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How to Control Dandelions

What makes dandelion removal from lawns so difficult? Well, enjoy the best of both worlds. Above-ground, their seeds ride the wind currents, poised to drop into the slightest opening in your lawn to propagate the species. Meanwhile, below-ground, dandelions strike down a taproot up to 10" long. Pulling the taproot as a means of dandelion removal is problematic. Thick but brittle, the taproot easily fractures - and any fraction of the taproot that remains in the ground will regenerate.

How to Kill Dandelions: Pulling Them

If you're hard-headed enough to want to try to pull dandelions, despite the difficulty just mentioned, here's how to proceed:

• To facilitate weeding, water the lawn first (weeds are more easily extricated from wet soil).
• Make an incision into the soil, down along the side of the dandelion taproot, using a knife, screwdriver or similar tool (tools designed specifically for dandelion removal can be found in home improvement stores).
• Wiggle the tool to loosen the dandelion taproot
• Using the ground as a fulcrum, try to pry up the dandelion weed.
• Get a good grip on the dandelion leaves (as many of them as you can close your hand over) and use them as your "handle" on which to tug.
• Give the dandelion weed a gentle tug to see if the taproot is yielding.
• If the taproot is yielding, remove the dandelion weed from the soil. Otherwise, make further incisions around the taproot, wiggle and continue to tug gently at the dandelion leaves.

Preventive Dandelion Control

Promoting lawn health is the best method of dandelion control. Don't think of your lawn grass as a passive partner, which has to be rescued from dandelions after the fact. If managed properly, your lawn can compete effectively against dandelions and other weeds, alleviating the need for laborious dandelion removal.

Follow these lawn-care tips:

Leave grass clippings on your lawn. They will act as a mulch to prevent weed seeds from germinating. The benefits of grass clippings to your lawn, under the right conditions, are numerous.

Mow "high", leaving the lawn grass at a height of 2 1/2"-3". This will allow the lawn grass to "protect its own turf" better, depriving dandelions of the light they need.

Don't let bare spots remain uncovered for long; else you're just inviting the invasion of opportunistic dandelions. In the fall, fill in those bare spots by over seeding.

Plastic - Impact on Oceans and Beaches

"The success of the plastic bag has meant a dramatic increase in the amount of sacks found floating in the oceans where they choke, strangle, and starve wildlife and raft alien species around the world.

Plastic bags have gone "from being rare in the late 80s and early 90s to being almost everywhere from Spitsbergen 78° North [latitude] to Falklands 51° South [latitude], but they will probably be washing up in Antarctica within the decade."

Furthermore:

• Plastic bags are among the 12 items of debris found most often in coastal cleanups, according to the Center for Marine Conservation
• Plastic bags wrap around living corals quickly "suffocating" and killing them according to the US National Oceanic and Atmospheric Administration

The very thing that makes plastic items useful to consumers, their durability and stability, also makes them a problem in marine environments. Around 100 million tonnes of plastic are produced each year of which about 10 percent ends up in the sea. About 20 percent of this is from ships and platforms, the rest from land.

Take a walk along any beach anywhere in the world and washed ashore will be many polythene plastic bags, bottles and containers, plastic drums, expanded polystyrene packing, polyurethane foam pieces, pieces of polypropylene fishing net and discarded lengths of rope. Together with traffic cones, disposable lighters, vehicle tyres and toothbrushes, these items have been casually thrown away on land and at sea and have been carried ashore by wind and tide.

These larger items are the visible signs of a much larger problem. These big items do not degrade like natural materials. At sea and on shore under the influence of sunlight, wave action and mechanical abrasion they simply break down slowly into ever smaller particles.

A single one litre drinks bottle could break down into enough small fragments to put one on every mile of beach in the entire world. These smaller particles are joined by the small pellets of plastic which are the form in which many new plastics are marketed and which can be lost at sea by the drum load or even a whole container load. These modern day “marine tumbleweeds” have been thrown into sharp focus, not only by the huge quantities removed from beaches by dedicated volunteers, but by the fact that they have been found to accumulate in sea areas where winds and currents are weak.

Bags and small plastic pieces can entangle marine animals causing them to drown. They can also be swallowed by marine animals like whales and turtles, causing them to starve….

Wildlife in the oceans is increasingly falling victim to human waste, with virtually all dead sea-birds found to have eaten litter carried in the water, according to a new study.

Scientists measuring the amount of waste found in fulmars discovered that 96 per cent of the birds had fragments of plastic in their stomachs. The figure was almost double the amount discovered in the early 1980s

The issue of plastic debris is one that needs to be urgently addressed. At the personal level we can all contribute by avoiding plastics in the things we buy and by disposing of our waste responsibly. Obviously though, there is a need to make ship owners and operators, offshore platforms and fishing boat operators more aware of the consequences of irresponsible disposal of plastic items.

Compact Fluorescent Light Bulbs

If every North American home replaced just one light bulb with an ENERGY STAR qualified bulb, we would save enough energy to light more than 3 million homes for a year, more than $600 million in annual energy costs, and prevent greenhouse gases equivalent to the emissions of more than 800,000 cars.

• Qualified bulbs use about 75 percent less energy than standard incandescent bulbs and last up to 10 times longer.
• Save about $30 or more in electricity costs over each bulb's lifetime.
• Produce about 75 percent less heat, safer to operate and can cut energy costs.
• Are available in different sizes and shapes, for indoors and outdoors.

How to Choose and Where to Use CFL’s:

ENERGY STAR qualified CFL’s provide the greatest savings in fixtures that are on for a substantial amount of time each day. At a minimum, ENERGY STAR recommends installing qualified CFL’s in fixtures that are used at least 15 minutes at a time or several hours per day. The best fixtures to use qualified CFL’s in are usually found in the following areas of your home:

• family and living rooms
• kitchen
• dining room
• bedrooms
• outdoors

How to Choose the Right Light:

Matching the right CFL to the right kind of fixture helps ensure that it will perform properly and last a long time.

• CFL’s perform best in open fixtures that allow airflow, such as table and floor lamps, wall sconces, pendants, and outdoor fixtures.
• For recessed fixtures, it is better to use a reflector CFL than a spiral CFL since the design of the reflector evenly distributes the light down to your task area.
• If a light fixture is connected to a dimmer or three-way socket fixture, you'll need to use a special ENERGY STAR qualified CFL designed to work in these applications. Make sure to look for CFL’s that specify use with dimmers or three-way fixtures.
• Choose a qualified CFL that offers a shade of white or soft white light for your home, you could choose a cooler color for task lighting.
• To choose the ENERGY STAR qualified CFL with the right amount of light, find a qualified CFL that is labelled as equivalent to the incandescent bulb you are replacing. Light bulb manufacturers include this information right on the product packaging to make it easy for consumers to choose the equivalent bulb. Common terms include "Soft White 60" or "60 Watt Replacement."

You should also check the lumen rating to find the right CFL. The higher the lumen rating, the greater the light output. Consult the following chart to determine what CFL wattage is best to replace your incandescent light bulb:

Incandescent light bulbs	Minimum light output	Compact Fluorescents
Watts	Lumens	Watts
40	450	9-13
60	800	13-15
75	1100	18-25
100	1600	23-30
150	2600	30-52

Organic Choice In Weed Killers?

Artificial weed killers are a quick and nasty way to deal with garden weeds. Mix and spray chemical herbicide is a simple "no brainer" solution. An inappropriate import from agriculture direct to the domestic garden scene.

The talk is about protecting children, pets etc... but it is the gardener who mixes and sprays chemical herbicides who is most at risk. Also pond life - frogs, newts etc... are especially susceptible to the ill effects of artificial herbicides.

Sometimes however, there are intractable problems (e.g. weeds among other plants, rock gardens, physical disability, expedience...) that do favour alternative solutions.

Let's look at what does work in organic gardening.

Natural Weed Killers

These are simple substances with a direct and obvious action. They destroy plant life for a short period. They are substances encountered naturally but in small quantities. Their presence is well-known and normally not harmful. But when applied in big doses the results are usually devastatingly obvious in a very short time. Examples include salt, weak organic acids, alcohol, heat from steam, boiling water, and weed flamers.

As always these methods need due caution. But they act at the point they are used and don't enter the food chain. After treatment their damaging effect quickly dissipates. Even the treated plants may sometimes recover.

Acetic Acid Weed Killers

It is made of Acetic Acid (Vinegar) along with other weak organic acids and oils. It has become a 'cottage garden' alternative for those who dislike modern herbicides. Acid is a very blunt instrument, changing the chemistry around roots and in cell sap, to affect the plant in many ways. The damage to plants appears rapidly and even quicker on hot days.

Household Vinegar at 5% acetic acid is not strong enough; 15-20% acetic acid solutions are more effective. Avoid industrial vinegars in the organic garden.

Studies have found acetic acid gave over 90% control within 24 hours of application. With 3 treatments of 20% acetic acid, control remained above 90% even after 9 weeks.

The soil can be acidified but this type of weak organic acid lasts only a few days. That's not long enough to have any lasting affect on earthworms, soil, or organic matter breakdown. The good news is that it won’t cause any insidious harm to pets or children.

Garden products based on acetic acid are now available for organic gardeners as alternative herbicides. It can kill Canadian Thistle, Clover, Dandelion, Foxtail, Ivy Leaf, Milkweed, Pigweed, Poison Hemlock, Ragweed, Quack grass, Bluegrass, plus mosses, liverworts and more. It is not selective and harms the plants it touches.

Fatty Acid Weed Killers

These work by dissolving the plant membranes, making them leaky. The plants dehydrate. Of the 2 products, fatty acids have the edge. They are less broadly harmful, that their soapy properties aid uptake and reduce spreading in the soil.

Obviously you must avoid spraying these on cultivated plants. So it’s probably best confined to spot treatments, perhaps when you need extra help with weed control and to avoid the seriously nasty herbicides.

Remember, if you burn a hole in the lawn with these treatments it is important to fill the empty space as soon as possible. Sow seed and promote strong thick re-growth with the help of organic fertilizers. If your lawn becomes patchy it will become weedier. Always prevent weed seeds being distributed.

Salt Weed Killers

Salt draws water out of cells to leave them dry, and salty soils kill plant roots. So target its application and use sparingly.

Excess salt poisons the soil. Many important organisms: bacteria, fungi, earthworms; will be killed by salinity. It will eventually wash out, even so I would not use it on land intended for cultivating plants. For some gardeners it is an option to consider with drives and gravel areas where plants are not intended to grow and where run off can be contained. Remember, salt will not biodegrade, so regular use will eventually be detrimental to surrounding areas.

Reusable Shopping Bags

Billions of plastic bags are choking our planet. All of these "free" bags ultimately cost both consumers and the environment plenty:

• Each year, 500 billion to 1 trillion plastic bags are consumed worldwide
• In the USA over 380 billion plastic bags, sacks, wraps are consumed each year.
• Australians consume 6.9 billion plastic bags each year - 326 per person.

What better ways to attack the problem than with bring from home, reusable bags. Reusable bags are the latest accessory for the well-dressed, eco-minded shopper. These alternatives to plastic grocery bags have been selling out in supermarkets across the nation. Not that consumers are painting the town green yet – they keep forgetting to bring their new bags to the stores.

Reusable shopping bags come in various sizes, materials and designs. But how much a bag can hold is not as important as how much you can hold. (The latter is usually less than the former, especially when lugging several bags.) Good looks never hurt, either. You don't have be a walking advertisement for the store you bought your bag at. And you don't have to stick to the supermarket offerings.

Plastic Bags – What’s the big Deal

Billions of plastic bags are choking our planet.

• All of these "free" bags ultimately cost both consumers and the environment plenty:
• Each year billions of bags end up as ugly litter.
• Eventually they break down into tiny toxic bits polluting our soil, river, lakes and oceans
• Production requires vast amounts of oil.
• Countless animals needlessly die each year.

Ontario shoppers use an estimated 7 million plastic grocery bags a day. The province is determined to cut that in half within five years, and has partnered with big supermarket chains and the Recycling Council of Ontario to figure out exactly how.

Around the world, the war on plastic bags is being fought on several fronts. Last month, Leaf Rapids, Man., became the first Canadian community to ban plastic bags – following the lead of San Francisco, which has banned plastic bags in grocery stores and large drugstores. Back in 2002, Ireland decided to charge for plastic bags, to fight a "plague" of litter.

Top Facts - Consumption

• Each year, an estimated 500 billion to 1 trillion plastic bags are consumed worldwide. That comes out to over one million per minute. Billions end up as litter each year.
• According to the EPA, over 380 billion plastic bags, sacks, wraps are consumed each year.
• According to The Wall Street Journal, the U.S. goes through 100 billion plastic shopping bags annually. (Estimated cost to retailers is $4 billion)
• According to the industry publication Modern Plastics, Taiwan consumes 20 billion bags a year—900 per person.
• According to Australia’s Department of Environment, Australians consume 6.9 billion plastic bags each year - 326 per person, 7% or 49.6 million end up as litter each year.
  
  

Top Facts - Environmental Impact

• Hundreds of thousands of sea turtles, whales and other marine mammals die every year from eating discarded plastic bags mistaken for food.
• Plastic bags don’t biodegrade, they photodegrade—breaking down into smaller and smaller toxic bits contaminating soil and waterways and entering the food web when animals accidentally ingest.
• As part of Clean Up Australia Day, nearly 500,000 plastic bags were collected.
• Windblown plastic bags are so prevalent in Africa that a cottage industry has sprung up harvesting bags and using them to weave hats, and even bags.
• According to David Barnes, a marine scientist with the British Antarctic Survey, plastic bags have gone "from being rare in the late 80s and early 90s to being almost everywhere from Spitsbergen 78° North [latitude] to Falklands 51° South latitude.
• Plastic bags are among the 12 items of debris most often found in coastal cleanups, according to the non-profit Center for Marine Conservation.

Factors that compromise insulation

Moisture

With an airtight building, consideration also must be made to appropriate ventilation and moisture control. Excessive humidity and/or condensation can be significant issues. Excessive moisture (or invisible humidity) can rot construction materials and/or encourage microbial growth eg. mold, bacteria. Moisture can also drastically reduce the effectiveness of insulation by creating a thermal bridge. Damp materials may lose most of their insulating properties. The choice of insulation often depends on the means used to manage moisture and condensation on one side or the other of the thermal insulator.

Thermal bridge

Thermal bridges are points in the building envelope that allow heat conduction to occur. Since heat flows through the path of least resistance, thermal bridges can contribute to poor energy performance. A thermal bridge is created when materials that are poor insulators come into contact. Wood and rubber are poor insulators - thus heat can flow through joists and studs.

Poor construction technique can create thermal bridges or areas which are inaccessible to further insulation. When bulk insulation becomes wet it acts as conductor rather than an insulator of heat, and can therefore also form a thermal bridge. Incorporating inaccessible voids within the wall cavity which do not allow the interposition of insulation can be another source of thermal bridging.

Insulation around a bridge is of little help in preventing heat loss or gain due to thermal bridging. The bridging has to be rebuilt with smaller or more insulative materials. A common example of this is an insulated wall which has a layer of rigid insulating material between the studs and the finish layer.

Insulation 101

Understanding Heat Transfers and Insulation

Energy efficiency of any structure is defined by its ability to control the three basic types of heat flow. These modes of heat transfer vary in importance and magnitude for any structure depending upon the materials used and workmanship employed to construct the building 'envelope'.

Basically heat is transferred in three ways:

Conduction is the transfer of heat through solid portions of a structure. The transfer of heat conduction can be significantly reduced by using insulation. Insulation is a material with low thermal conductivity which thereby resists the flow of heat. This thermal resistance or R-value is a uni-directional measurement of this type of heat flow. The higher the R value, the greater the insulating value.

Convection as it relates to a building structure is the transfer of heat through the movement of air induced by pressure differentials. This can occur due to temperature or humidity differences, wind or mechanical air movement. The term air infiltration, or air leakage, refers to air that enters the structure through gaps and cracks in the building envelope.

Radiation is the transfer of heat by light waves that generate heat upon contact with any material capable of converting the radiation to heat and then releasing this heat as radiation to the air or conducting the heat to adjacent material. Radiation impeding materials, or 'radiant barriers', such as aluminum foil block the radiation light waves and greatly reduce the heat generation.

In Canada, 'radiant barriers' are often used as external facings of rigid board insulations and sometimes in residential attics. Why? As a facer for rigid insulations used as sheathing for the building envelope it acts somewhat as a radiant barrier, primarily to eliminate the reduction of R-value due to aging that all cellular plastic insulations experience.

In attics, when sunlight strikes a roof, the attic space heats up considerably. A radiant barrier installed in the attic absorbs the heat and releases the radiant heat waves back into the attic space as apposed to transmitting the heat into the living space.

Unfortunately, there is still heat buildup in the attic from the hot roofing materials and other structural components that transfer heat through conduction. This means that high levels of thermally resistive (by conduction) insulation such as fiberglass batts or loosefill insulation are required to impede the conduction of heat into the living area. In Canada, radiant barriers are not effective as solar heat gain to warm the attic in the winter months is desired.

Conduction - Install loose fill insulation or fiberglass batts in the attic, fiberglass batts or spray applied polyurethane foams in the walls and fiberglass batts or polyurethane foams in the floors.

Air leakage - Use foam insulations or sealants to seal the holes, crevices and penetrations in the exterior framing envelope of the house. Also install sprayed-in-place polyurethane foam air barriers for commercial and industrial applications.

Radiation - Most insulations which that is installed should have a cellular structure which blocks the flow of heat of radiation. If the cavity is completely filled with insulation, the radiant heat loss from the inside finish to the outside sheathing is virtually eliminated.

Recommended Insulation Levels

Since insulation levels vary for commercial and institutional buildings as specified by the design professional we will present insulation levels as they relate to residential construction. When deciding on insulation levels, the house should be viewed as a whole, for example it makes very little sense to add a high level of insulation in the attic when the exterior walls have low insulation values, or the basement is uninsulated. Since heat loss occurs through all areas of a house, each part of the building envelope which separates the heated interior from the outside needs to be insulated.

The list below gives recommended levels of insulation. Values are shown in both imperial 'R' and metric ('RSI') units.

Minimum Recommended Insulation Levels:

	Traditional Space Heating	Electric Space Heating
Basement Floors	R-8 (RSI-1.41)	R-8 (RSI-1.41)
Basement Walls	R-10 (RSI-1.8)	R-19 (RSI-1.8)
Above Grade Walls	R-17 (RSI-3.0)	R-27 (RSI-4.75)
Ceiling	R-31 (RSI-5.4)	R-40 (RSI-7.04)
Floors Over Unheated Spaces	R-25 (RSI-4.4)	R-25 (RSI-4.4)
Exposed Cantilevers	R-25 (RSI-4.4)	R-25 (RSI-4.4)
Cathedral Ceiling	R-20 (RSI-3.52)	R-22 (RSI-3.87)

Note: R-1 = 0.1761 RSI

Sealing Air flow

Air sealing is important, not only because drafts are uncomfortable, but also because air leaks carry both moisture and energy, usually in the direction you don't want. For example, air leaks can carry hot humid outdoor air into your house in the summer, or can carry warm moist air from a bathroom into the attic in the winter.

Most homeowners are aware that air leaks into and out of their houses through small openings around doors and window frames and through fireplaces and chimneys. Air also enters the living space from other unheated parts of the house, such as attics, basements, or crawlspaces.

The air travels through:

• any openings or cracks where two walls meet, where the wall meets the ceiling, or near interior door frames;
• gaps around electrical outlets, switch boxes, and recessed fixtures;
• gaps behind recessed cabinets, and furred or false ceilings such as kitchen or bathroom soffits;
• gaps around attic access hatches and pull-down stairs;
• behind bath tubs and shower stall units;
• through floor cavities of finished attics adjacent to unconditioned attic spaces;
• utility chase ways for ducts, etc., and plumbing and electrical wiring penetrations.

These leaks between the living space and other parts of the house are often much greater than the obvious leaks around windows and doors. Since many of these leakage paths are driven by the tendency for warm air to rise and cool air to fall, the attic is often the best place to stop them. It's important to stop these leaks before adding attic insulation because the insulation may hide them and make them less accessible. Usually, the attic insulation itself will not stop these leaks and you won't save as much as you expect because of the air flowing through or around the insulation.

Air-Barrier Materials

Requirements for Air-Barrier Systems

The air-barrier system is an important part of any retrofit job. It is the main means of protecting the building structure and the insulation from moisture damage. In order to be effective, the air-barrier system must be:

• resistant to air movement
• continuous, completely surrounding the envelope of the house and properly supported by rigid surfaces on both the interior and exterior (to prevent movement in high winds)
• strong and durable

A variety of materials are used throughout the envelope to act as the air barrier. In some cases, building materials such as drywall, baseboards or structural members are incorporated into the air barrier by sealing them to adjoining materials.

Air-Barrier System Components

The most common components of an air-barrier system are:

• sheet or rigid materials for large surfaces
• caulking and gaskets for joints between materials that do not move
• weather stripping for joints that do move

Choosing Air-Barrier Materials

If the material offers resistance to airflow, strength and durability, consider the following installation factors:

• Is it easy to install?
• If installed in a concealed location, will it last the life of the building or will it be accessible and easily repaired?
• Is it compatible with other materials in the system? Can it be successfully sealed to adjacent materials?
• Is the choice of material appropriate for the other work being done on the home? Some renovation work will permit the installation of a new sheet-material air barrier, while other jobs may require comprehensive air-sealing work instead.
• Does it serve other functions such as acting as insulation or as a vapour barrier?

Sheet Materials

Polyethylene Sheeting

• Available in wide sheets, minimizing the number of seams required.
• Seams and edges should be supported on both sides to maintain the seal.
• A thickness of 0.15 mm (6 mil) now commonly installed as an air barrier.
• Should be protected from exposure to sunlight. When exposed to sunlight over extended periods, a UV-stabilized polyethylene should be used.
• Should be clear, made from virgin material and labelled. Should conform to the Canadian General Standards Board standard for polyethylene.
• Can also function as a vapour barrier.

Housewrap

• Available in wide sheets, minimizing the number of seams required.
• Acts solely as an air barrier; does not function as a vapour barrier.
• Used to wrap the exterior of a house; often bonded to exterior glass-fibre sheathing.
• When installed on the exterior, acts as a wind barrier, preventing wind from reducing the effective RSI value of insulation.
• Should be protected from extended exposure to sunlight.

Rigid Materials

Most solid building components will act as barriers to air. These components include drywall, plaster, plywood, glass, wood and poured concrete (not concrete blocks). Insulating materials such as rigid foam boards also act as air barriers. To be effective, the seams between these various materials must be sealed with caulking, weatherstripping or gasket.

• For example, caulking can be used between the baseboard and a wall as well as between the baseboard and the floor, linking the air-sealing qualities of three different building components.

Green Roofs

Green Roofs

A green roof is a roof of a building that is partially or completely covered with vegetation and soil, or a growing medium, planted over a waterproofing membrane. It may also include additional layers such as a root barrier and drainage and irrigation systems. Container gardens on roofs, where plants are maintained in pots, are not generally considered to be true green roofs. The term "green roof" may also be used to indicate roofs that utilize some form of "green" technology, such as solar panels or a photovoltaic module. Green roofs are also referred to as eco-roofs, vegetated roofs, living roofs, and green roofs.

Benefits of green roofs

• Provide amenity space for building users — in effect replacing a yard or patio.
• Grow fruits, vegetables, and flowers
• Reduce heating (by adding mass and thermal resistance value) and cooling (by evaporative cooling) loads.
• Reduce the urban heat island effect.
• Increase roof life span.
• Reduce storm water run off.
• Filter pollutants and CO2 out of the air
• Filter pollutants and heavy metals out of rainwater.
• Increase wildlife habitat in built-up areas.

History and uses of green roofs

Modern green roofs, which are made of a system of manufactured layers deliberately placed over roofs to support growing medium and vegetation, are a relatively new phenomenon. They were developed in Germany in the 1960s, and have since spread to many countries. Green roofs are also becoming increasingly popular in the United States, although they are not as common as in Europe.

Many green roofs are installed to comply with local regulations and government fees, often regarding storm water runoff management. In areas with combined sewer-storm water systems, heavy storms can overload the wastewater system and cause it to flood, dumping raw sewage into the local waterways.

Green roofs decrease the total amount of runoff and slow the rate of runoff from the roof. It has been found that they can retain up to 75% of rainwater, gradually releasing it back into the atmosphere via condensation and transpiration, while retaining pollutants in their soil.

Combating the urban heat island effect is another reason for creating a green roof. Traditional building materials soak up the sun's radiation and re-emit it as heat, making cities at least 4 degrees Celsius (7 °F) hotter than surrounding areas. Roof temperatures on a hot day are typically 14–44 degrees Celsius (25–80°F) cooler than they are on traditionally roofed buildings nearby. It has been estimated that if all the roofs in a major city were "greened," urban temperatures could be reduced by as much as 7 degrees Celsius.

Green roofs have also been found to dramatically improve a roof’s insulation value. A study conducted by Environment Canada found a 26% reduction in summer cooling needs and a 26% reduction in winter heat losses when a green roof is used. In addition, greening a roof is expected to lengthen a roof’s lifespan by two or three times.

Finally, green roofs provide habitat for plants, insects, and animals that otherwise have limited natural space in cities. Even in high-rise urban settings, it has been found that green roofs can attract beneficial insects, birds, bees and butterflies. Rooftop greenery complements wild areas for songbirds, migratory birds and other wildlife facing shortages of natural habitat.

Types of green roof

Green roofs can be categorized as "intensive", "semi-intensive" or "extensive", depending on the depth of planting medium and the amount of maintenance they need. Traditional roof gardens, which require a reasonable depth of soil to grow large plants or conventional lawns, are considered "intensive" because they are labour-intensive, requiring irrigation, feeding and other maintenance. "Extensive" green roofs, by contrast, are designed to be virtually self-sustaining and should require only a minimum of maintenance, perhaps a once-yearly weeding or an application of slow-release fertilizer to boost growth.

Costs of green roofs

A properly designed and installed Green Roof system can cost 5 (in Europe) to 35 dollars per square foot The cost depends on what kind of roof it is, the structure of the building, and what plants can grow on the material that is on top of the roof.

Some cost can also be attributed to maintenance. Extensive green roofs have low maintenance requirements but they are generally not maintenance free. Maintenance of green roofs often includes fertilization to increase flowering and succulent plant cover. If aesthetics is not an issue, fertilization and maintenance is generally not needed. Extensive green roofs should only be fertilized with controlled release fertilizers in order to avoid pollution of the storm water. Conventional fertilizers should never be used on extensive vegetated roofs.

What is R Value ?

A material’s R-value is the measure of its resistance to heat flow. The way it works is simple: the higher the R-value, the more effective it is, the more the material insulates. The R-value of thermal insulation depends on the type of material, its thickness, and its density. In calculating the R-value of a multi-layered installation, the R-values of the individual layers are added. It is important to know the R-value because many provinces, states or regions require that a roof system have a minimum amount of thermal resistance on commercial, industrial, and/or institutional buildings. House Insulation should be purchased based on its R value, not thickness or weight.

The effectiveness of an insulated ceiling, wall or floor depends on how and where the insulation is installed.

• Insulation which is compressed will not give its full rated R-value. This can happen if you add denser insulation on top of lighter insulation in an attic. It also happens if you place batts rated for one thickness into a thinner cavity, such as placing R-19 insulation rated for 6 1/4 inches into a 5 1/2 inch wall cavity.
• Insulation placed between joists, rafters, and studs does not retard heat flow through those joists or studs. This heat flow is called thermal bridging. So, the overall R-value of a wall or ceiling will be somewhat different from the R-value of the insulation itself. That is why it is important that attic insulation cover the tops of the joists and that is also why it is recommend to use insulative sheathing on walls.

Some quick facts about R value are:

• One type of insulation maybe thicker or thinner, but if the R value is the same they should insulate equally.
• The average recommended R value for basement insulation in North America is R-12.
• The R value is substantially lowered if there is any air or water/moisture leaks.
• The standard R value for house insulation varies based on climate and temperature
• 1 inch of insulation is equal to 30 inches of concrete.

There are different types of house insulation materials, each having a different R value.
Some of the best insulation materials are:

• House Insulation R value of Blown in Cellulose Insulation is 3.70 per inch
• House Insulation R value of Fiberglass Insulation is 3.14 per inch
• House Insulation R value of Expanded Polystyrene is 4.00 per inch

Protecting Your House Insulation and its R value Protecting your house insulation and keeping your R value high is extremely important. Water is one of the biggest concerns in regards to R value and house insulation. If moisture/water gets into your house insulation, it lowers the R value. The moisture will weigh down the insulation leaving gaps and bare spots.

R-value Home Insulation Tips It's important to remember when buying home insulation, that the home insulation materials with the highest r-value may not be the most cost-effective. When insulating your basement wall to an r-value of r-12, it might be less expensive to use 2 layers of home insulation materials with an r-6 r-value rating instead of 3 r-4 r-value rated home insulation materials.
Another home insulation tip is to buy your home insulation based on its r-value not its weight or thickness. The last and most important tip for home insulation is to protect your insulation from water and moisture. Just 4% moisture in your insulation can reduce the thermal efficiency, in that area, by up to 70%.

R-Value Table

Material	R/ Inch
Fiberglass Batt	3.14
Fiberglass Blown (attic)	2.20
Fiberglass Blown (wall)	3.20
Rock Wool Batt	3.14
Rock Wool Blown (attic)	3.10
Rock Wool Blown (wall)	3.03
Cellulose Blown (attic)	3.13
Cellulose Blown (wall)	3.70
Vermiculite	2.13
Autoclaved Aerated Concrete	1.05
Urea Terpolymer Foam	4.48
Rigid Fiberglass (> 4lb/ft3)	4.00
Expanded Polystyrene (beadboard)	4.00
Extruded Polystyrene	5.00
Polyurethane (foamed-in-place)	6.25
Polyisocyanurate (foil-faced)	7.20

Home Insulation Can Make a Difference

Home Insulation

Electricity, oil, and gas bills - all homeowners pay for one or more of these utilities. No matter where you live, your home will be more comfortable and energy efficient with the right insulation.

A properly insulated home reduces heat flow, using less energy in the winter for heating and less energy in the summer for cooling. Simply put, insulation helps reduce the costs of heating and cooling your home because heat travels. Heat flows naturally from a warmer to a cooler space. In the winter, heat flows out; in the summer, heat flows in.

In the winter, this heat flow moves directly from all heated living spaces to adjacent unheated attics, garages, and basements, or to the outdoors; or indirectly through interior ceilings, walls, and floors. During the cool season, heat flows from outdoors to the house interior.

To maintain comfort, the heat lost in winter must be replaced by your heating system and the heat gained in summer must be removed by your air conditioner.

The term "home insulation" generally means the practice of providing a barrier of some kind to prevent the transfer of heat either in or out of the home. Reasons for insulating include increased comfort, energy efficiency and cost savings.

Insulation Materials

Traditional insulation materials:

· Fiberglass insulation is probably the most common of materials. It's made of many microfibers spun from molten glass and is usually pink or yellow in color.

· Rock wool is from rock, spun from molten rock instead of glass and is usually brown or gray in color.

· A variation on these two is slag wool, which is fiber spun from molten slag.

· Cellulose is made from shredded newspaper or cardboard, and chemically treated to make it fire and insect resistant.

New and alternative insulation materials:

· Plastic fiber made of mainly recycled plastic milk bottles.

· Polyurethane has the highest R-value of any other material for any thickness.

· Polystyrene also has a high R-value, good moisture resistance, high structural strength,

· Concrete block insulation combines concrete with a variety of other materials, including polystyrene beads, perlite beads (expanded volcanic glass), or wood chips.

· Natural fiber insulation is most often used in countries that are not heavily industrialized. Fibers used include wool, hemp, flax, and cotton.

· Straw bales were popular over a century ago and are enjoying renewed interest, as are straw panels made from a process invented in the 1930s, in which straw is fused into flat panels without the use of adhesives.

Types of Insulation

There are a number of different types of insulation:

· Rigid Board Insulation: also known as slab, board, or foam board insulation is made to be used in confined spaces like basements, foundation slabs, crawl spaces or exterior walls.

· Batts and Blankets: are different words for essentially the same product. Batts are insulation blankets that have been cut to a certain size, while blankets refer to the uncut rolls themselves.

· Loose Fill Insulation: is most often used as attic insulation in unfinished attics. It is often blown in with a blowing machine, or for smaller spaces, can be poured directly from the bags.

· Spray Foam Insulation is one of the best forms of insulation available as far as R-value.

Radiant Barrier Insulation works by reflecting heat or thermal energy either away from a structure to keep it cool, or attracting it to keep it warm.