The attic is usually the last place to visit during your home inspection. Sometimes just entering the attic is a chore itself and sometimes not even possible. Some home owners will renovate a home and during the process cover up the attic access. This happens more often than you would think and prevents the buyer from knowing the true condition of the attic.
The most common deficiency that I come across in attics is the presence of rodents. Homes that have fiberglass insulation will typically have a varied level of mice infestation in their attic. Rodent proofing your attic will take some time and dedication to the task. Seal all holes and cracks with steel mesh and / or caulking, do not use plastics, rubber or wood that can be chewed. Use traps placed near entry points and empty traps frequently.
Many home owners or contractors will enter an attic to install alarm wiring, cable or to install a ceiling fan. When inspecting the attic there are many times where a trail is visible where individual has walked or crawled along the rafters compacting the insulation. In fiberglass, and most types of insulation, the air trapped between fibers is what gives an insulation factor to product. When insulation is compacted the R value is reduced and you create an area of heat loss in your attic.
Many attics are built using engineered wood trusses. Engineered trusses are designed to support a roof and the normal snow load for your area. If you hang a storage unit from an engineered wood truss you are technically required to have an engineer or designer produce a detail of proposed construction and having drawing stamped. Because the truss is an engineered product it comes under Part 4 of the Ontario Building Code regulations.
Soffit venting is probably the most important factor in preventing ices dams and allowing proper ventilation of your attic. The average roof requires 1 square foot of ventilation for every 300 square feet of roof, low slope roofs require 1 square foot for every 150 square feet of roof. The vents must be 25% on bottom and 25% on peak of roof with the remaining installed where required. It is considered a good construction practice to install upper vents on same side of roof so that air does not just cross over from one vent to the other. Soffit baffles are required to be installed at the eave of the roof to allow air from vented soffit to enter attic. Most subdivision homes will have a soffit vent installed in every third rafter bay.
Many older homes will have vents discharging into attic. Plumbing vents, bathroom exhaust fans and kitchen range exhausts should all ventilate to exterior of house. Newer homes are required to have a insulated wrap installed on exhaust ducts to prevent warm air condensing in attic and forming ice and potential blockage in winter.
Failing to properly ventilate your attic can allow moisture to build up and will eventually cause mould and damage to your sheathing and shingles. Over the years the required insulation for homes has changed. Newer homes will typically have R-50 of insulation installed. If you have an older home your insulation may require upgrading and your ventilation checked to ensure it is adequate.
Urea formaldehyde foam insulation (UFFI) – What’s the Truth
Urea formaldehyde foam insulation (UFFI) has been used as an insulating material in North America since the mid-1960’s and in Europe for several decades. It is estimated that 100,000 homes in Canada and 500,000 homes in the United States are insulated with Urea Formaldehyde insulation. This form of insulation was used extensively in Canada and the U.S. during that time, especially during the period from 1975 to 1978. In Canada, the government offered financial incentives for its use and as with most government programs was poorly supervised allowing shoddy workmanship from poorly trained installers.
Urea Formaldehyde Foam Insulation (UFFI) was installed primarily in wall cavities during the 1970’s as an energy conservation measure. Its appearance is like ordinary shaving cream. Dry, it can be a white or tan colour, and fluffy like styrofoam. To ascertain if UFFI is present in a home samples of insulation must be taken for lab analysis.. It is made by using a pump set and hose with a mixing gun to mix the foaming agent, resin and compressed air. The fully expanded foam is pumped into areas in need of insulation. It becomes firm within minutes but cures within a week. UFFI is generally spotted in homes built before the 1970s; one should look in basements, crawl spaces, attics, and unfinished attics. Visually it looks like oozing liquid that has been hardened. Over time, it tends to vary in shades of butterscotch but new UFFI is a light yellow color. Early forms of UFFI tended to shrink significantly. Modern UF insulation with updated catalysts and foaming technology have reduced shrinkage to minimal levels (between 2-4%). The foam dries with a dull matte color with no shine. When cured, it often has a dry and crumbly texture.
Formaldehyde is also widely used in building materials. It is especially used in glue, foam insulation and pressed wood products, such as, plywood, particle board, paneling, wood finishes and furniture. Many floor coverings, like carpeting, padding, and adhesives also contain formaldehyde. Other products include paper products, cosmetics, deodorants, shampoos, fabric dyes, inks, and air and carpet deodorizers.
The United States had the first problem case involving Urea Formaldehyde which was installed in a mobile home. This mobile home was extremely air tight and the urea formaldehyde was apparently only half mixed and poorly installed. Although there were no directly attributable problems to the insulation the Federal Government banned its use as a precautionary measure. The fears of having a home with UFFI installed eventually created a loss in market value of the homes and the fear of cancer and other health problems coupled with the decrease in property value of homes insulated with UFFI, have given it a stigma from which it has never recovered. The Consumer Product Safety Commission banned the sale of UFFI in the United States in 1982. Shortly thereafter, laws were enacted to further ban its use. However, in April of 1983, the U.S. Court of Appeals repealed the law, due to insubstantial evidence of UFFI contamination.
Claimants in a Quebec court case took the Federal Government, manufactures and others to court in a record setting case which lasted about eight years. Unfortunately they could not find any homes where the formaldehyde gas levels exceeded the conservative amount of 0.1 parts per million. The court found there was no basis for a settlement and the plaintiffs had to pay most of the court costs.
Urea Formaldehyde insulation is still used in Europe where it is considered one of the best retro-fit insulation products. In 1983 the United States Court of Appeals repealed the law banning its use due to insubstantial evidence of UFFI contamination.
Perhaps no piece of equipment has changed the way energy professionals look at buildings more than the blower door. Over the past 15 years, entire diagnostic procedures have evolved around this relatively simple device that can make subtle, but measurable, changes in house pressures.
The blower door as we know and love it today springs from technology first used in Sweden in 1977, where it was actually a blower window. The idea migrated to the United States with Ake Blomsterberg, who came to Princeton University to do research in 1979. “We started using it because we were trying to understand infiltration,” says David Grimsrud, who was a researcher at Lawrence Berkeley National Laboratory (LBNL) in Berkeley, California, at the time.
According to Grimsrud, the Princeton researchers decided to mount the fan in a door because door sizes are more uniform than windows. Ken Gadsby (who was and still is at Princeton) recalls that they based the height of the lower door panel on his inseam length! With the help of the blower door, the researchers discovered that hidden leaks accounted for a much greater proportion of air leakage in a home than the more obvious culprits, such as windows, doors, and electrical outlets–a giant leap forward in our understanding of how a house operates (and malfunctions). Researchers at LBNL began to see how useful the blower door would be in weatherization and retrofitting work.
Blower door companies started springing up to serve the new market. LBNL energy researcher Max Sherman even got into the business of manufacturing blower doors for a short time. “The Department of Energy put out a solicitation to buy ten blower doors, so my father and I started a company and bid on the contract and we won,” Sherman remembers. These were big, heavy, clunky blower doors, made of plywood and Formica.
“We were all working out of our garages,” recalls Gary Anderson, cofounder of the Energy Conservatory. In 1986, Home Energy (then Energy Auditor and Retrofitter) identified 13 blower door manufacturers, with combined revenues for sales and testing nearing $10 million per year (see “A Healthy Outlook for the Blower Door Industry,” EA&R May/June ‘86, p. 6).
Home Energy
estimated that blower door sales alone reached $1.2 million in 1985. The focus at that time was on making more powerful fans in more manageable sizes.
And Then There Were Three
The industry has consolidated today, with only three North American manufacturers–the Energy Conservatory, Infiltec, and Retrotec–now vying for sales in a growing market.
The Energy Conservatory
Of the three, Energy Conservatory (manufacturer of the Minneapolis Blower Door) is easily the largest, selling 800 to 1,000 blower doors per year, along with Duct Blasters, digital pressure gauges, and other diagnostic tools and procedures.
The Energy Conservatory was hatched over lunches between partners Gary Anderson, then an auditor in St. Paul, and Gary Nelson, an engineer at the Minnesota Energy Agency, during which they would discuss the latest discoveries in residential energy efficiency. The blower door was one advance that captured their imagination.
“It got to be an expensive hobby,” Anderson recalls. The pair retrofitted a two-story garage to use as a calibration chamber and strove continuously to create a design that would be more practical for mainstream contractors. That meant it had to be less expensive, lighter, and easier to use. They worked to make blower door testing more friendly, accurate, and efficient, and helped develop protocols for weatherization programs to prioritize air sealing efforts.
In the late 1980s, the Energy Conservatory was involved in research that led to the understanding that duct leakage is a big problem–not just for energy waste, but also because pressure imbalances caused by the duct system can result in backdrafting and indoor air quality problems. This realization led to the development of a duct leakage testing fan (the Duct Blaster) and a digital manometer for more precise pressure measurements.
Infiltec
Infiltec sells blower doors, in addition to developing energy software and conducting indoor air quality studies for the Environmental Protection Agency.
“We sold our first blower door in 1980,” says Infiltec’s David Saum. Saum got into the business when his retired father was looking for ways to make his home more energy-efficient. Saum did some research and found articles on the Super Sucker, the window-mounted unit being used in Texas. “We decided that we could do better,” Saum says. In addition to blower doors, Infiltec now sells duct testers, mostly for testing ducts in new construction. Infiltec has recently taken its blower doors to Russia to test multifamily buildings there (see “To Russia with Blower Doors,” HE Sept/Oct ‘95, p. 8).
Retrotec
The Canadian firm Retrotec concentrates on selling units for testing fire protection systems, and on teaching HVAC contractors how to use the blower door to boost their business (see “HVAC Contractors Discover Blower Doors“). Retrotec has also been in business since 1980. The founders originally opened their factory because they needed blower doors to use in research projects for Natural Resources Canada (the equivalent of the U.S. Department of Energy).
“At the time, you couldn’t buy a blower door,” vice president Brendan Reid says. Retrotec now offers seven models–all different configurations of the same equipment. Four of these are used in testing industrial fire protection systems. The company offers an optional panel system made of molded plastic sheets, which Reid says installs faster than the standard doors and looks better, although it is less adjustable. Retrotec also sells a sealed smoke puffer, and a duct leak testing system for new construction. With nine employees and two independent sales contractors, the company has annual revenues of just over $1 million.
The Amazing
Shrinking Sucker
Old-timers in the industry can best appreciate the evolution of blower door technology over the years. They’re the ones who remember struggling with a heavy, bulky fan and door panels. “We had a chance to use one of Max’s blower doors,” Gary Anderson recalls, “and when we’d lug the blower door out there, two things happened. We’d be blown away by what we were learning, but at the same time, we were frustrated by how long it took.”
“Our first blower door moved 4,200 cubic feet per minute (CFM) maximum flow, weighed about 55 lb, and was about 28 inches long,” says Anderson. “Then we made a 10-inch long fan that moved 6,400 CFM, increasing flow by 50% with a shorter fan.” Refining the frame was the next major improvement in the blower door, and the Energy Conservatory went to a cloth-covered aluminum frame.
Infiltec’s design also evolved over time, switching from a DC to a much less expensive AC motor. They also introduced a flexible door panel and started using fan rpm instead of just pressure drop to measure flow, improving the accuracy of calibration.
HVAC Contractors Discover Blower Doors
Home Energy
’s readers are familiar with the use of blower doors for weatherization. HVAC contractors are also beginning to recognize the value of using blower doors to improve the quality of their work and to distinguish their company’s service in the market. Many have found that they can make more profit by fixing the problems than by selling higher-capacity equipment to provide thermal comfort in a leaky house. The blower door helps them do that. It also improves their ability to address such issues as backdrafting and indoor air quality.
People like John Tooley of Natural Florida Retrofit and Larry Palmiter with Ecotope have played an important role in bringing blower door testing to the HVAC industry. Since they and others learned of the hazards that can be caused by pressure imbalances in homes and ducts, they have worked to get the message out to people who work on houses. The energy waste and safety problems that can be diagnosed with pressure diagnostics are substantial, and contractors in many areas now understand that it’s good business to use blower doors in their work.
Blower door manufacturers provide training for those who will use their equipment. For example, Retrotec has specifically targeted HVAC contractors with a package that includes seven days of training, with manuals, videos, brochures, and telemarketing scripts. As Reid says, “We realized that if they didn’t have the training and support, they almost never used the blower door.” He adds that the 160 contractors Retrotec has trained in the last four years use the blower door to differentiate themselves from the competition and to add value to a proposal in a way that doesn’t cost them a lot of money. “We’re trying to show that a higher price is often a better value.”
Mediterranean Heating and Air Conditioning
Mediterranean Heating and Air Conditioning, in Canoga Park, California, owns five blower doors, and it didn’t take long for their investment to start paying off. “The first week after we got the blower door, we tested my house and found 500 CFM of leakage,” representative Mike Gardner relates. “I looked up in the return air chase and found it was open to the attic–a 12 inch by 30 inch space, open to the attic. The more houses we tested, the more we found that that’s common. Systems are losing 30% to 60% of capacity on the hottest days, and that’s normal!”
Gardner uses the blower door as an educational tool, to help customers understand that they are losing air. “We use Polaroid cameras in the attic to show them where the duct leaks are,” he says. After the Northridge earthquake, Mediterranean staff could easily verify whether ducts had been damaged.
“We’ve really had a shift in emphasis in what’s important in the HVAC business,” says Gardner. “Now the most important factor in how a system works is the integrity of the air distribution system. You have to ensure that integrity, so that people get the performance they expect from the equipment you install.”
Gardner’s company goes into about 10,000 houses a year. Blower doors will one day be a necessity in his business. “If you don’t understand the problems associated with duct leakage, you’re not going to be in the business,” he says. A year ago Gardner knew of only one other contractor in the Los Angeles area who had a blower door, “and it sat in the closet.” Now he knows seven contractors in the area who use them. “It’s an incredible competitive advantage.”
Holt Service Company
Before they started using blower doors in their business, “we could not find the problems because they were hidden under the insulation,” says David Holt, president of Holt Service Company in Columbus, Georgia. Holt, the third generation to oversee the operations of the family business, says his company has used blower doors for three years. “It makes us money and it solves a lot of problems for the customer. The true benefit to consumers is health, safety, and personal comfort. The financial aspects are nice, the icing on the cake.” He relates the story of a woman who had serious respiratory problems for years, which disappeared after he sealed her duct system. “Within about ten days, she called and said, `For the first time in ten years I’ve been able to sleep without getting up and getting my respirator.’”
“What’s it worth for you to sleep comfortably in your home all night and not wake up all clogged up?” Holt asks potential customers. “You don’t have to breathe all this dust and mold, don’t have to deal with all the moisture; you’re breathing cleaner, fresh air; and there’s no backdrafting.”
What’s Next?
“The equipment has pretty much evolved to optimum,” says Anderson. “The fan weight has dropped from 60 lb to 35 lb, at the same time increasing flow.” The next step is toward computerization and improved error analysis. A computerized, digital blower door will make data more accurate and repeatable at lower house pressures. It will also make it easier for researchers to track a wide variety of conditions. For example, David Grimsrud is now at the University of Minnesota, where he is conducting blower door tests by remote control, tracking measurements by computer to study backdrafting in buildings. His studies use the newest development by the Energy Conservatory: a 16-channel data acquisition system that processes input from carbon dioxide monitors and pressure and temperature sensors.
Super Sucker, the Sequel
In another interesting development, a monster blower door that takes the name of the window-mounted unit used in Texas all those years ago is being used to test large residential and commercial buildings in Canada. The Super Sucker is a whopping 55,000 CFM fan that is 40 ft long and 5 ft in diameter. It is transported to the site on a flatbed trailer, and it takes a team of five people to hook it up (to a pair of double doors) and perform the test.
A Blower Door for Windows
At the other end of the spectrum, the Canadian consulting firm CanAm Building Envelope Specialists Incorporated is marketing an individual window depressurization testing kit, called the MiniLab, which is used to identify and quantify air leaks around windows. This mini-blower door allows retrofitters to demonstrate improvements in air leakage when they replace or seal windows, and enables new home builders to specify and measure the performance of their windows.
The History of the Blower DoorWindow leakage is tested by installing 6-mil plastic on the inside around the window frame, cutting a hole in the middle of the plastic and attaching and sealing a tube in the hole. The hose is then connected to the blower, which pressurizes the space between the plastic and the window. The device has flow meters and a Magnahelic gauge, like a blower door, to measure flow in CFM at a given pressure. New standards in Canada require windows to meet air leakage ratings at 75 Pascals (Pa) of pressure.
Who’s Buying
Blower Doors?
“The market has changed from year to year,” says Infiltec’s Saum. “Originally it was entrepreneurs during the energy crisis; then it changed to utilities and weatherization agencies; and then a few years ago, to the fire protection business.” Blower doors are used to test fire protection systems that use halon gas instead of water (to prevent water damage in case of a fire). These systems used to be tested by setting them off and timing how long it took the halon to dissipate. The EPA banned this procedure when “it was found that halon was the worst ozone eater by a factor of ten,” says Saum. With a blower door, contractors can calculate how long it will take for the halon to leak out of a structure without actually releasing it into the atmosphere.
“To some extent, we have begun to saturate the weatherization market,” Anderson says. However, the blower door is also a valuable tool for HVAC contractors and builders. “Everybody who goes into houses and changes the way the houses operate wants to be sure they don’t do damage. HVAC contractors are becoming more aware than builders; they are much more familiar with the problems that can arise.” Retrotec’s Reid agrees, “There’s high potential because of the numbers,” he says, “with about 50,000 HVAC contractors in North America.”
“We’re moving to a time in housing construction when we’ll see more mechanical ventilation systems,” adds Grimsrud, requiring the near elimination of infiltration, and heralding a demand for infiltration testing in the construction industry.
Anderson points out that most of the people who stopped by the Energy Conservatory’s booth at a recent builders’ show weren’t familiar with blower doors, “but just about every one of them talked about moisture problems, backdrafting, fireplaces that won’t draw–all of which have to do with the airtightness of the envelope.”
“They definitely will benefit from this technology,” Anderson continues. “The option is to build the house and then deal with the problems that show up. A blower door gives builders some control over these problems, because they know how tight the house is, how to deal with duct leakage, and how to size a ventilation system.”
“The most important legacy of the blower door,” concludes Anderson, “is the evolution of the understanding of the house as a system and how you can characterize and diagnose the problems using pressure analysis.”
Visit the Barrie Home Inspector’s tips and maintenance site for more information on energy saving for home owners..
In Ontario the air barrier in a home is installed under the authority of the Ontario Building 9.25.4.3. Installation of Vapour Barriers
(1) Vapour barriers shall be installed to protect the entire surfaces of thermally insulated wall,
ceiling and floor assemblies.
(2) Vapour barriers shall be installed sufficiently close to the warm side of insulation to prevent
condensation at design conditions.
Where a vapour retarder is employed, the opposite wall surface must provide a permeable surface to allow drying to occur. Thus, in hot, humid, cooling climates, where a vapor retarder is employed at the exterior, the interior wall surfaces should be permeable. Novapor retarder paints, kraft-faced insulation, or vinyl wall coverings should be used. Conversely, in northern heating climates, with interior vapour retarders, the exterior wall coverings should be vapour permeable. This simply means that in warmer climates where cooling is the main concern, the vapour barrier would be installed on the outside of the insulation.
House wraps are a permeable surface which, while protecting your home from the elements allows moisture to pass. This allows any moisture that is between your vapour barrier and house wrap can escape and evaporate rather than collecting in your wall system. The primary attribute of house wraps is their ability to operate as air infiltration barriers while not forming an impervious vapour barrier. When placed over the exterior surface of the wall sheathing, the material allows moisture vapour to escape from the frame wall cavity while reducing convective air movement in the insulation, thereby helping to maintain the composite R-value of the wall.
The Dew Point of your house is the area where warm moist air will convert to moisture. The dewpoint is a measure of atmospheric moisture. It is the temperature at which air must be cooled in order to reach saturation (assuming that air pressure and moisture content are constant). As the surface of the earth cools at night, warm moist air near the ground is chilled and water vapour in the air condenses into droplets on the grass and other objects. Dew is particularly heavy on clear nights, when the earth cools rapidly. When a blanket of cloud insulates the earth, the cooling rate is slower. The greater the difference between the temperature and the dew point, the drier the air
When warm moist air infiltrates your vapour barrier, and passes through to your exterior wall, when it meets a cold surface or void, moisture is created as it cooled to its dew point. This can cause wet insulation, frost on exterior walls and in some cases even mould.
Prevention is possible by ensuring all your insulation is covered by a vapour barrier, most codes call for a minimum of 6 mm poly, and all penetrations are overlapped and taped by Tuck tape, the red tape not the silver duct tape of Red Green fame. All electrical boxes,windows, switches, andvent penetrations should be tightly sealed.
Basements are more susceptible to breaks in vapour barriers due to the fact that most services are located there and many installers fail to replace insulation and repair holes in vapour barriers etc. This can be increased if you have laundry facilities located in your basement and an open sump hole which contains water.
Humidity is the main factor of the creation of moisture and if you live in a climate where the humidity is less than 35% this would not be an issue for you. So if you have high humidity using a dehumidifier in your basement can alleviate these moisture problems.
Exterior Insulation and Finish Systems is an insulating, decorative and protective finish system for exterior walls that can be installed on any type of construction. It is the only exterior wall covering that insulates and provides weather protection in a selection of shapes, colors, and textures that can replicate almost any architectural style or finish material, or stand by itself as an architectural finish. While similar in appearance to stucco, EIFS is an exterior cladding system that consists of components and installation requirements very different from traditional stucco (see Figure 1 – Sectional View of a Typical EIFS Application). EIFS also requires very different care and maintenance than its “look-alike” cousin, traditional stucco.
In 1952, two significant developments took place that led to the development of EIFS in Europe. The first patent was granted for expanded polystyrene (EPS) insulation board and the first synthetic plaster, an organic plaster using water based binders, was developed. The use of EPS and synthetic resin materials together began in the late 1950s and in 1963
EIFS was marketed in Europe. EIFS answered a need in the European construction market for a material that could insulate older masonry structures and enhance their appearance. In Europe, the use of EIFS on stud/sheathing walls is rare, as most European buildings have solid masonry walls. European concrete or masonry substrates can function as exterior walls without the EIFS. European EIFS tend to have thicker and coarser finishes, which provides for better waterproofing. The systems used in Europe also feature the use of less portland cement and a higher resin content in the base coat, giving the system more flexibility and water resistance, albeit at greater cost.
The technology for EIFS was transferred to the United States in 1969, when Rhode Island-based Dryvit Systems, Inc. introduced EIFS in the U.S. During the oil crisis of the early and mid 1970s, EIFS becomes popular with energy-conscientious builders and buyers, who sometimes see energy bills halved. EIFS began by being used almost exclusively in the commercial building market, and was only gradually adopted for use in homes. By 1980, EIFS cladding accounted for one-half of 1 percent of the residential housing market, and by 1995 nearly 200 million square feet (18,580,608 m2) of EIFS were being installed annually on exterior walls in North America.
Also, in 1995, the industry suffered a setback when a number of EIFS clad homes in the Wilmington, North Carolina area were discovered with moisture damage behind the cladding. The damage was caused by poor construction detailing and practices, principally, the omission or improper installation of flashing in violation of minimum standards of construction set forth in building codes. A federal and several state class action lawsuits were filed, only one of which was certified (in the State of North Carolina). The North Carolina class action was settled by manufacturers. While the original problems were discovered first in North Carolina, it is really a nationwide issue.
In March of 1999, the NAHB (National Association of Home Builders) Research Center listed the most common problems they found that were associated with water intrusion in EIF systems as being:
Windows, Doors, Electrical Outlets Roof Flashings
Deck Flashings
Below Grade Installation
Projections, Vents
The NAHB commissioned study went on to state:
“. . .homes surveyed ages two to six are experiencing structural damage due to excessive moisture buildup within walls. The cause of the moisture accumulation is rain water intrusion from a combination of factors including: improper sealing at joints and around windows, doors, and other penetrations; improperly sloped horizontal EIFS surfaces; inadequate flashing at roof lines, dormers, decks, etc.; and window frames that leak into wall cavities.”
What Is EIFS (Exterior Insulated Finish Systems)?
While giving the appearance of stucco, EIFS is actually a multi-layered wall system that consists of the following components: Insulation Board – Made of polystyrene (or similar material), which is secured to the exterior wall surface. Base Coat – Applied on top of the insulation and reinforced with fiber mesh. Finish Coat – Applied on top of the base coat giving a durable, crack-resistant finish.
The first half of the acronym, “Exterior Insulation” is derived from the fact that the first component installed is a foam insulation board. The foam board is mechanically and/or adhesively attached to the exterior sheathing of the home. In this respect the foam board serves as an exterior insulating layer. Over this foam board is applied a synthetic base-coat material in which is embedded a fiberglass reinforcing mesh. This is typically referred to as the “base-coat”. On top of the base coat is applied one or more “finish coats”. This is the exterior layer that gives the product its stucco-like appearance. Hence the second part of the acronym “Finish Systems“.
EFIS provides many advantages that other exterior finishes and sidings do not. Chief among these are superior energy efficiency and great design flexibility. As a matter of fact, studies have shown that EIFS can reduce the air infiltration in a wall by as much as 55%, when compared to standard brick or wood construction. One should bear in mind that an EIFS system is a non-structural component of the wall. In other words, it is not designed to be weight bearing.
Most early EIFS employed a face seal approach to rainwater management, and was thus very susceptible to failure. Because of these early problems, most EIFS now incorporates some sort of a drainage plane to allow for moisture drainage. Newer installations incorporating this design could be considered concealed barrier systems. However, due to the nature of the product and the realities of the construction process, even newer drainage EIFS systems can experience problems:
“Short-cuts” are often taken in the application of EIFS systems, causing the primary face seal moisture barrier to fail and leak (lack of proper caulking, flashing, etc.).
The integrity of the second line of defense is highly dependent on correct detailing by the designer and proper installation by the builder and his subcontractors. Very often, flashings, housewrap, windows, doors, etc., are improperly installed.
EIFS does not breathe and will not allow trapped moisture to evaporate easily, which can cause great damage over time.
Because EIFS (Exterior Insulated Finish Systems) rely on a perfect seal at the exterior surfaces, they are susceptible to entrapment of moisture inside the system. Water can enter the system where seams and seals fail, where moisture migrates from inside the building and where punched openings (windows, doors, etc.) are present. Because of the low vapor permeability of the finish, water trapped behind the EIFS cannot dry out quickly toward the outside of the wall (see figure 1). Depending on the rest of the wall system design and installation, there may also be limited drying potential to the inside. Limited drying potential in combination with high leakage potential can lead to moisture buildup inside the wall, and eventually to mold growth and structural decay.
Why Most EIFS Have Failures
Since EIFS clearly provides many advantages, what’s the big deal? The basic problem begins with the erroneous belief that homes can be made to be “water proof”. The simple truth is, they cannot. For example, even when applied by professional caulking applicators, All caulk joints will eventually fail. . . .even those caulk joints made under laboratory conditions. No residential windows are fully waterproof. . . .they are designed and manufactured to a water-resistant standard. Some water will always find a way in. When it can’t get out, you have a problem.
Why Can EIFS Be A Problem?
Homes clad with EIFS (Exterior Insulation and Finish Systems) a.k.a. synthetic stucco have a very strong tendency to retain moisture between the sheathing of the home and the finish system. The design of EIFS, unlike other systems (brick, stone, siding, etc.), does not allow the moisture to drain out. The problem is water intrusion and entrapment in the wall cavities. The moisture can sit in contact with the sheathing for a prolonged period and rotting may result. Damage can be serious.
While a brick or stone wall will contain an internal drainage plane behind it and weep holes along the bottom edge to allow for water drainage, moisture intruding into the EIFS wall cavities is more damaging because it cannot readily escape back out through the waterproof EIFS exterior as quickly as it can through brick veneer, stone, or cement stucco, leaving the internal sheathing and wood framing vulnerable to rot and decay.
Successful installation of EIFS depends upon keeping water out of the wall cavities. Consequently, in an effort to keep the water out, an industry-wide installation standard was developed that details installation procedures to be followed. In conjunction with this, the EIFS manufacturers then trained and certified applicators to install their products and supplied them with materials which met specification standards.
But, here is where the system begins to break down, because unfortunately, the manufacturers failed to take into account the realities of residential construction:
Barrier type systems rarely work. The EIFS external barrier system depends upon a perfect external water barrier to keep water out of wall cavities. Since the outer shell is the only barrier against water intrusion, it must form a “perfect” barrier at “all times.” When there are so many entry points for water intrusion in the exterior shell of a house, this is an unrealistic expectation.
Lack of inspection and enforcement of standards. Most manufacturers, unrealistically expected that the building industry on its own (including public inspection departments), would maintain industry standards & specifications, provide oversight, and provide inspection of the EIF system as it was installed. Everyone thought that someone else was minding the store, consequently, the vast majority of EIFS applications nation-wide, have never been inspected. Compounding this problem is the fact that the EIFS manufacturers have failed to insist upon the very standards they helped originate, be met by the applicators they supply materials to.
Evolution of application guidelines. Another consideration is that guidelines for EIFS installation have been evolving over the years. An example of this is below grade termination of the EIFS. While not allowed by building code, early on, it was allowed by some manufacturers specifications. However, due to problems with this type of application nation-wide, in 1996 Dryvit Corp (one of the largest EIFS manufacturers), changed all of its specifications to require an 8 inch separation be left between the EIFS and soil (termite problems in the South & carpenter ants in the North, moisture wicking up into the EIFS, frost damage, inability of the EIFS to drain water away if it is buried, etc.). Unfortunately, this type of new information has been slow to “trickle down” through the information chain (from the manufacturer è distributor è applicator). Some distributors even claim their insulation-board doesn’t wick water, and consequently can be placed below grade (experience shows that it does, however).
Leaks and damage are hidden from view. There are few, if any, external visual clues to an early leakage problem. As a matter of fact, it can take years for an intermittent leak to evidence itself as damaged sheathing, window leaks, rotted framing, mold growth, etc. Many insurance companies, builders, and applicators may not take a leakage problem seriously, until they can actually see the damage. The reason for this “mind-set” is understandable, because no one wants to be responsible to pay for repairs that may be unnecessary. Unfortunately, by waiting until a problem is noticeable as visible damage, the word repair can become the word replace. What was once a relatively inexpensive repair has become a very expensive replacement.
Problems With Secondary Weather Barrier and the Inability To Drain
Most wood-framed residential homes require a secondary weather barrier to be placed over the sheathing before the exterior cladding is installed. This barrier protects the home from incidental water intrusion and allows moisture to exit the home by traveling on top of the barrier, keeping the sheathing and structural members relatively dry. Eliminating a barrier and rendering a substrate unprotected invites trouble, no matter what type of exterior cladding is used.
Due to the design of the EIFS, a majority of EIFS clad homes built before 1997 do not have a secondary weather barrier placed over the exterior sheathing. A large number of EIFS applications use an adhesive to fasten the two-foot by four-foot insulation boards to the sheathing. If an adhesive is used to hold the insulation boards to the sheathing, then a secondary weather barrier cannot be used. Any water that infiltrates the system will become trapped between the EIFS and the sheathing.
It is estimated that 95 percent of homes clad with EIFS in the United States are barrier-type. Most barrier EIFS projects are adhesively applied because it is less time consuming to install. Adhesively applied EIFS prohibits a vapor barrier from being installed. It also prevents many self-flashing windows from being installed properly since the sill flashing must be cut off to accommodate the adhesively attached foam board.
EIFS homes built before 1997 have a greater chance for moisture intrusion problems. Newer EIFS homes built since 1997 using “drainage EIFS” may have a reduced chance of moisture intrusion, but are not immune.
Lack Of Applicator Training
EIFS must be purchased from an EIFS distributor. The manufacturer or distributor trains applicators and issues certificates stating that the applicator has been properly trained. It is the responsibility of the distributor to ensure that EIFS is sold only to those certified applicators.
Not Following Manufactures Installation Guidelines
Deviations from Industry Standard guidelines during installation, is likely the largest contributor to EIFS cladding problems. EIFS application requires the strict observance of manufacturer recommended specifications and guidelines, and involves meticulous workmanship and attention to detail. When improperly applied, the EIFS cladding does not perform its intended function and can allow water to infiltrate behind the cladding, where it becomes trapped.
Due to the lessons learned during the early years of the industry, around 1996 set of “Installation Details” were developed by EIMA (EIFS Industry Members Association), that have since become the industry installation standard. Each manufacturer may have its own specific requirements as well. EIFS Installation Details are procedures outlined by the EIFS manufacturer that provide guidance to the architect, builder and applicator as to the proper installation of the product. All EIFS manufacturers have details and procedures that builders and applicators are expected to follow. Installation details are typically very similar among EIFS products and EIFS manufacturers, but there are differences.
A common misconception among some applicators is that the “Installation Details” are designed for specific parts of the country, exposed to certain weather conditions, and not to them. This couldn’t be farther from the truth, and has led to some expensive repairs having to be made. The Installation Details were designed to be used industry-wide, and are applicable whether the installation is in a northern cold climate, or southern warm climate. One should never make the mistake of dismissing as being insignificant, even some of the smaller deviations from the accepted industry installation standards. Unfortunately, there is a long history of applicators having done this in the past. . .to their great regret later on when the bills come due to pay for replacing the entire exterior. When installed properly, many EIF systems can perform well. However, EIFS is a very unforgiving product and even the smallest short-cut in installation standards and quality of components, can lead to big problems down the road.
The problem we face now is, sometimes an individual contractor may fail to fully follow the manufacturer’s installation guidelines. Often times only a portion of the guidelines are followed, materials from different manufacturers are inter-mixed, etc. This can allow moisture into the wall system. Once the moisture is in it can’t get out, which can lead to wood rot. Some of the more common installation “short-cuts” are listed below:
Foam insulation placed below grade. Prior to recent building code changes, the foam board insulation used in EIFS was placed on the wall below grade. It was discovered that foam in contact with the ground causes conditions conducive to pest infestations (termites, carpenter ants, etc.). With EIFS-clad homes, the visible evidence of infestation is blocked from view by the exterior siding. In fact, the exterior siding typically looks pristine and shows no signs of any problems. Behind the EIFS cladding, pests can live in a protected environment and then establish themselves inside the home.
Another problem with placing the foam below grade is the ability of water vapor to migrate upwards through the foam. When the temperature rises at the transition from masonry to wood, the water vapor condenses and causes water to settle on the sill plates and exterior band joist. If this water does not evaporate quickly, wood rot can set in and decay the structural members of the home.
Improperly flashed & caulked windows. Window leaks account for the majority of water damage in EIFS houses. The EIFS itself isn’t usually leaking; instead, water is entering between the window and the EIFS, or the window itself is leaking water. The solution requires a window flashing that works, as well as a correctly detailed joint between the window and the EIFS wall. Wherever a window, a door, or an electrical or plumbing fixture interrupts the EIFS surface, a proper joint must be constructed, that integrates a reliable flashing into the secondary weather barrier.
A very important component that is often missing in window detailing is the backer rod. The backer rod serves two functions: First, it prevents the caulk bead from adhering to the back of the joint, allowing the caulk to flex in response to thermal expansion and contraction and other building movements. If the backer rod is omitted, the caulk will adhere to the back of the joint as well as the sides, limiting its ability to stretch and guaranteeing premature failure. Second, it controls the thickness of the finished application of caulk, which should ideally be about half as thick as it is wide. More often than not, though, the caulk and backer rod are never applied at all. It is important to keep in mind that no residential windows are waterproof, they are designed and manufactured to a water-resistant standard. The very best windows allow some water into the wall cavity through their own joints, and “construction grade” windows may leak a great deal. The quality of windows installed with the EIFS is directly related to the amount of water that will infiltrate. For example, wood windows perform poorly, while welded seam vinyl windows perform substantially better than other window types. EIFS homes cannot be made totally “water proof”, and windows will leak. Regardless of how well the backer rod/sealant method seals the joints between window and the edge of the EIFS wall, windows will leak at some point (even those caulk joints made under laboratory conditions by EIFS industry engineers will eventually fail).
Flashings missing or improperly installed. are an important element in protecting your house from leakage, and should be utilized to properly direct water away from the structure. Some of the more common locations where they are required are: deck ledger boards, kick-out flashing at roof / wall intersections, at window and door heads, headers and other horizontal surfaces, etc. All too often, flashings are not installed, or installed improperly.
Roof termination. EIFS should be held off of roof a minimum of two (2) inches and backwrapped.
Expansion joints at dissimilar materials. Expansion-joints should be used where EIFS terminates, or meets a dissimilar material. The typical expansion joint is a flexible, watertight joint utilizing, backer rod and sealant. Expansion joints are typically 1/2 inch in width.
Backwrapping. Where the foam substrate terminates, it should be backwrapped, in order to provide for proper protection of the foam. Backwrapping also provides for improved attachment of the substrate to the sheathing.
Horizontal Surfaces: Trim Bands Quoins. There should be no horizontal (flat) surfaces. All surfaces should slope away from the structure.
Shared Responsibilities
An EIFS applicator is responsible for the application process-attaching the foam insulation to the substrate, applying the fiberglass mesh, embedding the fiberglass mesh with base coat and applying a finish coat. EIFS installers have little control over construction details designed to prevent water intrusion into wall cavities from roofs, even including those details which are required by some state building codes and by the specifications of the EIFS manufacturers. Many details outlined by manufacturers require the services of other tradesmen. A typical EIFS applicator does not install backer rods and sealant, but should install the EIFS so that it is possible to install these critical components. The builder is responsible for subcontracting the backer rod and sealant components. Flashing around windows, doors, decks, chimneys and roofs is the responsibility of the builder and his roofer. Unless the builder required the roofing subcontractor to install step flashing and (EIFS required) kickouts, it probably was not done.
The applicator should recognize improper flashing and not continue the application process until the problem is corrected. Unfortunately, this also slows down the overall building process. . .costing the home builder extra money. It doesn’t take an applicator long to recognize that an unhappy home builder may NOT call him to bid on the next project. According to the National Association of Home Builders Research Center,
Pressure Differentials
EIFS is basically a face-sealed system. The system relies on a water and airtight seal over the entire wall system. When this is achieved, an air cavity is created between the exterior sheathing behind the EIFS and the interior of the home. Positive air pressure changes caused by wind on the exterior of the home create a negative pressure in the wall cavity. Any breach in the barrier EIFS system will force air through that opening and into the wall cavity. When rain is introduced in this scenario, water (in its liquid form or as vapor), not air, is forced through any breach in the barrier EIFS. Many researchers indicate that the difference in pressure differentials is responsible for the majority of the water intrusions in face-sealed systems. Other wall claddings such as brick, lap siding, shingles and traditional stucco allow air to infiltrate, thus rendering the positive force applied to the building to be balanced.
Lack of Care and Maintenance
The beautiful architectural designs made possible by synthetic stucco systems make these homes very desirable and marketable. It is critical, however, to carefully maintain these systems to prevent water intrusion and deterioration. It is very important that the six following steps be followed to protect your investment.
Home Owners Responsibilities
Annually inspect all sealant around windows, doors, penetrations through the EIFS, EIFS transitions (such as EIFS to brick, EIFS to stone), and stucco terminations (at roof, at grade, at patios or walkways). Arrange for prompt repair of any areas of caulk that is split, cracking, crazing or is losing adhesion. Also, promptly repair any cracks in the EIFS.
Any leaks, cracks, areas of discoloration, mold or mildew should be promptly investigated by a certified EIFS inspector. Repairs should be proper and prompt.
Anytime you make a penetration through the EIFS such as to mount a satellite dish, add shutters, new wiring, cables, plumbing, security systems, etc., the perimeters must be sealed with a quality sealant approved for EIFS.
Modifications, additions or renovations (including roof replacement) to the structure of any kind should be inspected by a qualified EIFS inspector to ensure waterproofing of critical details is properly performed.
Periodic cleaning of the surface is necessary to maintain its appearance and prevent permanent staining. Pressure cleaning equipment must be calibrated to the EIFS manufacturer’s recommended pressure level (low) to prevent damage. Select a firm with experience in cleaning these EIFS systems. There are no products that are totally maintenance free, and EIFS is no different.
Maintenance Schedule. I would recommend setting up a maintenance schedule with an EIFS specialist to carefully inspect the exterior for damage, about every 1-2 years. Any needed repairs should be made at that time (usually just re-caulking, etc.). EIFS is the type of system where it is very important to catch any problems early-on.
With the winter season almost upon us it is time to discuss the re-occurring ice dams that frustrate many home owners. So lets start with the educational segment first.
Ice Dams are created when you have fairly large snowfall and the snow melts and re-freezes before being channeled away from your roof. This is usually caused by a warmer roof surface than the exterior temperature. This simply means that the temperature of your shingles is slightly above freezing when the outside temperature is below freezing. The “warmer” your roofs temperature is translates to larger ice dams. Non-functioning eaves troughs can also cause ice dams on your roof. Improper pitch or blockage due to debris etc will cause the appearance of ice dams. If you see heating cables on eave of roof it is a pretty good indicator that there is a problem with insulation or ventilation.
Poor ventilation and insulation is the common cause of most ice dams and is the culprit for creating a “warm” roof in the winter months. Heat escapes from your heated living space and gathers in your attic. (Remember heat rises) Poor ventilation does not allow for the removal of this heat which remains trapped in your attic.
So now we have the 3 basic requirements to start building our ice dam. In review they are:
1. Snowfall
2. Heat leaking into attic area.
3. Poor ventilation allows accumulation of heat in attic.
We are going to address the heat leaking into your attic and then the poor ventilation.
Insulation
During most of my inspections in the Barrie, ON area I have come to notice one insulation deficiency that appears over and over again. People, either themselves or hired contractors, enter the attic to do work and never repair the damage they have done to the insulation. Most of my clients have never been in their attics and just assume that all is well. Pot lights are almost always an indication that someone has been in the attic and maybe it is just bad percentages but over 75% of homes I inspect have large trails in their blown in insulation and areas where instead of 10 to 11 inches of insulation, only 3. There was even a popular franchise inspection company that “bragged” that they put a “tag” in every corner of your attic. When two thirds of your R factor is missing from areas of your attic you can safely assume that you will have heat escaping into your attic. You don’t need to hire a home inspector to check your attic; most attics can be completely viewed from the access hatch with a standard spot light.
So I would suggest to anyone out there that has an ice problem, that they first check their attic for missing insulation or un-even coverage.
Ventilation
The Ontario Building Code requires 1 square foot of ventilation for every 300 square feet. Twenty-Five percent of this ventilation is required at the bottom of your roof (soffits) and Twenty-Five percent at the top(peak). The remaining fifty percent can be spaced anywhere on your roof although most designers simply just put venting at your soffits and upper roof areas.
One main area of concern in ventilation is the soffit venting. As your roof rafters or trusses come down to your walls the area becomes very restricted and the building code even allows for lesser R values in this area do to space restrictions. Soffit baffles are used to prevent the insulation from completely blocking air flow from your soffits, thus allowing for air flow from your soffits through to your roof vents allowing for any humidity and heat to be dissipated to the exterior. I have seen homes in the Barrie area that the homeowner has taken the trouble to stuff insulation along their soffits thereby completely blocking all ventilation. Another frequent insulation blunder is people who insulate their garages and add an auxiliary heat source but totally ignore the fact that a garage is built with no ice shield on eaves and usually has no roof ventilation.
Once again a simple visit to your attic will ensure that you have adequate ventilation. Most soffit baffles are either plywood sheets extending down to walls or the popular Styrofoam soffit baffles. Usually they are installed in every third or fourth joist or truss space.
French Drains or similar devices have become popular for the disposal of downspout discharges around homes. I always recommend that home owners install a Tee at the top of their drainage pipe to prevent winter freezing problems. Water in your eaves and downspouts will always freeze at some time during the winter; the problem arises when the sun comes out and melts the ice in eaves troughs and downspouts but fails the thaw the underground drainage system. This is where the added Tee relieves the system by allowing the thawed run off to spill out the Tee, thereby prevent the splitting of downspouts and the possible creation of “ice dams”.