Although homeowners aren’t necessarily expected to climb on their roofs every season as part of regular home maintenance, there are some conditions that should be monitored to prevent roof damage and to help you get the longest life out of your roof-covering materials. Certain types of damage can lead to water and pest intrusion, structural deterioration, and the escape costly energy.
Hail and storm damage, known as weathering, can weaken a roof’s surface even if you haven’t lost any shingles/shakes/slates following a storm. It’s the most common source of environmental damage for roofs. Strong, sustained winds can cause uplift to the edges of shingles and shakes, which can weaken their points of attachment and allow rainwater and melting snow to reach the roof’s underlayment. Wind can also send projectiles through the air, which can damage every surface of the home’s exterior, including the roof. You should always inspect your roof after a heavy weather event, as far as it is practical to do so without taking any undue risks, to check whether you have lost any roof-covering materials, or if any parts look particularly weathered or damaged. A small fix now could prevent costly repairs later.
Tree damage results from wind-blown tree branches scraping against shingles and from the impact of falling branches blown by wind and/or because the nearby tree has dead branches that eventually break off and fall. Branches that overhang the roof should always be cut back to avoid damage from both abrasion and impact, and to prevent the accumulation of leaf debris on the roof, its valleys, and in the gutters, which will interfere with proper drainage and lead to pooling of rainwater and snowmelt. Of course, it’s especially important to make sure that tree limbs near the home’s roof and exterior are a safe distance away from utility and power lines. Tree-trimming is a type of homeowner maintenance task should be undertaken by qualified professionals, as it can lead to accidentally cutting off the service or power from an overhead line, being electrocuted by an energized line, being struck by an unsecured tree branch, falling off the roof or a ladder, and any number of similar mishaps that the homeowner is not trained to anticipate and avoid.
Squirrels and raccoons (and roof rats in coastal regions) will sometimes tear through shingles and roof sheathing when they’re searching for a protected area in which to build nests and raise their young. They often attack the roof’s eaves first, especially on homes that have suffered decay to the roof sheathing due to a lack of drip edges or from problems caused by ice damming, because decayed sheathing is softer and easier to tear through. If you hear any activity of wildlife on your roof, check inside your attic for evidence of pest intrusion, such as damaged insulation, which pests may use for nesting material. Darkened insulation generally indicates that excess air is blowing through some hole in the structure, leading the insulation to become darkened by dirt or moisture.
Algae, moss and lichen are types of biological growth that may be found on asphalt shingles under certain conditions. Some professionals consider this growth destructive, while others consider it merely a cosmetic problem. Asphalt shingles may become discolored by both algae and moss, which spread by releasing airborne spores.
Almost all biological growth on shingles is related to the long-term presence of excess moisture, which is why these problems are more common in areas with significant rainfall and high relative humidity. But even in dry climates, roofs that are shaded most of the time can develop biological growth.
What we commonly call “algae” is actually not algae, but a type of bacteria capable of photosynthesis. Algae appears as dark streaks, which are actually the dark sheaths produced by the organisms to protect themselves from the ultraviolet radiation of the sun. When environmental conditions are right, the problem can spread quickly across a roof.
Algae can feed on mineral nutrients, such as the calcium carbonate in limestone used as asphalt shingle filler. Calcium carbonate also causes asphalt to retain moisture, which also promotes algae growth, so shingles with excessive filler may be more likely to suffer more algae growth. The rate of filler consumption is slow enough that it’s not generally considered a serious problem.
Algae attach to the shingle by secreting a substance that bonds it tightly to the surface. Growth can be difficult to remove without damaging the roof. The best method is prevention. Algae stains can sometimes be lightened in color by using special cleaners. Power-washing and heavy scrubbing may loosen or dislodge granules. Chemicals used for cleaning shingles may damage landscaping. Also, the cleaning process makes the roof wet and slippery, so such work should be performed by a qualified professional.
Moss is a greenish plant that can grow more thickly than algae. It attaches itself to the roof through a shallow root system that can be freed from shingles fairly easily with a brush. Moss deteriorates shingles by holding moisture against them, but this is a slow process. Moss is mostly a cosmetic issue and, like algae, can create hazardous conditions for those who climb on the roof.
Lichens are composite organisms consisting of a fungus and a photosynthetic partner, such as green or blue-green algae. Lichens bond tightly to the roof, and when they’re removed from asphalt shingles, they may take granules with them. Damage from lichen removal can resemble blistering.
"Tobacco-juicing" is the brownish discoloration that appears on the surface of shingles, under certain weather conditions. It’s often temporary and may have a couple of different causes. After especially long periods of intensely sunny days, damp nights and no rain, water-soluble compounds may leach out of the asphalt from the shingles and be deposited on the surface. Tobacco-juicing may also appear under the same weather conditions if the air is especially polluted. Tobacco-juicing won’t harm asphalt shingles, although it may run down the roof and stain siding. Although it’s more common in the West and Southwest, it can happen anywhere that weather conditions are right. You can spray-wash or paint the exterior of the home to remove tobacco-juicing.
Your InterNACHI inspector should investigate signs of roof damage or deterioration before you call a roofing contractor. That way, you’ll know exactly what types of problems should be addressed before you break out the checkbook for repairs.
Roof Penetrations: Vents Homeowners don’t generally want to climb on their roofs to check its condition unless they’ve experienced a major storm or other issue that prompts them to investigate. This is smart because, as untrained non-professionals, homeowners are at greater risk for accidents and injuries than pros.
But it’s useful for homeowners to know what they’re likely to find if they do climb their roof—or have someone else climb it, such as an insurance adjuster or roofing contractor—so that they have some idea of what the components are and what they do, as well as when those components are damaged and creating problems down below.
The proper term for anything that pokes out of the surface of the roof is known as a roof penetration. Whether it’s a chimney, skylight or vent pipe, it falls under that category. As such, there are important elements related to the installation of all roof penetrations that prevent their premature deterioration, which means that your roof and the structure under it will stay dry and problem-free.
The most common type of roof penetration are vents. Every home has them. Vents are installed to expel gas or moisture of some sort from an appliance or area inside the house. Vents are also called flues.
Here are the most common types and their functions:
Vents can be double-walled or single-wall, depending on their purpose. Combustion vents tend to be double-walled. Some vents serve multiple items or appliances, but they tend to be of the same type. A vent that serves more than one plumbing fixture needs to be larger in order to move the gas at an appropriate rate.
Problems with Combustion Vents
If installed properly, vents tend to operate problem-free, but poor installation or materials can lead to issues, such as leaks, corrosion, and insufficient ventilation. That’s when the problems can affect the living space and appliances below. The most common issues occur with combustion vents.
To work effectively, a combustion vent has to draw adequately, which is the natural process that moves hot exhaust gases up and out the exhaust flue or vent. Another way to say it is that the vent needs to have a good draft. The effectiveness of the draft is influenced by several factors.
These factors include:
White deposits on combustion vents or on the roof below them are evidence that excessive condensation has been forming. This can be caused by a vent that:
Flashing for Vents
The critical installation that keeps moisture and the elements from entering the roof surface down the side of the vent is called flashing. Different types of vents require flashing that is appropriate for the type of vent installation, as well as of a compatible material so that it doesn’t cause galvanic corrosion or other issues that will cause the vent or flashing to deteriorate prematurely. Flashing may need to be on top of roof shingles or below stone tiles; a good roofing contractor who specializes in your roof’s material will know what type of flashing is required and how it should be installed.
Of course, a leak in the attic, or any signs of rust or staining on the vent, flashing or roof is a sign of a problem. If you do suspect a problem, your first call should be to your home inspector so that he can investigate it before you call a contractor. Most contractors are honest, but since the contractor has something to sell, and it’s in his best interests to find a problem that he can charge you to fix. Call your InterNACHI home inspector first; it’s his job to find the problem, not fix it.
Attic Insulation Heating and cooling costs can be slashed by up to 30% per year by properly sealing and insulating the home. Insulating the attic should be a top priority for preventing heat loss because as heat rises, a critical amount of heat loss from the living areas of the home occurs through an unfinished attic. During the summer months, heat trapped in the attic can reduce the home’s ability to keep cool, forcing the home's cooling system to work overtime.
The lack of adequate ventilation in insulated attics is a common problem. Ensuring that there is a free flow of outside air from the soffits to the roof vents is key to a well-functioning insulation system. Look behind the baffles to see if there is any misplaced insulation obstructing the natural air flow, and check the roof vents to make sure that outside air is exhausting properly. Also, look for spots where the insulation is compacted; it may need to be fluffed out. If loose-fill insulation is installed, check for any thinly spread areas that may need topping up. Finally, look for dark spots in the insulation where incoming air is admitting wind-blown dust and moisture into the material. Any unintended openings or holes caused by weathering or pest damage should be repaired first.
Installing Attic Insulation
The objective in an attic insulation project is to insulate the living space of the house while allowing the roof to retain the same temperature as the outdoors. This prevents cold outside air from traveling through the attic and into the living area of the home. In order to accomplish this, an adequate venting system must be in place to vent the roof by allowing air flow to enter through soffit-intake vents and out through ridge vents, gable vents or louver vents.
If there is currently a floor in the attic, it will be necessary to pull up pieces of the floor to install the insulation. In this case, it will be easier to use a blower and loose-fill insulation to effectively fill the spaces between the joists. If you choose to go with blown-in insulation, you can usually get free use of a blower when you purchase a certain amount of insulation.
When installing fiberglass insulation, make sure that you wear personal protective equipment, including a hat, gloves, goggles and a face mask, as stray fiberglass material can become airborne, which can cause irritation to the lungs, eyes and exposed skin.
Before you begin actually installing the insulation, there is some important preparation involved in order to ensure that the insulation is applied properly to prevent hazards and to achieve maximum effectiveness.
Step 1: Install Roof Baffles
In order to maintain the free flow of outside air, it is recommended that polystyrene or plastic roof baffles are installed where the joists meet the rafters. These can be stapled into place.
Step 2: Place Baffles Around Electrical Fixtures
Next, place baffles around any electrical fixtures (lights, electrical receptacles, etc.), since these may become hot while in use. Hold the baffles in place by cross-sectioning the rafters with 2x4s placed at a 3-inch clearance around the fixture. Cut the polystyrene board to fit around the fixture and inside the wood square you have just created.
Step 3: Install a Vapor Barrier
If you are installing insulation with a vapor barrier, make sure it faces the interior of the house. Another option for a vapor barrier is to take sheets of plastic and lay them between the ceiling joists. Then, using a staple gun, tack them to the sides of the joists.
Step 4: Apply the Insulation
Begin by cutting long strips of fiberglass to measure, and lay them in between the joists. Do not bunch or compress the material; this will reduce the insulative effect.
If you’re not planning to put in an attic floor, a second layer of insulation may be laid at a 90-degree angle to the first layer. Do not lay in a second moisture barrier, as moisture could potentially be trapped between the two layers. This second layer of insulation will make it easier to obtain the recommended R-value. In colder climates, an R-value of 49 is recommended for adequate attic insulation. In warmer climates, an R-value of 30 is recommended. Fiberglass insulation has an R-value of roughly R-3 per inch of thickness; cellulose has an R-value of roughly R-4 per inch, but it doesn't retain its R-value rating as well as fiberglass.
If an attic floor is in place, it will be easier to use a blower to add cellulose insulation into the spaces. The best way to achieve this is to carefully select pieces of the floor and remove them in a manner such that you will have access to all of the spaces in between the joists. Run the blower hose up into the attic. A helper may be needed to control the blower. Blow the insulation into the spaces between the joists, taking care not to blow insulation near electrical fixtures. Replace any flooring pieces that were removed.
Loose-fill insulation, either fiberglass or cellulose, is also a good option in cases where there is no attic floor. In such circumstances, you won’t need a blower; you can simply place the insulation between the joists by hand. You may also wish to even out the spread with a notched leveler.
Attic Access Pull-Down Stairs An attic pull-down ladder, also called an attic pull-down stairway or stairs, is a collapsible ladder that’s permanently attached to the attic floor. It’s used to access the attic without being required to use a portable ladder, which can be unstable, as well as inconvenient.
It’s typical for the homeowner, rather than the professional builder, to install the attic pull-down stairs, especially if it’s an older home or a newer home that’s been built upward in order to use the attic for living or storage space. That’s why these stairs rarely meet safety standards and are prone to a number of defects.
Some of the more common defective conditions include:
Call Tim at 503.349.0608 or email Tim@LegacyHomePDX.com