the masonry wall and guards against rain and snow entering the top of the parapet. With clay coping tiles, the joints connecting the tile pieces will deteriorate, over time, and allow water to enter the wall. Non-professional repair attempts, using plastic roof cement, only aggravate the problem. These joints should be sealed with hydraulic cement and sealed with caulk. The newer buildings, with stone coping, are usually just not installed correctly. Proper installation calls for the stone to be beveled and sloped (so as to shed water), to be equipped with a drip edge (a small groove, cut under the edges of the stone, which will cause water to drip off and not be absorbed under the stone) and flashing under the stone (a rubber, plastic or metal membrane, as pictured above). If the copings are not properly installed and flashed, water will enter the top of the building's walls and wick through into the interior.

Improperly installed or missing flashing above windows and doors: Exterior wall openings (for windows and doors) are built using a lintel. This is an angled piece of steel that rests on the sides of the openings and supports the brick or stone over the opening (below, left). The area behind the lintel will accumulate moisture and it will flow down to the lintel. The lintel must have flashing (usually, a plastic membrane) that runs between

Brick veneer window lintel the lintel and overlying brick. Improper brick veneer door and window flashing This membrane will direct the water out, between the brick and the lintel so that it will not drip down through the top of the window or door frame. Many times, the builder does not properly install this flashing. Another overlooked construction detail is the fact that the lintel / brick space should be open. Many uninformed masons will grout (mortar) or caulk this gap closed. If this gap is sealed shut, the accumulated water will flow outwards and run down the sides of the openings (above, right/ Note the efflorescence on the sides of the door and window). Newer construction techniques also call for "weep wicks", small pieces of rope that hang out of the lintel space or at the base or sides of the walls. These weep wicks suck water out of the wall and wick it to the air, much like a paper towel will soak up water. Too often, these wicks are missing, improperly installed or not the recommended nylon or polypropylene, but just cotton clothesline. Cotton weep wicks will rot and deteriorate in a couple of years.

Unsuitable materials and improper construction detail: There are always new building materials coming on the market. Usually, these materials are superior (and less expensive) than the old Split faced block exterior wall covering materials and allow for a better building at a lower cost. But not all these materials are suitable for all climates. The Chicago area has a strange micro-climate. We have cold winters and hot, humid summers. Significantly, the past two winters (2006 - 2007) were fairly warm and wet. Masonry buildings absorb moisture and must be allowed to dry out. Contrary to what many people believe, most of this drying takes place during extended cold (and dry) periods during the winter. Because of these two wet winters, the masonry buildings in our area have not been allowed to properly dry out. A newer masonry product, called split faced block (right) has been used extensively over the past 10 years. This is a rough faced form of the old cinder block masonry unit. Split faced block is very porous and is not suitable for our wet climate. It must also be sealed with a penetrating sealer (and re-sealed every 4 - 7 years) or it will absorb a great deal of water. Many builders don't know this or were misinformed by their suppliers and told that the block had already been permanently sealed (not a true statement). Split faced block must also be installed only as a veneer in a double wythe wall (a two layer wall with the interior, structural wall actually supporting the structure and with a 1" air space between the two walls). Many builders have used split faced block in a single wythe wall or not properly constructed the wall with the required air gap and flashing between the walls. Many times, unprofessional masonry sub-contractors will not remove the excess mortar from between the two walls. This bridges the air gap and allows exterior wall moisture to leach through to the interior wall. Additionally, in condominium buildings, many condo associations are not informed that the block must be re-sealed. As a result, many of these buildings are suffering from "wet building syndrome", where moisture has been retained in the walls and has caused extensive damage and mold formation. Some buildings that we have inspected have been built so badly that they cannot be repaired and must be torn down.

We have a great deal of experience evaluating these types of problems and can provide an un-biased inspection using the latest technology. Our inspection report will provide you with quantitative information on the condition of the building and give suggestions on how the water intrusion problem can be solved. We also will be able to guide you to a number of forensic contractors who can properly, and finally, fix the condition.

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