Bob outlines the different kinds of water that may creep into wall systems, and in particular, what can happen if intruding EIFS.
It's an understatement to say that there is a lot of current interest about the matter of water in relationship to EIFS. Most of this interest centers around leaks of liquid water as a result of precipitation. There is, however, a more complex and insidious form of water that has considerable significance to EIFS. That type of water is known as water vapor, and it is the subject of this months column.
As background, water exists in three forms: as a liquid, as a solid (as ice) and as a gas (as water vapor). Water vapor is not visible, and the amount in the air varies with the location, time of year, weather, and use of the building. For practical purposes the amount of water that is in the air, expressed as a percentage of the maximum amount that it can hold at that temperature, is known as the relative humidity. Hot air can hold more water than cold air, and hence as moisture-laden air gets cooler, some of the water wants to leave the air. The water that does leave the air can take the form of rain, snow or condensation.