by Michael Chotiner of The Home Depot
Stains on asphalt roofing shingles make a house look shabby, which detracts from its value. In some cases, stains are merely a cosmetic issue. But sometimes they’re symptomatic of a problem that, if left unchecked, can lead to more serious damage and, eventually, roof failure. It’s not always hard to distinguish the causes of stains, nor, in most cases, to get rid of them and prevent the stains from recurring.
Common Causes of Staining
Dark stains on an asphalt roof could be caused by a number of conditions, including:
Eroded mineral surface. If the roof-covering material has been on the house for 15 years or so, it could be that the surface granules are wearing off the shingles and the asphalt base is starting to show through. On older roofs, you may additionally see cracked and/or shingles with curled edges. If you determine that age and wear are the causes of darkening, it may be time for a new roof.
Algae growth. More often than not, blue, green or black stains on an asphalt-shingle roof are caused by algae. Algae staining begins with small spots which, over time, can develop into streaks. Algae stains, which are often mistaken for mold or mildew, aren’t harmful to anything other than the appearance of asphalt shingles, but nobody likes the look.
Moss. Green, velvety masses of moss often grow on north-facing roof surfaces and on tree-shaded roofs. Unlike algae, moss left on roof surfaces can develop beyond an aesthetic problem. It can infiltrate the roof structure underneath the shingles and make their edges lift and curl, which can lead to cracking and blow-off during high winds and storms. Heavy moss growth can actually form dams that can cause water to back up under the shingles and damage the roof deck. It’s best to clean moss off a roof as soon as you notice it’s growing there.
Both algae and moss can be easily removed from asphalt shingles with a 50/50 solution of chlorine bleach and water. Laundry-strength bleach is sufficient, or you can opt for any of a number of proprietary roof cleaners, some of which don’t contain bleach, lye, or other potentially harmful chemicals.
Since bleach and some cleaners can be harmful to plants and humans, it’s a good idea to take some precautions when working with them, including the following:
- Wait for a calm, windless day to clean your roof.
- Spray landscape plants near the house with water and cover them with tarps to protect them from chemical overspray and runoff.
- Wear protective clothing, including long sleeves, pants and gloves, as well as goggles to protect your eyes, and shoes with high-traction soles.
Before climbing up to clean stains from your roof, be aware that about 30,000 people fall off ladders and roofs each year. Consider using a safety harness, just as the pros are required to do, and follow the common-sense rules for properly positioning and using a ladder, which can be found in InterNACHI’s article on ladder safety. Also, be sure to notify someone that you’ll be on your roof. In case of an accident that incapacitates you, you’ll want someone to know where to look for you.
Upgear by Wenner Safety Harness (photo courtesy of The Home Depot)
How to Clean Algae and Moss from a Roof
Apply the bleach solution with a garden sprayer. Let it stand on the surface for about 20 minutes, then rinse it off with spray from a garden hose. Don’t let the bleach solution stand on the roof for more than 30 minutes or so without rinsing. And don’t use a pressure washer, which can damage the shingles by removing their protective layer of asphalt granules.
If accumulations of algae or moss are heavy, at least some of it should wash off the roof surface right away with the stream from the hose. You can try brushing off algae and moss with a brush or broom with medium-stiff bristles, but don’t scrub too hard. You don’t want to separate the mineral granules from the shingles.
If chunks of algae or moss or heavy stains remain on the surface after rinsing, let the roof dry, then spray on the bleach solution again. Wait 30 minutes and rinse. Don’t worry if some staining remains after the second rinse. It should wash off over time with exposure to rain and sunlight.
How to Prevent Algae and Moss Stains from Recurring
Algae and moss tend to grow roof surfaces that are shaded and retain moisture. So, it’s a good idea to cut away tree branches that overhang the roof and block sunlight. Keep the roof surface clean by blowing off leaves and fallen branches during seasonal maintenance.
The red lines indicate where to install sacrificial metal strips
to prevent algae and moss growth.
For long-term stain prevention, have zinc or copper strips installed under the cap shingles, leaving an inch or two of the surface exposed at roof peaks, along hips, and under the first course of shingles at the base of dormers. Copper and zinc are sacrificial metals that shed tiny bits of their surface with each rainfall. The metals coat the roof and inhibit organic growth for many years.
Following these maintenance tips can help homeowners enjoy an attractive roof. They can also help extend the roof’s service life, which is important whether you plan to stay in your home or sell it in the future.
There’s nothing like coming home and warming up next to a roaring fire during the long, cold months of winter, or even chilly evenings in any season. Long commutes to work in the cold and the increasingly short hours of daylight in the fall and winter are made more bearable by the comfort and familiarity of family gatherings by the fire. It may be for this reason that some type of wood-burning enclosure has remained a staple of many households, even though open fire is no longer a necessity for cooking and heating. With this in mind, let’s take a look at one of the more modern options available, the factory-built fireplace.
What is a factory-built fireplace and how does it differ from a masonry fireplace?
The traditional masonry fireplace is based largely on the innovations of Count Rumford, an 18th-century inventor. His applied theories on thermodynamics led to the design of a restricted chimney opening to increase updraft, which allowed fire to burn in an enclosure without smoke filling the room. Rumford’s design quickly achieved wide popularity in London households, and he became something of a celebrity as news of his innovation spread.
Factory-built fireplaces are also often called “zero-clearance” fireplaces because of their minuscule safe-clearance requirements. An insulating air blanket is incorporated in the design to keep the outer wall of the fireplace cool, which allows safe installation in very close proximity to wood framing. In general, ½-inch of clearance to combustibles is required around the outside of the firebox enclosure, and 2 inches of clearance are required around the chimney, except where the firestop is installed if a chimney passes through two levels of a house. Different manufacturers may have different suggested clearances, and it is important for installers to note this for proper and safe installation.
Safety and Maintenance
Factory-built fireplaces pass rigorous testing standards established by the Underwriters Laboratories and the American Gas Association. Properly installed, factory-built fireplaces have an excellent safety record. However, as in any situation where an open flame is involved, there are some things to keep in mind in order to avoid any risk of fire hazard.
If the fireplace is installed on top of any combustible material, such as carpet or wood, it must rest on a metal or tile panel that extends the length and width of the appliance.
Any combustible flooring near the fuel opening must be insulated with non-combustible floor protection.
Room air-inlet and outlet grilles must be unobstructed.
The same fire-safety precautions that are used for a traditional fireplace should be observed when a factory-built fireplace is in use.
- It should be connected. The connection is usually behind the dryer but may be beneath it. Look carefully to make sure it’s actually connected.
- It should not be restricted. Dryer vents are often made from flexible plastic or metal duct, which may be easily kinked or crushed where they exit the dryer and enter the wall or floor. This is often a problem since dryers tend to be tucked away into small areas with little room to work. Vent elbows are available which is designed to turn 90° in a limited space without restricting the flow of exhaust air. Restrictions should be noted in the inspector’s report. Airflow restrictions are a potential fire hazard.
- One of the reasons that restrictions are a potential fire hazard is that, along with water vapor evaporated out of wet clothes, the exhaust stream carries lint – highly flammable particles of clothing made of cotton and polyester. Lint can accumulate in an exhaust duct, reducing the dryer’s ability to expel heated water vapor, which then accumulates as heat energy within the machine. As the dryer overheats, mechanical failures can trigger sparks, which can cause lint trapped in the dryer vent to burst into flames. This condition can cause the whole house to burst into flames. Fires generally originate within the dryer but spread by escaping through the ventilation duct, incinerating trapped lint, and following its path into the building wall.
M1502.5 Duct construction.
Exhaust ducts shall be constructed of minimum 0.016-inch-thick (0.4 mm) rigid metal ducts, having smooth interior surfaces, with joints running in the direction of air flow. Exhaust ducts shall not be connected with sheet-metal screws or fastening means which extend into the duct.
M1502.6 Duct length.The maximum length of a clothes dryer exhaust duct shall not exceed 25 feet (7,620 mm) from the dryer location to the wall or roof termination. The maximum length of the duct shall be reduced 2.5 feet (762 mm) for each 45-degree (0.8 rad) bend, and 5 feet (1,524 mm) for each 90-degree (1.6 rad) bend. The maximum length of the exhaust duct does not include the transition duct.
- The IRC will defer to the manufacturer’s instruction, so if the manufacturer’s recommendation permits a longer exhaust vent, that’s acceptable. An inspector probably won’t have the manufacturer’s recommendations, and even if they do, confirming compliance with them exceeds the scope of a General Home Inspection.
- The IRC will allow large radius bends to be installed to reduce restrictions at turns, but confirming compliance requires performing engineering calculation in accordance with the ASHRAE Fundamentals Handbook, which definitely lies beyond the scope of a General Home Inspection.
M1502.2 Duct termination.
Exhaust ducts shall terminate on the outside of the building or shall be in accordance with the dryer manufacturer’s installation instructions. Exhaust ducts shall terminate not less than 3 feet (914 mm) in any direction from openings into buildings. Exhaust duct terminations shall be equipped with a backdraft damper. Screens shall not be installed at the duct termination.
M1502.3 Duct size.
The diameter of the exhaust duct shall be as required by the clothes dryer’s listing and the manufacturer’s installation instructions.
M1502.4 Transition ducts.
Transition ducts shall not be concealed within construction. Flexible transition ducts used to connect the dryer to the exhaust duct system shall be limited to single lengths not to exceed 8 feet (2438 mm), and shall be listed and labeled in accordance with UL 2158A.
Ever wonder about your house number? Often, the previous owner installed the number and the new owner never had to think about it, leaving them clueless as to why it was placed where it is or why a particular color or size was chosen. These numbers are more important than you probably realize, and a lot of thought goes into making sure they are visible.
Consider the following recommendations:
- The numbers should be large, within reason. Try to make them at least 5 or 6 inches tall. Smaller numbers may not be visible from the street if you have a large front yard. Replacement house numbers can be purchased from hardware stores and online.
- The numbers should be of a color that contrasts with their background. Reflective numbers are great because they are easier to see at night. Brown on black or white on yellow may look swanky but are bad choices for the purpose.
- Try not to put house numbers behind any trees, shrubs, or anything else that may obscure their view from the street.
- Make sure that the number faces the street that is listed in the house’s address. It does emergency workers no good if the house number faces a different street than the one the workers are traveling on.
- Is your house not visible from the road? Then the number should be placed at the driveway’s entrance.
- The next time you hire an InterNACHI inspector, ask him whether your numbers are adequate. Inspectors should know the laws in your area and be able to offer you a professional opinion.
Keep in mind that you may need to make adjustments.
Even if your house number is currently adequate, InterNACHI believes that it might need adjustment in the future. The following are common reasons why you may need to adjust your number in the future:
- The addresses assigned to houses by the city occasionally change, and you must adjust your numbers accordingly.
- The trees or shrubs in front of your house have grown so much that the number is no longer visible.
- House numbers installed in the winter may be visible during that season, but become blocked by budding vegetation by spring or summer.
Maintain your house numbers, along with the rest of your home’s exterior.
- Keep your numbers clean. They may not be reflective or contrasting if they are covered in mud.
- Trim back vegetation as needed.
- Don’t let piles of snow obscure the numbers. If this happens, raise the number so this situation does not happen again.
Winterization is the process of preparing a home for the harsh conditions of winter. It is usually performed in the fall before snow and excessive cold have arrived. Winterization protects against damage due to bursting water pipes, and from heat loss due to openings in the building envelope. Inspectors should know how winterization works and be able to pass this information on to their clients
Water damage caused by bursting pipes during cold weather can be devastating. A ruptured pipe will release water and not stop until someone shuts off the water. If no one is home to do this, an enormous quantity of water can flood a house and cause thousands of dollars’ worth of damage. Even during very small ruptures or ruptures that are stopped quickly, water leakage can result in mold and property damage. Broken water pipes can be costly to repair.
- All exposed water pipes in cold areas, such as attics, garages, and crawlspaces, should be insulated. Foam or fiberglass insulation can be purchased at most hardware stores. Insulation should cover the entirety of a pipe.
- Plastic is more tolerant of cold expansion than copper or steel. Houses in colder climates might benefit from the exclusive use of approved plastic plumbing.
- Water supply for exterior pipes should be shut off from inside the house and then drained.
- Sprinkler systems are particularly vulnerable to cracking due to cold-weather expansion. In addition to turning them, it helps to purge the system of any remaining water with compressed air.
- Homeowners should be aware that much of the plumbing system travels through areas that are significantly colder than the rest of the house. Because it is impossible to monitor the temperature of every portion of the plumbing system, indoor air temperature should be kept high enough throughout the winter to keep pipes in any unheated places from freezing.
Leaks in the Building Envelope
- Windows that leak will allow cold air into the home. Feeling for drafts with a hand or watching for horizontal smoke from an incense stick are a few easy ways to inspect for leaks. They can be repaired with tape or caulk.
- On a breezy day, a homeowner can walk through the house and find far more leaks than they knew existed. Leaks are most likely in areas where a seam exists between two or more building materials.
- Because hot air rises into the attic, a disproportionately larger amount of heat is lost there than in other parts of the house. Like a winter hat that keeps a head warm, adequate attic insulation will prevent warm indoor air from escaping. Attic insulation should be 12 inches thick in cold climates.
- Storm doors and windows should be installed to insulate the house and protect against bad weather.
- Test the furnace by raising the temperature on the thermostat. If it does not respond to the adjustment quickly it might be broken.
- Replace the air filter if it’s dirty.
- If the furnace is equipped with an oil or propane tank, the tank should be full.
- Use a hose to remove leaves and other debris from the outdoor condensing unit, if the home is equipped with one. Protect the unit with a breathable waterproof cover to prevent rusting and freezing of its components.
- Remove and store window air conditioners when they are no longer needed. Cold air can damage their components and enter the house through openings between the air conditioner and the windowpane.
- Ceiling fans can be reversed in order to warm air trapped beneath the ceiling to recirculate. A fan has been reversed if it spins clockwise.
- The chimney should be inspected for nesting animals trying to escape the cold. Squirrels and raccoons have been known to enter chimneys for this reason.
- The damper should open and close with ease. Smoke should rise up the chimney when the damper is open. If it doesn’t, this means that there is an obstruction in the chimney that must be cleared before the fireplace can be used.
- A chimney-cleaning service professional should clean the chimney if it has not been cleaned for several years.
- The damper should be closed when the fireplace is not in use. An open damper might not be as obvious to the homeowner as an open window, but it can allow a significant amount of warm air to escape.
- Glass doors can be installed in fireplaces and wood stoves to provide an extra layer of insulation.
- If debris is left in gutters, it can get wet and freeze, permitting the formation of ice dams that prevent water from draining. This added weight has the potential to cause damage to gutters. Also, trapped water in the gutter can enter the house and lead to the growth of mold. For these reasons, leaves, pine needles, and all other debris must be cleared from gutters. This can be done by hand or with a hose.
- Missing shingles should be replaced.
- Patio furniture should be covered.
- If there is a deck, it might need an extra coat of sealer.
- Winterize toilets by emptying them completely. Antifreeze can be poured into toilets and other plumbing fixtures.
- Winterize faucets by opening them and leaving them open.
- Water tanks and pumps need to be drained completely.
- Drain all water from indoor and outdoor plumbing.
- Unplug all non-essential electrical appliances, especially the refrigerator. If no electrical appliances are needed, electricity can be shut off at the main breaker.
Ice dams are problematic because they force water to leak from the roof into the building envelope. This may lead to:
- rotted roof decking, exterior and interior walls, and framing;
- respiratory illnesses (allergies, asthma, etc.) caused by mold growth;
- reduced effectiveness of insulation. Wet insulation doesn’t work well, and chronically wet insulation will not decompress even when it dries. Without working insulation, even more heat will escape to the roof where more snow will melt, causing more ice dams which, in turn, will lead to leaks; and
- peeling paint. Water from the leak will infiltrate wall cavities and cause paint to peel and blister. This may happen long after the ice dam has melted and thus not appear directly related to the ice dam.
- Keep the entire roof cold. This can be accomplished by implementing the following measures:
- Install a metal roof. Ice formations may occur on metal roofs, but the design of the roof will not allow the melting water to penetrate the roof’s surface. Also,snow and ice are more likely to slide off of a smooth, metal surface than asphalt shingles.
- Seal all air leaks in the attic floor, such as those surrounding wire and plumbing penetrations, attic hatches, and ceiling light fixtures leading to the attic from the living space below.
- Increase the thickness of insulation on the attic floor, ductwork, and chimneys that pass through the attic.
- Move or elevate exhaust systems that terminate just above the roof, where they are likely to melt snow.
- A minimum of 3″ air space is recommended between the top of insulation and roof sheathing in sloped ceilings.
- Remove snow from the roof. This can be accomplished safely using a roof rake from the ground. Be careful not to harm roofing materials or to dislodge dangerous icicles.
- Create channels in the ice by hosing it with warm water. Because this process intentionally adds water to the roof, this should be done only in emergencies where a great deal of water is already flowing through the roof, and when temperatures are warm enough that the hose water can drain before it freezes.
Prevention and Removal Methods to Avoid
- electric heat cables. These rarely work, they require effort to install, they use electricity, and they can make shingles brittle.
- manual removal of the ice dam using shovels, hammers, ice picks, rakes, or whatever destructive items can be found in the shed. The roof can be easily damaged by these efforts, as can the homeowner, when they slip off of the icy roof.
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