Picking the right caulk can be the hardest part of any caulking job. Most hardware stores carry dozens of different products, each promising better results than the other. If you use the wrong caulk, the joint will fail long before it should, which means that you'll need to do the job all over again. Although some manufacturers now include helpful job-specific labels, others provide little information or overstate their products' performance. Here's how to pick the right product for whatever job is at hand.
CHEMISTRY COUNTS
Despite the dizzying selection, caulks are all made from one of four base, or backbone, polymers: latex, silicone, polyurethane or rubber. The base polymer determines specific characteristics, such as what materials it will adhere to, how easily joints can be smoothed, durability and paintability. Most caulks are sold in long tubes, and you apply them using an inexpensive, hand-pumped caulk gun.
LATEX
Also labeled as acrylic caulk, vinyl caulk or sealant, water-based latex products are the easiest to use, the least expensive and handle the widest range of applications. Latex caulks don't contain volatile chemicals, which means you can smooth joints with a wet finger and clean up excess with soap and water. All latex caulks can be painted, or you can also find a wide palette of pretinted caulks.
Latex-based caulks break into two sub-groups: less expensive acrylics and better-quality "siliconized" latexes. Acrylic latex is fine for sealing areas that won't face major temperature changes or high moisture levels, such as interior windows, doors and trim. Siliconized latex caulks contain a small amount of silanes (a form of silicone) to promote better adhesion. (This is not the same as 100 percent silicone caulk; see below.)
The best siliconized latexes are a good choice for heavy-duty work, such as exterior windows and doors, and caulking seams in kitchens and bathrooms, and to keep moisture out of walls and floors.
SILICONE
Silicone sealants were first used to bond glass panels to skyscrapers - afar more demanding job than most home improvement projects. Because they stay flexible at all temperatures, are completely waterproof, bond well to almost everything and won't support mildew growth, silicones are used around sinks, tubs and shower stalls.
Silicones come in two types: neutral cure or acid cure. Acid-cure silicones work best on nonporous surfaces such as glass and glazed tile, but they can corrode metal and etch some plastics. Neutral-cure silicones work well on metal and wood .
Silicones aren't perfect. For starters, these caulks are hard to smooth, and most won't hold paint (one exception is GE's new XST paintable silicone). If you need to recaulk, the old residue is almost impossible to remove.
POLYURETHANE
Polyurethanes excel as outdoor caulks. Since they are non-corrosive, extremely tear resistant and stick reliably to almost anything, they're a good choice for joints between dissimilar materials, such as metal-to-masonry joints around chimneys, wood-to-concrete joints at the sill plate, and masonry joints in driveways and concrete slabs.
Polyurethanes are not naturally ultraviolet resistant, so exterior joints should be painted or otherwise protected from sunlight. Tooling joints isn't as easy as with latex caulks, but easier than with silicones.
The biggest downside to this type is price: Polyurethanes are more expensive than most other caulks. Use them where strength, durability and weatherproofing are most important.
RUBBER
These products are made with synthetic rubber compounds such as isoprene, butadiene, nitrile and styrene. Rubber caulks will also stick to almost everything (but they melt styrofoam) and will even work with damp and oily materials. Their biggest downside is their smell; the solvents used are highly flammable and dangerous to breathe. For that reason, this caulk should only be used outdoors. Another drawback is shrinkage: After the solvent evaporates, the bead can shrink by as much as 35 percent.
Handy? Get Your Gun
For most projects, you'll want to use a standard 10-ounce caulk cartridge. For it, you'll need a caulk gun ( above ). There are two basic types of hand-operated guns. Ratchet guns (about $3) have a notched piston, which pushes the caulk out. To stop the flow of caulk, you have to twist the piston with your free hand to disengage the ratchet. Smooth-rod guns ($5 to $10) are easier to use. To release piston pressure and stop the flow of caulk, you simply press the quick-release plate above the handle with your thumb.
For small jobs, like caulking around a new faucet or making minor repairs, consider buying a squeezable tube (right).
LAYING A PERFECT BEAD
Once you've decided what caulk to use, the perfect caulk job depends upon careful prep work and application. To clean old caulk and soap scum from tiles and porcelain surfaces, first use a razor knife or caulk remover then wipe down the entire surface with a residueless solvent, like isopropyl alcohol. Remove any mildew with a solution of one part bleach to two parts water. For stone, brick and concrete surfaces, use a wire brush to remove dirt and crystallized minerals, then vacuum up loose debris. With wood, scrape away loose paint and old caulk, then prime any bare spots.
Most caulks are designed to be used between 40 and 90 degrees. On the lower end of their working temperature, most caulks get thick and difficult to squeeze out. To prevent this, keep the tubes indoors until you need them, or store them in an insulated cooler when working outside in the cold.
These removable caulks are good choices for sealing drafts around older, double-hung windows.
To start a tube, most pros cut the tip of the tube at a 45-degree angle, although some prefer a straight cut for caulking corners. Whichever style you choose, don't make the opening too big. Cut the tip where its diameter matches the width of the gap you're filling. Then poke a hole in the tip to release the caulk. (Most caulk guns have a handy fold-out tool for this.)
Caulked joints should have a concave shape, with thick sides to ensure good adhesion and a thinner middle to allow the joint to expand and contract. If the caulk sticks completely to the back of the crack it will be less able to stretch and more likely to pull away or tear. To prevent this, you can use a plastic foam backer rod in gaps over one-quarter inch thick. Available in several diameters, backer rods not only prevent sagging, they also provide extra insulation and save caulk.
For an extra-neat caulk job, mask both sides of the gap with painter's tape. As you caulk, maintain even pressure and keep the tip moving.
To apply the caulk, the pros are equally divided between the push and pull methods. Pull advocates say their method produces a smoother bead, while caulk pushers claim their method forces more caulk into the joint. Whichever you choose, the key is to squeeze out an even, full bead that completely fills the crack. As you near the end of the joint, release the handle pressure to avoid excess.
Finish by smoothing the bead. This tooling does more than smooth the surface: It forces material into the gap, fills minor voids and pushes material against the sides to ensure good adhesion. The most common tooling device is your finger, but you can also use an ice cube, the back of a spoon or a commercial device. Whatever you use, try to tool the joint just once: Overtooling can remove too much material from the joint. Minor bumps can be trimmed off with a razor blade after the caulk has cured.
Recently I had my heating ducts cleaned in my house after finishing a renovation project. The duct cleaning company used a video camera to inspect my ducts before and during cleaning, what a sight to behold! There were pieces of drywall left over from the original construction and of course lots of dust. I talked to many companies prior to choosing Anderson duct cleaning, and as they explained, the main difference is two fold; one if you don't use a service that actually contacts all the areas of your ducts you will not remove the dust that is attached to your ducts, and two; using a camera guarantees that all the dust and debris is being removed. Shawn, the owner, also gave me a great tip, when doing any kind of work in your home that can generate dust, close off your cold air returns to stop any dust from entering your duct work.
A typical house contains dust from pollen, spores, pet dander, lint, bacteria, etc. Even regular home activities like cooking or dusting add to the dust in the air inside the house. Such dust particles results in irritation of eyes and on entering the respiratory system, may cause respiratory disorders, damage to the lungs, or in unique cases, even cancer.
I now have two transparent inspection plates in my furnace, one on the cold air return and the other on the supply side duct work. As Shawn explained, after the major duct cleaning, I will now only have to have my cold air ducts cleaned when I can visibly see dust starting to collect in the duct work. Considerably cheaper than having whole system cleaned. The secret to keeping your supply side duct work clean is using a proper air filter. Shawn recommended staying away from cardboard edged filters as they often collapsed inside the cold air return and allowed dust and contaminates to pass.
In order to keep the quality of the air inside the home healthy, good quality furnace filters for your furnace unit should be used. There are various types of filters available on the market. These can be disposable, reusable or refillable. They're usually made from materials like fibreglass, metal, man-made or natural fibres. The efficiency of a filter is decided by fibre size, fibre density, airflow rate and particle diameter. Different types of filters available in the market are:Panel Filter- These types of furnace filters commonly consist of 1" fibreglass filter installed in the ducts. However, these furnace filters are not very effective in removing dust from the air, as its primary function is protection of the internal fan and minimizing dust on the heating coil. These are a very basic filter and can trap only larger particles from the air.
Washable/Reusable Filters- These are meant for extended use, and with regular cleaning and maintenance serve a very long life. Their downside is that it is nearly impossible to get completely cleaned and therefore adds resistance to the airflow. These types of furnace filters are also not very effective in trapping very small particles.
Pleated Filters- These are a modified kind of panel filters that have pleats or folds to increase its surface area. This design change makes it more efficient at trapping dust particles due to increased surface area. However, here too, the furnace filter starts resisting airflow once it starts collecting dust particles and thus should be replaced regularly.
High Efficiency Pleated Filters- These filters have an additional component of electrostatic charge that is designed to capture extremely small particles and various allergens, which make-up 99% of the particulate composition of the air. However, even these should be changed at regular intervals to maintain the air quality, and the airflow. Alternatively, refillable furnace filters are also available in this type.
High Efficiency Particulate Air (HEPA) Filters- These are extended filters that are able to remove sub-micron particles with high efficiency. HEPA filters have corrugated separators that have the core filters folded back and forth over it. This gives strength and also facilitates air passage between the pleats. However, these types of filters are not designed to fit most of the standard furnaces, as they require a separate system that includes a fan and a filter.
Choosing an air filter can be a daunting task with the number of filters and varying prices. One tip is common with all the experts that I read and watched on TV, if you can see through your filter then it no good. Most recommended the pleated type of filter which gives you more surface area of filter. These filters can then be chosen by the size of particulates that they will pass. The more particulates they filter the more expensive they become. Electrically charged filters were recommended to be one of the better filters as they also come in a washable model. My particle model has a pretty standard 16 X 25 X 1 inch filter but there are cartridge filters available that are up to 5 inches thick.
Electronic air filters charge the particles as they pass which then attracts them to the filter. These filters can then be removed and cleaned in your dishwasher. Both the larger cartridge filter and the electronic air filter have to be custom fitted to your furnaces cold air return.
Remember to periodically to check your furnace filter as the more particulates they collect the more frequently they should be changed as they will affect the air flow to your furnace.
Written by Roger Frost
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Air Barrier – Its Design and Purpose by the Orillia Home Inspector
In Ontario the air barrier in a home is installed under the authority of the Ontario Building 9.25.4.3. Installation of Vapour Barriers
(1) Vapour barriers shall be installed to protect the entire surfaces of thermally insulated wall,
ceiling and floor assemblies.
(2) Vapour barriers shall be installed sufficiently close to the warm side of insulation to prevent
condensation at design conditions.
Where a vapour retarder is employed, the opposite wall surface must provide a permeable surface to allow drying to occur. Thus, in hot, humid, cooling climates, where a vapor retarder is employed at the exterior, the interior wall surfaces should be permeable. Novapor retarder paints, kraft-faced insulation, or vinyl wall coverings should be used. Conversely, in northern heating climates, with interior vapour retarders, the exterior wall coverings should be vapour permeable. This simply means that in warmer climates where cooling is the main concern, the vapour barrier would be installed on the outside of the insulation.
House wraps are a permeable surface which, while protecting your home from the elements allows moisture to pass. This allows any moisture that is between your vapour barrier and house wrap can escape and evaporate rather than collecting in your wall system. The primary attribute of house wraps is their ability to operate as air infiltration barriers while not forming an impervious vapour barrier. When placed over the exterior surface of the wall sheathing, the material allows moisture vapour to escape from the frame wall cavity while reducing convective air movement in the insulation, thereby helping to maintain the composite R-value of the wall.
The Dew Point of your house is the area where warm moist air will convert to moisture. The dewpoint is a measure of atmospheric moisture. It is the temperature at which air must be cooled in order to reach saturation (assuming that air pressure and moisture content are constant). As the surface of the earth cools at night, warm moist air near the ground is chilled and water vapour in the air condenses into droplets on the grass and other objects. Dew is particularly heavy on clear nights, when the earth cools rapidly. When a blanket of cloud insulates the earth, the cooling rate is slower. The greater the difference between the temperature and the dew point, the drier the air
When warm moist air infiltrates your vapour barrier, and passes through to your exterior wall, when it meets a cold surface or void, moisture is created as it cooled to its dew point. This can cause wet insulation, frost on exterior walls and in some cases even mould.
Prevention is possible by ensuring all your insulation is covered by a vapour barrier, most codes call for a minimum of 6 mm poly, and all penetrations are overlapped and taped by Tuck tape, the red tape not the silver duct tape of Red Green fame. All electrical boxes, windows, switches, and vent penetrations should be tightly sealed.
Basements are more susceptible to breaks in vapour barriers due to the fact that most services are located there and many installers fail to replace insulation and repair holes in vapour barriers etc. This can be increased if you have laundry facilities located in your basement and an open sump hole which contains water.
Humidity is the main factor of the creation of moisture and if you live in a climate where the humidity is less than 35% this would not be an issue for you. So if you have high humidity using a dehumidifier in your basement can alleviate these moisture problems.
The Fire Code is a subset of the Building Code . It prescribes construction and safety issues as they relate to how the building is required to perform should it catch fire. A significant distinction with the fire code is that it can apply retroactively .
The Fire Code can be applied retroactively A new Fire Code was developed that applies to specifically to basement apartments. The code applies to all basement apartments whether existing or new. Owners must ensure that their apartment complies with the new Fire Code and must obtain a certificate of compliance.
There are usually four components of the Inspection that must be met:
1. Fire Containment or Separation of Suites
2. Fire alarms – Units must have working smoke alarms
3. Egress – There must be safe way out for occupants.
4. Electrical – Must have ESA inspection.
By-laws are created in some municipalities to prevent basement apartments as a nuisance protection for the neighbours.
Basement Apartments – The History
After 1993, a permit was required to change a home from single family to multi-family.
In 1994, the government in Ontario said that we could ignore local bylaws that prohibited second dwelling units in houses if certain conditions were met.
In 1994, the province set new Fire Code rules for basement apartments. A deadline was established for all existing basement apartments to upgrade to the new fire code.
In 1995, the Provincial government told municipalities that they could enforce their bylaws regarding basement apartments. A grand-fathering clause says that apartments existing before November 1995 do not have to meet local bylaws.
TWO-UNIT HOUSES (SECOND SUITES) Barrie ON – Local By-law
WHAT IS A TWO-UNIT HOUSE?
A two-unit house is a building that contains two residential dwelling units. Commonly, a two-unit house starts as a single dwelling unit (detached, semidetached or townhouse) with a second dwelling unit created within the house later on. The second unit is sometimes referred to as a second suite, an inlaw suite or a basement apartment. Duplexes & semi-detached units located on the same property are also considered as two-unit houses.
Effective January 1, 2004 the City of Barrie requires every two-unit house within the city to be registered. As part of the registration process, the City will confirm that the two-unit house is legal under the City’s Zoning By-law, and that the house complies with several health and safety regulations.
WHY DO TWO_UNIT HOUSES NEED TO BE REGISTERED?
There are probably a couple thousand two-unit houses in the city. Concerned that many of these units may be illegal and/or unsafe for the occupants, the City of Barrie has adopted a by-law to require every two-unit house to be registered. Through the registration process the house will be inspected to confirm compliance with the Zoning By-law, the Building Code, the Fire Code and the Property Standards By-law. Any unregistered two-unit house is a contravention of the Registration By-law.
HOW OFTEN DO I HAVE TO REGISTER?
Registration of a two-unit house is a one-time event. Under the current legislation, you do not have to re-register, unless your registration was revoked.
CAN THE CITY REVOKE BY REGISTRATION?
Yes. The registration does not need to be renewed, but you must always continue to maintain your building in compliance with Part 2 of the Fire Code and with the Property Maintenance By-law. If your building is inspected, usually at the invitation of a disgruntled tenant, and contraventions of the maintenance regulations are found, you will be served an order to remedy the contraventions within a time limit. If you do not make the repairs within the time specified, you may face penalties under either the Fire Code or the Property Standards By-law. In addition, the registrar may revoke your registration. Any continued use of the house as a two-unit house without being registered would be a separate violation, subject to its own penalties. Registration can also be revoked if the house ceases to be used as a two-unit house. Applications to re-register a two-unit house would be subject to the rules and fees in effect at that time.
A dwelling unit is a room or suite of rooms operated as a self-contained housekeeping unit that includes independent cooking, eating, living, sleeping and bathroom facilities.
2.0 Buildings Covered by the New Fire Code Regulation ?
The regulation applies to detached houses, and semi-detached houses, and row houses that contain two existing dwelling units. The two dwelling units may be located anywhere in the house.
3.0 What are the Requirements ?
In general, the regulation contained in the Ontario Fire Code addresses four fire safety issues:
3.1 Fire separation
The owner has three options for compliance with the fire separation for each dwelling unit
3.2 Means of Escape.
Four options are provided for compliance with the means of escape from each dwelling unit.
3.3 Smoke Alarms
Depending on the option selected for fire separation and means of escape, it may be necessary to install electrically wired, interconnected smoke alarms throughout the house. Interconnected smoke alarms are designed to sound simultaneously when any one smoke alarm is activated, providing early warning to all occupants of the house at the same time.
Where interconnected smoke alarms are not installed, every dwelling unit must be equipped with a battery operated or electrically wired smoke alarm on every floor level that contains a bedroom or sleeping area.
All smoke alarms must be maintained in working condition, and they must be audible in the bedrooms when the bedroom door is closed.
3.4 Electrical Safety
The owner must also arrange for the house to be inspected by "the Electrical Safety Authority" and to correct all fire safety hazards identified through this inspection.
4.0 Who is Responsible With Complying With the Regulation ?
The owner is responsible for complying with the provisions of the Ontario Fire Code. Penalties for non-compliance can be up to $50,000 fines and up to one year in prison for individuals.
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Many new buildings have features such as passive solar design, photovoltaic systems and solar thermal systems. With the new energy awareness that has been created and the governments involvement in promoting green energy saving concepts, green will be introduced to more homes and systems. The energy consumed by homes if roughly 40% in the United States of America and will become a principal target for controlling sky-rocketing energy costs. Up to 85% of the energy used today is non-renewable and is not projected to change in the foreseeable future.
Passive design refers to home design which uses natural methods of heating and cooling, and which requires few or no mechanical devices and minimal or no consumption of other fuel.
Heating
Passive solar heating uses the sun’s energy to heat a home. Typically, the home is designed and oriented to collect sunshine through large, south-facing windows. Sunlight shines into the home onto materials with high thermal mass , such as concrete, masonry or stone, which absorb sunshine and store it as heat, slowly releasing it over time to warm the home interior.
Active solar heating uses the sun’s energy to heat a home, but heat is distributed through the home with the help of mechanical equipment such as fans, requiring the use of some electricity.
Green Improvements
LOW-FLOW TOILETS
Toilets consume 30% to 40% of the total water used in homes, making them the biggest water users. Replacing an older 3.5-gallon toilet with a modern, low-flow 1.6-gallon toilet can save an average of two gallons-per-flush (gpf), or 12,000 gallons of water per year. Low-flow toilets usually have 1.6 gpf marked on the bowl behind the seat or marked inside the tank.
Another method for reducing the volume of water used with each flush is to install a water-filled plastic bag (called a displacement bag ) in the water tank. The old version of the displacement bag was a brick.
Protecting the Home Foundation
Moisture allowed to penetrate next to the foundation can cause several problems:
Softening the soil : Moist soil may be less able to support the weight of the structure above. Ontario Building Code requires larger footings in moist or un-disturbed soil.
Expansive soil : Certain types of soil, especially certain types of clay, expand to many times their original size as they absorb moisture. Expansive soil can easily damage foundations.
Foundation undermining : E nough moisture flowing under a foundation can carry away soil and leave the foundation unsupported in areas.
Microbial growth : Moisture allowed to collect in crawlspaces and basements may create conditions which encourage the growth of microbes such as mould fungus and soil-borne bacteria which may represent potential health hazards.
Slope Grade Away from Foundation
Grade around the home perimeter should slope away from the foundation for at least six feet. The slope should effectively route surface run-off away from the foundation.
Hillside Run-Off
Homes built on hillsides should have a feature installed which will route surface runoff away from the foundation. Swales and drainage ditches are two commonly used methods.
Planting Beds
Planting beds located next to the home may create problems by holding moisture next to the foundation.
Downspouts
To minimize erosion and route run-off away from the foundation, downspouts should have extensions or should terminate at a perimeter drain or splashblock. Some method should be used to prevent erosion.
Engineered Lumber
Engineered wood products use recycled/reconstituted wood chips or strands and finger-jointing (the process of gluing larger pieces of wood together) to produce a variety of building products such as structural framing lumber and trim material.
Waste wood and entire trees can be used to produce products, regardless of species and age.
Engineered wood is generally straighter, more stable and more structurally consistent than dimensional lumber. In joist and rafter applications, the reconstituted products are particularly useful because they can span long distances with less sagging than similarly-sized conventional lumber.
Cost
Engineered wood is generally more expensive than dimensional lumber, but cost is offset to some degree by labor savings and improved quality.
Types of Engineered Lumber
Oriented Strand Board (OSB)
OSB has replaced plywood in many applications. It is manufactured using waterproof heat-cured adhesives and rectangular-shaped, aligned wood strands. Strand direction changes in each layer in a manner similar to the way the veneers within a sheet of plywood alternate direction. This results in a structural engineered wood panel that shares many of the strength and performance characteristics of plywood
Finger-jointed Studs
Finger-jointed studs are manufactured by milling tightly-fitted joints into short pieces of lumber which would otherwise be considered scrap. These short pieces are glued together using a method that creates joints that are stronger than the wood. Joints will lose strength, though, if material is not protected from weather.
I-beams
I-beams are framing members typically used as floor joists and sometimes as rafters. They are “I” shaped in cross section, dimensionally stable, available in a variety of structural ratings and are produced in lengths up to 60 feet. They consist of a plywood or oriented strand board (OSB) web to which a top and bottom chord is attached, usually either 2 x 2, 2 x 3 or 2 x 4, depending on the structural rating of the I-beam.
Microlams
To produce Microlam® Laminated Veneer Lumber (LVL), sheets of veneer peeled from logs are carefully dried, ultrasonically graded for strength, and evaluated to ensure uniform thickness and moisture content. The sheets are coated with adhesive, layered, and subjected to heat and pressure to achieve a permanent bond. As with I-beams, Microlams are available in long lengths.
Glu-Lams
Glu-Lams are beams manufactured by gluing together layers of dimensional lumber. Engineered beams are typically more stable and stronger than similar sized dimensional beams and can be manufactured with a camber . Glu-Lam beams can also be manufactured in large sizes which would be much more expensive if milled from a solid piece of wood. Glu-Lams are often left exposed. Building beams by laminating smaller pieces of dimensional lumber allows for more efficient use of wood and helps save trees.
Parallams
Parallams are engineered wood beams manufactured by gluing together aligned wood strands and bonding them using a microwave process.
Wall Framing
Wood and steel wall framing members act as thermal bridge s in transmitting heat through the building envelope. Value engineering uses two methods for reducing heat transfer from thermal bridging.
A thermal break is a layer of insulation which interrupts the conduction of heat through building envelope framing members.
Reducing the number of framing members in the building envelope. By installing studs on 24-inch centers instead of 16-inch centers, fewer studs are used, which means a greater percentage of the overall exterior wall, floor or roof cavities will be filled with insulation.
Structural Insulated Panels (SIP’s)
Structural insulated panels are high performance building panels used in floors, walls, and roofs in residential and light commercial buildings. They are an alternative to conventional framing methods.
The panels are made by sandwiching a core of rigid foam plastic insulation between two structural skins of oriented strand board (OSB). Other skin material can be used for specific purposes. SIPs are manufactured under factory-controlled conditions and can be custom designed for each home. The result is a building system that is extremely strong and energy efficient because there are no wall studs to transmit home heat to the outside. Panels are available in a variety of sizes, thicknesses and core/skin materials.
Insulating Concrete Forms (ICFs)
Insulating concrete forms are forms for poured concrete walls which are designed to remain in place as a permanent part of the wall assembly.
The forms, made of a foam similar to Styrofoam, are made up of pre-formed, hollow, interlocking blocks. As blocks are assembled, rebar is installed, and then concrete is poured to fill the cavities, so that once the concrete is dry it forms a post and beam grid inside the blocks.
In addition to providing a continuous insulation and sound barrier, the foam forms have plastic strips embedded which provide a means for attaching interior and exterior wall coverings.
Insulation
Insulation is rated by its thermal resistance, called R-value, which indicates its resistance to heat flow. Higher R-values indicate greater effectiveness at reducing heat flow. The R-value of thermal insulation depends on the type of insulating material, its thickness and its density. Installing more insulation in a home increases its R-value and helps keep heat from moving through the building envelope.
The total wall assembly R-value will depend upon what materials are installed in the wall, floor or roof assembly , not just the R-value of the insulation. In calculating the R-value of a multiple-layered wall, floor or roof assembly , the R-values of the individual layers are added together. The R-value of a wall assembly is also affected by the quality of the installation and the properties of the insulation material.
To a certain extent, more tightly-packed wall cavities will allow less air-flow through the wall assembly, which reduces the amount of heat flow since air carries heat.
Insulation packed too tightly will lose some of its effectiveness because most insulation works by trapping air in microscopic air pockets. When these tiny pockets are crushed, R-value is reduced.
Insulation is also affected by thermal bridging . Thermal bridging commonly occurs where framing members in the building envelope interrupt the insulation. Wood studs have an R-value of approximately R-1 per inch. Fibreglass insulation is approximately R-3.3 per inch. This means that studs will conduct heat through the wall more quickly than the insulation, forming a thermal "bridge" between the conditioned air interior and the exterior.
Because heat rises, ceilings and attics typically have more insulation installed than walls or floors
Air Movement in Buildings
The building envelope consists of those parts of the floor, wall and roof assemblies designed to control the loss of conditioned air. Conditioned air refers to air which has been warmed, cooled or had moisture added to or removed from it.
Building science refers to the study of how moisture, heat and air move through buildings and how their movement affects human health, comfort and the cost of operating homes. Air movement is an important influence on indoor environments because air commonly moves across building envelopes. We want to keep control of indoor air quality, and air movement across the building envelope has the potential to affect the quality of indoor air dramatically.
Circular air movement occuring within a building envelope is called circulation. Air movement across the building envelope is called infiltration if air is moving into the conditioned space and exfiltration if it is moving out.
Air movement in a home can create uncomfortable moisture or temperature levels, or introduce dust, pollen, mold spores, radon or other pollutants or health hazards into indoor air.
INDOOR AIR MOVEMENT
Air movement through the building envelope is caused by the following:
Depressurization of buildings by mechanical ventilation devices and the combustion process.
Poorly-balanced HVAC systems –heating and cooling equipment both use blowers to distribute conditioned air throughout buildings. Depending on how well the system is balanced, this can establish air pressure differences in various parts of a building, which can cause air to move in or out through the building envelope.
Ventilation fans for bathrooms, laundries and range hoods all push conditioned air to the outside which must be replaced. Typically, this make-up air has come from air infiltration around doors and windows and through other gaps in the building envelope.
Combustion processes in appliances such as boilers, furnaces, heating stoves and water heaters. They pull air from the home interior as they exhaust the products of combustion to the exterior.
Temperature differentials between indoor and outdoor air.
Thermal buoyancy describes the action of air as it is warms. Because heated air is less dense it rises, moving from a cool, high-density area toward a warm, low-density area.
Stack effect describes the action of warm air rising through a building. As warm air rises, it pulls cold make-up air into the home through the lower building envelope and pushes warm air out through the upper building envelope. This can have a significant effect on homes, pulling undesirable hot or cold air, moisture or environmental pollutants and hazards (radon) into the home.
Convection currents , or the movement of cooler air being pulled in to replace rising warm air, will establish convection currents at any place in the home in which significant temperature differences exist. This occurs mainly in living space and attics. Supply and return registers are key points of temperature differences, but also key points of pressure differences caused by Make-Up Air
As air is exhausted from the home by the methods mentioned above, it must be replaced by make-up air. Unless ventilation devices are deliberately installed to provide make-up air, it will be pulled into the home through the building envelope. Uncontrolled make-up air may carry with it excessive moisture or heat (or lack of heat). It may infiltrate from the exterior, the crawlspace or the attic.
In extremely tightly built homes, make-up air has been supplied from sewers after water was sucked out of the plumbing traps. Installing a Heat Recovery Ventilator (HRV) or Energy Recovery Ventilator (ERV) offers more control over the supply of make-up air, allows for more efficient use of heating and cooling equipment and reduces heating and cooling costs
Heat and Energy Recovery Ventilators
Inspecting HRVs and ERVs lies beyond the scope of a General Home Inspection, but inspectors should be able to recognize them.
HRVs use a heat exchanger to transfer heat between home exhaust-air and make-up air without allowing the two airstreams to mix. This exchange pre-warms (or pre-cools) make-up air, which in turn lowers heating and cooling costs.
ERVs perform the same function but in addition, they also transfer moisture. Systems are available in different sizes in order to maintain as closely as possible an ideal 3.5 air changes per hour .
HRVs and ERVs are typically installed in line with the home heating/cooling ducts and may include filtration devices such as High Efficiency Particulate Air (HEPA) filters.
Air Barriers
Air barriers are assemblies or components designed to resist the flow of air through the building envelope by resisting air pressure differences. They may consist of sealed drywall, exterior wall sheathing or even tightly-packed insulation (sprayed cellulose or foam). They may be installed anywhere in the wall, floor or ceiling assembly, and toward the exterior or interior.
Air barriers should be:
impermeable to air flow.
continuous around the entire building or living space perimeter.
permeable to water vapor–moisture impermeable barriers may cause condensation problems.
substantial enough to withstand the forces that may act on them during and after construction.
durable over the projected lifetime of the building.
Photovoltaic (PV) Systems
Photovoltaic (PV) is the term used to describe systems which convert sunlight directly into electricity. To collect sunlight, PV systems use either panels or shingles, although panels are much more common. Individual PV panels are called “modules” and a number of modules can be mounted together on racks to form an “array.”
An array may consist of modules connected together in a single string, or modules may be connected to form several strings within the array. This is important because shading one module in a string will shut down the rest of the modules in that string. If all the modules in an entire array are connected to form only one string, the entire array could be shut down by shading one module.
PV systems have no moving parts, have 20-year plus lifespans and no negative environmental impact once they’re installed. Typical panels are now around 15% efficient, although panels not yet publicly available approach 30% efficiency.
To help avoid this problem, some systems provide a “combiner box” in which electrical connections for individual modules are made inside an electrical panel mounted in an easily accessible.
Two types of PV systems are available, grid-tie and battery back-up.
GRID-TIE SYSTEMS
A “grid-tie” system is one in which, in a home conventionally connected to utility company power supplies, a special electric meter is installed which can spin both forward and backward, often called a “net meter”. When the PV system is producing more power than the home uses, the meter will spin in reverse. Utility companies review the results annually and if the system owner has produced more electricity than they have used, they typically receive compensation. Compensation agreements between PV system owners and utility companies vary.
It is typical for the utility to sell electricity to consumers at a price of, as an example, 11cents per Kilowatt hour (KWh), but will pay only a wholesale price of 4 cents per KWh to PV system owners who produce an annual surplus.
One of the disadvantages of the grid-tie system is that if the home loses power from the utility company, the PV system is designed to shut down automatically also, meaning that the home will be without electricity as long as no power is supplied from the utility provider. This feature is designed to protect utility employees working on power lines, since power from the PV system not used at the home goes out the service wires, through the transformer on the pole and into the utility companies’ electrical distribution system.
Inspection of PV Systems
Complete inspection of a PV system requires a qualified specialist. PV systems can produce lethal amperages and home inspectors without special training specific to PV should under no circumstances imply that they perform complete PV inspections. Proper grounding and bonding methods are crucial, line-side taps are not unusual and dangerous conditions my not be obvious to inspectors who feel comfortable inspecting conventional home electrical systems but are not PV-qualified.
Lighting: Bulb and Fixture Types
Energy Use in Home Lighting
Lighting accounts for 30% to 50% of a building’s energy use, or about 17% of total annual U.S. electricity consumption. Ninety percent of the energy emitted by incandescent bulbs is in the form of heat, and only 10% is in the form of light. This means that not only is money wasted on inefficient lighting, but using incandescent bulbs lights increases cooling costs.
There are many ways to build Green and with the change in our economy the government will be funding more efficient means of conserving energy. Ontario’s Premier has already indicated that they will not allow NIMBY’s ( Not In My Back Yard) to influence siting of energy saving or green initiatives. The wind turbines being located off the Scarborough bluffs is an example of Ontario’s determination to move forward with Green projects.
Professional home inspectors featuring Building Code Qualified personnel. Free WETT and Thermal Imaging inspection included. Starting at $199.00 for single bath residential home with Money-back guarantee if not 100% satisfied.
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