Moisture can be a major contributor to indoor air health problems. Many times that moisture enters the house through the exterior siding In Florida the predominant siding finish is stucco.
Some of the most common issues with stucco occur because of moisture. Stucco problems like efflorescence, decomposition, peeling paint, rot, bugs, and mold usually happen due to the level of moisture that comes into contact with the stucco itself. In many cases, cracks can also occur, but often this is not related to moisture. While some stucco problems are not related to the way the stucco was put in place, many issues can happen with both conventional and newer styles of stucco if they are not installed properly. Improper flashing also is a key contributor to problems
Traditional Hard Stucco cement plaster (stucco) is a time-tested exterior finish. It consists of Portland cement-based materials and sand, mixed with water to form a workable plaster. Portland cement, the same material that is the basis for the hardened properties of concrete used to build super-highways, bridges, and skyscrapers provides strength, durability, and toughness in Portland cement plaster.
Portland cement plaster is applied either by hand or machine to exterior and interior wall surfaces in two or three coats. It may be applied directly to a solid base such as masonry or concrete walls, or it can be applied to a metal lath attached to frame construction, solid masonry, or concrete construction. Applied directly to concrete masonry, Portland cement plaster provides a tough 1/2-inch thick facing that is integrally bonded with the masonry substrate. When applied to metal lath, three coats of plaster form a 7/8-inch total thickness. A vapor-permeable, water-resistant building paper separates the plaster and lath from water sensitive sheathing or framing. Portland cement plaster has high impact resistance, sheds water, but breaths, allowing water vapor to escape. It’s a proven system that works in all climates.
A crack in cement plaster stucco is stress relief. The tricky part is to identify the source of the stress when investigating a crack on a stucco project. Finding the source of the stress can be made easier if you place all stresses into one of two categories: stress within the plaster membrane and outside stress placed upon the plaster membrane. This may be a bit simplistic, but it can help with a daunting task.
All buildings are subjected to a variety of stresses in various forms and this stress is often transferred to the plaster stucco membrane. Stucco is not and never was intended to be a structural material. While Portland cement stucco is similar to concrete in that they both have similar ingredients, stucco cannot be compared and required to meet the ASTM testing standards of structural concrete or load bearing masonry.
The first source of stress from within the plaster itself is considered shrinkage stress. All Portland cement shrinks as it cures. Controlling and minimizing that shrinkage is critical to minimizing cracks in both categories of stress. Some common mistakes made that add to shrinkage stress are:
• Poor mix ratios. Cement shrinks and sand does not. Some plasterers like a cement-rich mix because it works easier. Unfortunately, it also shrinks more. Sand volumes must stay up to minimize shrinkage.
• Lack of curing. Cement needs to set and harden. Excessive or fast evaporation of water from the cement plaster will cause shrinkage cracks. This is particularly true in the first day or two of application and with warm windy conditions. This can also happen to cement stucco applied over absorbent masonry-type surfaces.
• Poor sand quality. Sand with excessive fine materials, clay or too much dirt can all lead to volume loss of material (shrinkage stress). The clay absorbs excessive moisture and in turns shrinks more. Sand should have good gradation (variety of sizes) and be angular in shape. Example, round marbles don’t grip as well as triangular shaped particles.
• Excessive thickness. Since all Portland cement shrinks, trying to add a full thickness in one pass will also tend to shrink more and lead to shrinkage cracking. The old-timers referred to this as “single-footing.” It should be noted that there are some proprietary products with special additives that have had success in applying stucco in thicker applications with minimal shrinkage. These products do work and come with a price tag to match.
Cracks caused from any of these conditions are typically one-time events of stress. Shrinkage cracking tends to have a map-like cracking pattern. The bottom of a dried-out mud pond baked by the sun is an extreme example of this type of cracking. The fast dehydration and volume loss in material overcomes the strength of the mud paste. In cement plaster, the strength is gained over the first few days after application.
The second type of stress is from an outside source that overcomes the plaster membrane. Structural loads, lateral force racking, thermal changes, wind, lumber shrinkage and seismic events are all examples of outside sources of stress. These types of stress relief cracks tend to be longer and reach from one architectural break to another. Pinpointing the source of the outside stress is the most difficult of tasks.
What happens when the crack is not repaired?
The result can be a major problem especially with framed homes.
Even block homes have an issue, especially ones that have cracking occurring in the motor joints or between expansion joints
Inside humidity can be a major problem inside the home.
Definition: Humidity levels are recommended to be below 60% on the inside of the house. Per the EPA the
maximum humidity should be no more 60%. The Grams per pound (how dew Point is measured) should be no more than 90.
i. Dew Point: The dew point temperature is the temperature at which the air can no longer hold all of its water vapor, and some of the water vapor must condense into liquid water. The dew point is always lower than (or equal to) the air temperature. If the air temperature cools to the dew point, or if the dew point rises to equal the air temperature, then dew, fog or clouds begin to form. At this point where the dew point temperature equals the air temperature, the relative humidity is 100%. If there is then further cooling of the air, more water vapor must condense out as even more dew, fog, or cloud, so that the dew point temperature then falls along with the air temperature.
While relative humidity is (as its name suggests) a relative measure of how humid the air is, the dew point temperature is an absolute measure of how much water vapor is in the air. In very warm, humid conditions, the dew point temperature often reaches 75 to 77 degrees F, and sometimes exceeds 80 degrees. No matter how hot the temperature gets, a dew point temperature of (say) 75 deg. F always represents the same amount of water vapor in the air.
Per the EPA the maximum humidity should be no more 60%. The Grams per pound (how Dew Point is measured) should be no more than 90.
H2H has the top of the line moisture meters and we use thermal imaging to find issues many cannot. Do not wait till it is too late.
Thermal cameras are a very valuable tool in the hands of a qualified and trained expert. Is there a difference between you taking a picture with your phone and a professional photographer you hire? Of course there is. Now add on how to interpret the picture you are seeing. Anyone now can purchase infra-red cameras as the price has come down. A wrong interpretation can lead to a wrong conclusion which can lead to a costly mistake!
However only hire someone who has been certified from an accredited company.
H2H Indoor Air solutions has been trained and certified as a Level 1 Thermographer from FLIR the world leader in the manufacturing of thermal cameras not only to this industry but the US government and military.