barriers to the rescue

By Lisa Petsko Sto Corp.

r[tHERE are many choices for I cladding available today. Some are more energy efficient than others and it's important for your builder customers, no matter what siding they choose, to protect their investment.

A waterproofing/air barrier is an important component to any job whether you are using stucco, EIFS, brick, stone or other siding options. A waterproofing/air barrier, simply put, helps solve envelope problems, no matter what cladding is used.

In all types of construction, the uncontrolled entry of water into the building envelope can result in deterioration of elements within the envelope. Proper integration of the air barrier/waterproofing membrane with other components and proper water management techniques, like the "3D" approach (Deflect, Drain, Dry). will effectively stop water penetration.

Deflect

Effective strategies for keeping water out of wall assemblies use the outermost face of the cladding and other exposed components of the wall assembly (e.g., windows) as the principal barriers against water penetration. This is the main water-shedding surface. Secondary barriers behind the cladding should be redundant layers of protection, in the engineering sense. In a properly designed and constructed wall assembly, the secondary protective layers should never get wet. Installing an airtight. waterproof membrane behind the wall cladding is an important component in the "3-D" defense strategy. The cladding itself, with an effective air barrier behind it. will deflect water from penetrations. This is the most important concept in stopping leaks.

Drain

Draining is less important than deflection, but if there is the assumption that some water might penetrate the cladding, for whatever reason, then provision can be made for gravity to direct it to a flashing and out of the wall.

Dru

Drying is the least important of the three functions. In the event that some penetration and drainage may occur. some water will be retained in the drainage cavity simply by surface tension. This water should be allowed to dry by diffusion through the cladding to the exterior, through the wall assembly to the interior. or by ventilation.

By using a waterproofing/air barrier and the cladding of your choice. you should rest easily that the completed project will be energy-efficient and long lasting.

- Lisa Petsko is product manager for Sto Corp., Atlanta, Ga., producer of a broad range of cladding and coating sysIents ; www.stocorp.cutr.

Heat loss through the walls, which accounts for up to 4O% of heat loss in non-EIFS construction, is also greatly reduced. EIFS dd to a building's R-value.

$ucco

Stucco, in most cases, is a blend of Portland cement, sand and lime that produces a durable, cost-effective cladding. It has many advantages, including low maintenance, and is easier to install with some new machine technology.

Using an elastomeric finish with a stucco product helps to maintain its beauty and durability. Stucco is available in thousands of color options and with many different coatings and finishes. An elastomeric finish can accommodate thermal movement caused by extreme tempeEture changes.

Brhlg Etc

Contrary to popular belief, brick does absorb moisture and needs an air barrier to be energy efficient and combat mold and moisture. Clay brick has a S,O(X)-year track record of providing sbelter that is durable, comfortable, safe and attractive. It doesn't rot or dent, resists termites, and is virtually maintenance free.

Water can migrate into brickwork, which handles moisture by either having a cavity or separation befween itself and the wall behind it or by being so thick that it acts as a barrier to the water. The best solution is to install an air banier.

Stone, wood, fiber cement, and vinyl sidings also can benefit from a waterproofi nglair barrier.

fN THE world of construction. the Ioverall value of iiberglass insulation is often taken for granted. Contractors often request the lowestpriced batt or roll insulation by its Rvalue, rather than requesting the best product for the job.

But newer, more advanced insulations can help keep walls free of moisture and mold and dampen noise. Although these products cost a little more than conventional insulation, they pay for themselves by reducing structural damage, limiting callbacks, and avoiding liability issues.

A closer look at their added benefits shows the collective importance of new forms of insulation and how easy they are to market.

Energy Efficiency

Obviously, fiberglass insulation is designed to resist the flow of heat. As heat is a form of energy, it always seeks a cooler area, flowing outward in the winter and inward in the summer. With properly installed insulation, a home has less heat flow and uses less energy for heating in the winter and cooling in the summer.

Because of this, fiberglass insulation is one of the most vital ingredients in an energy efficient home. Many of the other energy-efficient components will not function correctly without it. Installing quality fiberglass insulation in key parts of the home is One of the most affordable ways to conserve energy and help bring down heating and cooling bills. The insulation practically pays for itself in the long run.

According to the North American Insulation Manufacturers Association, for every etu invested in the manufacturing of thermal insulation, 12 nrus in energy savings are realized in the first year of service. On the whole, insulation saves more than 400 trillion BTUS a year.

Moisture Control

While energy conservation is a clear benefit of a properly insulated home or building, some newer insulation products can also help control moisture in wall cavities.

Water vapor is a guaranteed product of everyday life, coming both from human activities inside the house and humidity on the outside. It is naturally drawn through interior construction materials to cooler surfaces, where it can condense into liquid.

,, Water vapor moves from the exteri-