Tuesday 27 March 2012

PVC - Things You May Not Know!

Polyvinyl chloride (PVC) is a widely used building material praised for its durability, yet criticized for its potential health hazards.

PVC was discovered accidentally in the early 19th century when the polymer appeared as a white solid inside sunlight-exposed flasks of vinyl chloride. The first attempt to use the substance commercially was made by Russian chemists who failed because of the PVC's rigidity and brittleness. In 1926, Waldo Semon, a rubber scientist for B.F. Goodrich, successfully plasticized PVC. It was put to use as insulation for electrical wiring. It became critical to the war effort during the 1940s, and its peacetime use subsequently exploded. Today, PVC is the third most relied-upon plastic in the world, after polyethylene and polypropylene.

As it is inexpensive, durable, strong, and chemically and biologically resistant, as well as easy to install and replace, PVC is widely used in the following construction applications:
insulation for electrical wires; frames for windows and doors, after impact-modifiers and stabilizers have been added; plumbing piping, especially sewage pipes and other applications where corrosion limits the use of metal. 

Roughly half of the world's PVC is used in municipal and industrial pipes. In the U.S., 66% of the water distribution pipes and 75% of sewage pipes are constructed from PVC. In addition, PVC pipes can be easily fused together to create permanent and virtually leak-free joints;
roofing and ceiling systems and membranes; and a multitude of other building components, such as flooring, carpet backing, wall coverings, junction boxes, shades and blinds, shower curtains, flues, gutters, downspouts, flashing and moldings.

Inspectors can be aided in the identification of PVC by its color, which often indicates its use: white PVC is used for drain and waste vent pipe and some low-pressure piping; dark gray is used for industrial pressure systems; purple is used for reclaimed wastewater; white, blue and dark gray are all used for cold-water pipe; and green is used for sewer lines.

Potential Hazards

While PVC is an extremely popular building material, its critics deride it for certain health and environmental dangers, especially when its entire life cycle is considered. Touted for its flame resistance, PVC can smolder unnoticed and release extremely dangerous gasses that present both acute and chronic health hazards to building occupants, fire fighters, and surrounding communities. The following two products of PVC combustion are of particular concern; hydrogen chloride, which is a corrosive, highly toxic gas that can burn skin and cause severe, permanent respiratory damage; and dioxin, the most dangerous known man-made carcinogen, which will persist in the environment for a long period of time. PVC is the largest contributor to the world’s dioxin burden.

PVC has also been blamed for emitting chemical softeners called phthalates (in vinyl flooring), lead additives (in blinds), and toxic glues. For instance, one study of PVC shower curtains found that they released phthalates capable of causing nausea and damage to the liver and reproductive system. Vinyl chloride, an essential component of PVC, is a carcinogenic and potentially explosive gas with a mild, sweet odor. It can enter drinking water released from contact with PVC pipes, according to the U.S. Environmental Protection Agency.

Disposal of PVC is problematic because its unique characteristics make ordinary disposal unsafe or otherwise difficult; it does not decompose when buried, and it releases dangerous gasses when incinerated. Much of the PVC used in buildings eventually winds up in landfills where it can easily smolder and release a significant amount of deadly gasses. Manufacturers counter this argument by pointing out that PVC's resilience makes it appear in landfills less than its alternatives, and that some landfill liners are actually composed of PVC.

Thermal depolymerization has been developed to convert used PVC into other usable materials, but this method is rarely employed. The multitude of additives used to create PVC make large-scale recycling so cumbersome and expensive that manufacturers find it more cost-effective to make new PVC. Only 0.5% of the plastic is actually recycled, according to the Healthy Building Network.

In summary, the qualities that make PVC an ideal and popular building material must be weighed against its potential health dangers. The health effects of PVC on humans and the environment is a contentious issue, and inspectors and homeowners can perform their own research to stay informed.

Low E Windows

Low-emissivity glass, also known as low-E glass, uses a microscopically thin and virtually invisible metal or metallic oxide layer incorporated in the glazing surface to control heat transfer through insulated windows, reducing energy loss by 30% to 50%. Since the heating and cooling energy lost through windows accounts for 4% of all U.S. energy consumption every year, the Department of Energy is beginning to push more efficient windows as a standard, with low-E windows at the forefront. Meanwhile, as more low-E windows are put into service, unexpected problems have arisen. Inspectors, who conduct energy audits, as well as energy-conscious consumers, can benefit from knowing more about these energy-efficient windows and the advantages and problems associated with them.
 
The super-thin coating utilized in low-E glass helps to reduce the transfer of heat through the window in order to keep heat from entering the home in hot climates, and to prevent heat from escaping from the home to the exterior in colder climates. The low-E coating is typically used on multi-pane windows with argon gas-fills. Argon is an inert gas which has higher resistance to heat flow than air, and is non-toxic, colorless and odorless. In hotter climates with east- or west-facing windows, the low-E coating is applied to the outer layer of the glazing to help keep the heat out. In colder, heating-dominated climates, it is applied to the inner layer to keep warmth in.
Installing low-E windows can provide significant energy efficiency and savings, especially in hotter climates where windows with a low solar heat-gain coefficient (SHGC) are most effective. The SHGC rating for a window is the quantification of its properties in relation to its ability to transmit heat from solar radiation. A high SHGC means more solar heat is allowed to pass through the window and a low SHGC means less solar heat will pass through. While a window with a higher SHGC can actually be beneficial in some climates where cooling needs are minimal, because it allows for more solar heat gain to warm the interior during winter months, windows with a low SHGC rating is best for hot climates where blocking the sun’s heat is much more important.

Saturday 17 March 2012

Inspecting your Air Conditioning System

A building's central air-conditioning system must be periodically inspected and maintained in order to function properly. While an annual inspection performed by a trained professional is recommended, homeowners can do a lot of the work themselves by following the tips offered in this guide.

Clean the Exterior Condenser Unit and Components

The exterior condenser unit is the large box located on the side of the building that is designed to push heat from the inside of the building to the outdoors. Inside of the box are coils of pipe that are surrounded by thousands of thin metal "fins" that allow the coils more surface area to exchange heat. Follow these tips when cleaning the exterior condenser unit and its inner components -- after turning off power to the unit!
  • Remove any leaves, spider webs and other debris from the unit's exterior. 
  • Trim foliage back several feet from the unit to ensure proper air flow. 
  • Remove the cover grille to clean any debris from the unit's interior. A garden hose can be helpful for this task.  
  • Straighten any bent fins with a tool called a fin comb. 
  • Add lubricating oil to the motor. 
  • Check your owner’s manual for specific instructions. 
  • Clean the evaporator coil and condenser coil at least once a year. When they collect dirt, they may not function properly. 

Inspect the Condensate Drain Line

Condensate drain lines collect condensed water and drain it away from the unit. They are located on the side of the inside fan unit. Sometimes there are two drain lines—a primary drain line that’s built into the unit, and a secondary drain line that can drain if the first line becomes blocked. Homeowners can inspect the drain line by using the following tips, which take very little time and require no specialized tools:
Inspect the drain line for obstructions, such as algae and debris. If the line becomes blocked, water will back up into the drain pan and overflow, potentially causing a safety hazard or water damage to your home.
Make sure the hoses are secured and fit properly.

Clean the Air Filter

Air filters remove pollen, dust and other particles that would otherwise circulate indoors. Most filters are typically rectangular in shape and about 20 inches by 16 inches, and about 1 inch thick. They slide into the main ductwork near the inside fan unit. The filter should be periodically washed or replaced, depending on the manufacturer’s instructions. A dirty air filter will not only degrade indoor air quality, but it will also strain the motor to work harder to move air through it, increasing energy costs and reducing energy efficiency. The filter should be replaced monthly during heavy use during the cooling seasons. You may need to change the filter more often if the air conditioner is in constant use, if building occupants have respiratory problems,if you have pets with fur, or if dusty conditions are present.

Cover the Exterior Unit

When the cooling season is over, you should cover the exterior condenser unit in preparation for winter. If it isn’t being used, why expose it to the elements? This measure will prevent ice, leaves and dirt from entering the unit, which can harm components and require additional maintenance in the spring. A cover can be purchased, or you can make one yourself by taping together plastic trash bags. Be sure to turn the unit off before covering it.

Close the Air-Distribution Registers

Air-distribution registers are duct openings in ceilings, walls and floors where cold air enters the room. They should be closed after the cooling season ends in order to keep warm air from back-flowing out of the room during the warming season. Pests and dust will also be unable to enter the ducts during the winter if the registers are closed. These vents typically can be opened or closed with an adjacent lever or wheel. Remember to open the registers in the spring before the cooling season starts. Also, make sure they are not blocked by drapes, carpeting or furniture.

In addition, homeowners should practice the following strategies in order to keep their central air conditioning systems running properly:
  • Have the air-conditioning system inspected by a professional each year before the start of the cooling season. 
  • Reduce stress on the air conditioning system by enhancing your home’s energy efficiency. Switch from incandescent lights to compact fluorescent, for instance, which produce less heat. 

In summary, any homeowner can perform periodic inspections and maintenance to their home's central air-conditioning system.

Wednesday 7 March 2012

Efflorescence

Efflorescence is an accumulation of minerals and salts on masonry surfaces, such as brick, cement, and sometimes stone. Efflorescence itself is not dangerous; it indicates the presence of excess water, which can lead to more serious structural and health issues.


How Efflorescence Forms

The earth contains natural salts that are present in the raw materials that make up masonry products, such as concrete, asphalt and stucco. These salts remain trapped within masonry in solid form until they are dissolved into water, which usually makes its way into the material through small pores. Water can originate from rain, sprinklers, household leaks, or any number of other places. Cold, dry air will draw this liquid back out of the material where it evaporates, depositing the salt as a white crystalline growth on the surface. Efflorescence typically forms during cold, dry weather shortly after it has rained and moisture has entered the masonry. It can occur year-round, but it is most likely to form during the winter due to low temperatures.

As with mould, the appearance of efflorescence varies greatly. It can be powdery, it can have sharp edges and be easy to spot, or it can have indistinct edges. It can cover a large area as a fine dust, or form large individual crystals. Its appearance depends partly on the type of salt from which it is composed, but humidity also plays a role in this determination. In exceptionally dry climates, water can evaporate before it even reaches the surface, in which case the salt will accumulate unseen beneath the surface. In humid conditions, moisture may take a long time to evaporate, allowing the slow growth of “whispers” projecting from the surface.



Inspectors should note the presence of efflorescence in their inspection reports because it generally occurs where there is excess moisture, a condition that also encourages the growth of mould. An exception can be made during the first few years of a building’s construction when efflorescence will appear as a result of moisture locked within the masonry in a process called “new building bloom.” This moisture comes from water added during the manufacturing or mixing process that will undoubtedly contribute to efflorescence. This type of efflorescence will appear all over the masonry material and will continue to accumulate until the initial water supply is exhausted, which can take up to a year. Efflorescence that appears locally and after the “new building bloom” is over is a symptom of excess moisture that can be problematic. The source of this moisture should be determined and corrected.

In summary, efflorescence is a harmless yet unsightly accumulation of salts on masonry surfaces. Its presence indicates excess water, a condition that can damage interiors and encourage the growth of mould. Inspectors should know how to remove efflorescence from surfaces, and educate their clients about its identification and significance.

Saturday 3 March 2012

Pre-Listing Home Inspections

Home inspections have traditionally been for the benefit of the purchaser. Pre-inspected listings benefit all parties - purchasers, vendors and Realtors.

Home inspections, performed as a condition of the offer, can kill deals. Sometimes this is because the purchaser gets cold feet; sometimes there's a big problem no one knew about. Sometimes it is because the house has been misrepresented; sometimes it is because the home inspector scared the purchasers by not explaining that minor and typical problems are just that - minor and typical.

If the home inspection is performed prior to the house being listed, all parties will be aware of the physical condition of the house before an offer is drawn. There will be no surprises after the fact. Deals will not fall through.

Pre-inspected Listings Avoid Renegotiation

In a buyers' market, most houses have to be sold twice. It takes a lot of work to get a signed Agreement of Purchase and Sale. Then the home inspection is done and the purchaser wants to renegotiate.

If all parties know the condition of the house prior to the offer, there is no need for renegotiation. As most real estate agents know, renegotiation is very difficult. Vendors have already mentally sold the house; purchasers are suffering buyers' remorse. Egos, pride and frustration can muddy the already emotional waters.

A vendor who pays for a home inspection will be further ahead than one who has to renegotiate.

Unrealistic Vendors

An inspection at the time of listing can also help a Realtor deal with a vendor who has unrealistic expectations. The inspection report is good ammunition for explaining why you can't ask top bucks for a house which is not in top condition.

Repairs Prior To Sale

Sometimes, the home inspection will reveal items which should be repaired immediately. A pre-inspected listing allows the vendor to repair the problem prior to putting the house on the market.

If the inspection occurs after the Agreement of Purchase and Sale, the purchaser could walk, renegotiate or, depending on the inspection clause, the vendor may have the option to repair. A repair done by an unmotivated vendor may not be the best repair and may not meet the purchasers' expectations. This has caused more than one deal not to close.

Peace of Mind for the Purchaser

There is no doubt that part of the value of a home inspection is a guided tour of the house for the prospective purchaser. We can always return to do a walk-through with the purchaser, if requested.