Real Estate Inspector
Roofing Tools Inventor
If your home has a steep sloped roof, and is over twenty years old, a 98% probability exists that your attic has excessive heat, leading to ice damming, resulting in subsequent water damage, and may have other serious problems identified by that heat, too. Even newly constructed homes may have serious attic heat problems!
Your response may be, "Oh, I do not live in a snow climate, so I do not have to be concerned about the heat that causes ice dams, right?" Wrong! Stop, look and listen. The problem of ice damming is a much deeper issue than may first appear and may be indicative of construction and health related problems other than just that of a "roof" problem, problems that can lead to delamination of the roof sheathing, wood rot of the roof rafters, failure of the insulation leading to higher fuel bills and the development of mold growth, creating health problems disguised as asthma, allergies, colds and sinus conditions.
(See March, 1999 issue of "Reader's Digest", pages 128 to 133, entitled, "Is Your House Making You Sick?")
Most people attribute the problem of ice damming to the "roofer", saying the roofer caused it, right? Wrong again! Although in some cases, the accuser would be right, in most cases, the accuser would be wrong. The roofer was not to blame for the ice damming and related problems! He may have done everything that was asked of him and expected by him when installing a roof, and still there may be ice damming and water leakage, not from unsatisfactory roofer workmanship, but rather as a result of one or more of the following subtle sources of heat, created by:
1. The Architect
2. The General Contractor
3. The Heating, Ventilating and Air Conditioning Contractor
4. The Insulation Contractor
5. The Electrician
6. And yes, let's not forget, the Homeowner, too!
Architects and designers are constantly trying to create aesthetically pleasing new homes. However, beautiful but complicated roof designs are not always fully compatible with a variety of climates. In fact, complex roof lines create some distinct and intrinsic problems regarding dissipation of weather related issues, such as ice and snow. The above, newly constructed property has several incompatible, climate-related design problems, including the channeling of snow and ice from two portions of the large, main, intersecting roof line, down and onto the lower roof area, entrapping snow and ice between the sidewalls of the main house and the sidewalls of the dormer. Compounding this problem is the reduction of adequate ventilation capabilities, reduced by the lack of adequate soffit inlet ventilation air flow, thus allowing excessive heat build-up, further adding to the creation of ice dams. This roof displays classic snow-melt patterns of unsatisfactory attic ventilation. However, other unsatisfactory conditions, leading to excessive attic heat, resulting in ice damming, were also present and will be discussed.
How does heat enter the attic?
How does heat exit the attic?These are two very important questions that must be asked of and answered by every construction design, whether it is for new construction, for additions, or for renovations. Without heat, there are no ice dams, no moisture condensation problems and no health issues!
The following are pictorial examples of some ways unwanted heat enters the attic space and some reasons why heat can not exit that attic space, too. Each of these conditions attribute to additional heat, the ultimate enemy of a healthy home.
Front Ice Dams
Ice dams were inevitable. Note the classic snow melt pattern, also seen on the home discussed above. Compounding this design problem even further, when the addition was installed, the entire house was re-sided. However, the original wood-covered soffit overhangs were never removed before installing the new perforated soffit vents, thus eliminating inlet air flow to the attic, an important and necessary element for all healthy homes.
The new addition had open, perforated soffit vents installed, but were then covered with insulation, eliminating needed and necessary inlet air flow to the attic. Soffit vent protectors were not utilized and should have been installed to help avoid insulation from blocking these vents.
The pink insulation was not installed according to specifications, and was out of position, allowing heat to enter the attic from the living space below.
12" of insulation, creating an R-38, is optimal. Remember, only have one vapor barrier and install it facing down to the heated surface. If additional layers of insulation are needed to attain 12", use either unfaced insulation or blown-in insulation.
Look at what further aggravated this particular ice dam formation...
If you design a recessed reading light over your bed, which is closely located near the roof, and which is on an outside wall, please install a double-walled, insulated lighting fixture that can then be safely insulated over to help reduce unwanted heat from entering the attic. [Note: This installation was also a fire hazard, noting that the insulation was packed against the unit, eliminating the required 3" clearance!] Two additional problems identified in this photograph are:
1. Insulation that is out of position, allowing heat to enter the attic, and
2. Insulation that is extended out over the soffit inlet vents, completely eliminating critical inlet air flow.
Air flow is easily explained using a catsup bottle as an example. When you open a new bottle of catsup and turn it over, and the catsup does not come out, do you know why? Because in order for the catsup to exit the bottle, air must enter the bottle. The same scenario holds true for your attic. In order for heated attic air to exit the attic, make-up air must be able to enter the attic. Having "only" inlet vents, or having "only" outlet vents is as good as having "no vents" at all! You must have both, inlet and outlet vents and in a balanced proportion, too. "Professional Roofing" magazine, published by the National Roofing Contractors Association (NRCA), had a very good article in their Residential Essentials section, entitled, "Ventilation guidelines", found on page 55 of their June, 1999 issue, for reference. Many web sites discuss the importance of attic ventilation, too.
The black area above the yellow insulation in the photograph is not black due to a lack of light. It is actually blacked by heavy black mold growth that is a serious health and safety issue for mold-susceptible people such as myself! This is an unhealthy home syndrome that must be corrected immediately. Remember, just because you are not allergic to molds today does not insure that you will not be allergic to molds tomorrow! If you are experiencing breathing and allergic type reactions, contact your doctor and then call someone to have your attic inspected for proper insulation, ventilation and heat sources.
Even further compounding the very unsatisfactory conditions of this attic is the use of loose, blown-in, fiberglass insulation, lacking a vapor barrier, which now doubles the amount of attic ventilation needed. Normally, the ratio of net free-air vent space to attic floor space being ventilated is 1/300, meaning that for every 300 square feet of attic floor space, one square foot of net free-air vent space must be provided. However, that ratio of required vent space now doubles to 1/150 for this type of insulation. Now you have a double whammy on the living conditions of this home!
Oh, and let us not overlook the heating duct near the roof line, too, which also adds additional heat... there is that word again... heat!
First, to avoid ice damming and the other problems, confirmed that every steep sloped roof has continuous soffit inlet vents. However, many homes designed and built in the 1950's were constructed without any soffit overhangs, making the installation of conventional soffit inlet vents impossible. Fortunately, the importance of attic air flow, even for homes built without soffit overhangs, is now becoming better understood. There are many new products on the market that will provide inlet air at the eave of the roof by bringing in the air from behind the gutters, through the roof sheathing, and under the shingle materials. Both roofing and carpentry work are required to install these new inlet vents, which are available wherever most roofing materials are sold.
Second, you must have ample outlet vents in the form of either 9" roof vents, or gable end vents, or ridge vents. Since heat, the primary culprit, rises to the peak of the roof, the logical outlet vent should be located at the peak of the roof, were an opening to the outside would then let unwanted heat exit, quickly, easily and efficiently, thus eliminating many problems. However, a closer look at the interior attic space of this newly constructed, three hundred and some thousand dollar home, reveals absolutely no outlet vents whatsoever! This is unsatisfactory and a disaster waiting to happen. Unfortunately for this newly constructed home and the new homeowner, it did, too and with major damage consequences!
This new home's ridge vent installation was unsatisfactory, noting that the roof sheathing was not properly cut away and removed. Other portions of this roof's ridge vent had both felt paper and shingle materials covering the opening, thus reducing exiting net free-air flow. Without exits for attic air, heat builds up, melting snow, creating ice dams and causing many other problems, too.
Winter is just around the corner. Correcting the above problems is easy during warm weather, but almost impossible to correct in cold weather. So, act now. If your home has experienced any of the above scenarios, start now to correct these problems before they become bigger problems. "A stitch in time saves nine."
Oh, about power vents - many times they won't do the trick. They are thermostatically controlled and thus do not work in the winter, when it is actually more important to ventilate your attic. When insulation gets wet, it loses some of its "R" value or resistance to thermal exchange, thus increasing the work required by heating and air conditioning systems. I have seen many a home look like a scene right out of "Dr. Zhivago's" Ice Palace!
Once again, the innocent roofer gets the blame!
In 1992, while still doing general contracting, I renovated an older, plank-constructed home for a client, including the installation of soffit vents, ridge vents and 12" of fiberglass attic insulation. In 1993, the northeastern USA had record snow fall, record cold weather and winter rains. My client was the only one in her neighborhood who had "zero", "nada", "no" ice dam leakage and no water damage that winter! Period.
Closing comment: In July, 2000, I was in the Columbia County Courthouse, Bloomsburg, PA, acting as an expert, defending a good roofer against alleged improprieties in his re-roofing installation. This case involved a job that had excessive heat due to no soffit inlet vents and no outlet vents of any kind, creating unsatisfactory attic ventilation (the lack of which was demanded by the owner, apparently under the misguided impression that vents cause heat loss and higher fuel bills???), had many large insulation gaps and openings, had an unsatisfactorily installed bathroom vent, and had an h.v.a.c. system in the unventilated attic, which had never been serviced, allowing overflow water leakage onto the ceilings below! This roofer is not to blame!
Ronald C. Hungarter
Real Estate Inspector
Roofing Tools Inventor
Home Inspector Instructor
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