Q: Why is it important to ventilate the attic and what is the purpose?
Attic ventilation provides year-round benefits to help fight heat and humidity in the summer, moisture buildup and ice dams in the winter. This helps to prolong the life of the building materials – including the plywood decking and the shingles, helps to improve the comfort level inside the home, and helps to lower the utility bills by reducing the load on the air conditioner and other appliances such as fans and refrigerators.
The summertime benefits of attic ventilation are often more obvious to the contractor than the wintertime benefits. That’s understandable. It’s not too difficult to realize the attic can get very hot in the summer, and if that hot air is not properly removed through ventilation it can become problematic. However, the wintertime benefits are less obvious, but – quite possibly – more important. That’s because the average family of four generates an estimated 2 to 4 gallons of water vapor each day through activities such as cleaning, showering, breathing, etc. Additional moisture is added by a humidifier in the winter months. Humidistat levels will need to be adjusted as the temperatures drop. Some of this water vapor rises into the attic. In the summertime, the outdoor air temperature – as well as the air inside the attic — is warmer than it is in the winter, and warmer air can hold more moisture than cold air can. But in the winter, the amount of water vapor that the air can hold is substantially lower. As a result, it can condense as frost or water droplets, drip onto the insulation, and, in time, contribute to mold, mildew, wood rot, stains on the ceiling, and poor indoor air quality.
Q: What’s the ideal way to ventilate an attic?
The attic ventilation system should always be balanced. This means an equal amount of intake net free area through vents positioned in the soffit/overhang or near the roof’s lowest edge and exhaust net free area through vents installed at or near the peak of the roof. This allows cool, dry air to enter the attic at the lowest point helping to remove any warm, moist air from inside the attic through the exhaust vents, creating a constant flow of circulation.
If the attic ventilation system cannot be balanced 50/50 (intake/exhaust), it’s better to have more intake than exhaust because it’s been our experience most houses lack proper intake. Additionally, any excess intake will become exhaust on the leeward side of the house because the intake vents on the windward side of the house will have “pressurized” the attic. As a result, the intake vents on the leeward side of the house will work “with” the exhaust vents to release air.
However, if the attic has more exhaust than intake it is potentially problematic because the exhaust vents can create a “vacuum” effect. For example, a ridge vent could pull air from its back side if it can’t obtain air from intake vents. Or, a wind turbine could pull air from a nearby wind turbine on the same roof because there is not enough intake low on the roof to pull from. If more than one type of exhaust vent is used (i.e. turtle vent and ridge vent on same ridge line) the exhaust vent will pull air from the closest source. In turn, creating very little air circulation and no real benefit to the structure.
Q: What causes ice dams?
Several factors attribute to melt snow and cause ice dams. Poor attic insulation, lack of adequate attic ventilation, and warm-air leaks into your attic cause the roof deck to heat up from the underside and melt the snow on your roof. The water (melted snow) trickles down the roof and freezes as the temperatures fall below freezing, or when the water reaches a colder surface, like your overhangs, where there is no heated living space beneath. As the freeze-thaw cycle continues, the ice becomes thicker and thicker, eventually creating a small wall of ice – an ice dam. Future melting snow will stop behind the dam, with nowhere to drain off the roof. Not only does this pool of water eventually refreeze into more ice, but also the water can work its way under the shingles (or other roofing material). At this point, the water can leak into your home or building, and quickly cause damage to walls, ceilings, insulation, and other areas. Shingles are designed to shed water, not to hold water.
Q: Where do my bathroom fans exhaust to?
More often than not, they are draped through the attic and nailed close to an exhaust vent. This can prove problematic for several reasons. First, the hot humid air from the fan can blow into the attic space, creating unwanted moisture that will freeze to the underside of the decking. On occasion, there are vents that have never had a flex tube attached, they blow into the insulation next to the unit creating moisture problems. Lastly, each bathroom fan should be independently ventilated to a specific type of exhaust vent. There are two ways of accomplishing this, one is a direct vent through the roof line and the other is a direct vent to the soffit/overhang area.
Q: What does hail damage look like?
Several types of shingles can react differently when struck by hail. As an example, hail damage to asphalt and composition shingles can look very different than hail damage to wood shingles. It is important to know the different effects of the damage to properly identify whether or not you have roof damage from a hail storm.
Asphalt and Composition Shingles Hail Damage
- Random damage with no discernible pattern.
- Hail hits that are black in color.
- Loss of granules, which may expose the roof felt.
- Asphalt and/or mat that appears shiny.
- Hail hits that are soft to the touch, like the bruise on an apple.
Wood Shingles Hail Damage
- Random damage with no discernible pattern.
- A split in the shingle where fresh cedar is clearly visible.
- A split in the shingle that has sharp corners and edges.
- A split in the shingle that has little to no deterioration at the edges.
- Impact marks or dents along the splits.
There are many other types of damage to shingles that can be mistaken for hail damage. For example, exposure to inclement weather and sunlight makes shingles brittle and gives them an aged appearance. This type of damage is normal wear and tear of shingles, which is sometimes misidentified as hail damage. Other types of normal wear and tear may include blistering, cracking, granule loss, flaking and algae. Manufacturing defects and mechanical imperfections in shingles can also be mistaken for hail damage.
Q: My skylight is leaking, should it be repaired or replaced?
One of the most frustrating problems in the average roof is the appearance of a serious leak around a professionally installed skylight. This is because such a leak causes water damage to the roof, the attic space, the materials in the ceiling, insulation, and the interior of the home beneath the leak. This is the reason that professional installation is often vitally important when a new skylight is purchased.
If it needs to be repaired after a leak has developed, it’s best for the homeowner to stick with professional assistance of someone knowledgeable to inspect the site for a comprehensive list of damages and needed repairs. The majority of skylights leak due to age and seal/gasket on the unit itself. The skylight is subject to extreme heat and cold causing expansion/contraction. As the gasket/seal expands and contracts it becomes brittle and cracks. At this point, replacement is the only option.
We have come across several DIY skylight installs over the years, (See pictures) and they all end with a professional contractor installing the unit correctly.
Q: I found shingles in my yard, are they mine? Will it leak?
When shingles blow off of a roof, most homeowners’ first questions are usually “Who can take care of this for me, how fast can you get it done, and how much will it cost?” But here’s the most important question a homeowner can ask:” What made my shingles blow off in the first place?”
Shingles stay attached to roofs in two ways. First, there are the nails holding the shingle to the roof deck. Second (and very importantly), there is an adhesive that seals the shingle and makes it stick to the shingle right below it.
There are some installation factors that come into play with excessive blown off shingles. One, “high nailed” shingles will not hold to manufacturers’ specs. Second, under driven or over driven pneumatically installed shingles. PSI levels on compressors can be set too high or low. Causing “nail pops” or “blow outs” on shingles. Last, location with respect to trees, neighborhood, and other buildings.
For example, a homeowner chose a 3-tab style shingle (that has a wind rating of 60 mph) for their new home in a new construction development surrounded by corn fields. There is no wind block of any kind and it’s likely this homeowner will see wind gusts above the specs for the product. This product is not a good fit for this homeowner, they will likely spend time and money on repairs that could have been avoided. Always check with a professional and ask what would be the best fit for your home.
Q: I have a small leak that shows up when the wind/rain blows hard out of a certain direction. What could it be?
We have found there to be several reoccurring problems that happen more often than others. Here are a few indicators for wind driven rains that only show up on occasion.
- Windows not sealed correctly and/or rotten window sills. As water sheets off the glass, wind pushes the water into cracks/crevasses that track behind the wall.
- Furnace flue cap/collar not secured properly or sealed can cause spots to pop up from time to time.
- A neoprene rubber plumbing boot that splits due to old age or deterioration.
- A vent that leaks sideways rain or powdery snow.