Roof Blog

Choosing a roof system

There are a number of things to consider when selecting a new roof system. Of course, cost and durability head the list, but aesthetics and architectural style are important, too. The right roof system for your home or building is one that balances these five considerations. The following roofing products commonly are used for steep-slope structures.

Asphalt shingles possess an overwhelming share of the U.S. steep-slope roofing market and can be reinforced with organic or fiberglass materials. Although asphalt shingles reinforced with organic felts have been around much longer, fiberglass-reinforced products now dominate the market.
Organic shingles consist of a cellulose-fiber (i.e., wood) base that is saturated with asphalt and coated with colored mineral granules.
Fiberglass shingles consist of a fiberglass mat, top-and-bottom layers of asphalt, and mineral granules.
Asphalt shingles' fire resistances, like most other roofing materials, are categorized by Class A, B or C. Class A signifies the most fire-resistant; Classes B and C denote less fire resistance. Generally, most fiberglass shingles have Class A fire ratings, and most organic shingles have Class C ratings. A shingle's reinforcement has little effect on its appearance. Organic and fiberglass products are available in laminated (architectural) grades that offer a textured appearance. Zinc or copper-coated ceramic granules also can be applied to organic or fiberglass products to protect against algae attack, a common problem in warm, humid parts of the United States. Both types of shingles also are available in a variety of colors.
Regardless of their reinforcing type and appearance, asphalt shingles' physical characteristics vary significantly. When installing asphalt shingles, NRCA recommends use of shingles that comply with American Society for Testing and Materials (ASTM) standards-ASTM D 225 for organic shingles and ASTM D 3462 for fiberglass shingles. These standards govern the composition and physical properties of asphalt shingles; not all asphalt shingles on the market comply with these standards. If a shingle product complies with one of these standards, it is typically noted in the manufacturer's product literature and on the package wrapper.

Wood shingles and shakes are made from cedar, redwood, southern pine and other woods; their natural look is popular in California, the Northwest and parts of the Midwest. Wood shingles are machine sawn; shakes are handmade and rougher looking. A point to consider: Some local building codes limit the use of wood shingles and shakes because of concerns about fire resistance. Many wood shingles and shakes only have Class C fire ratings or no ratings at all. However, Class A fire ratings are available for certain wood shingle products that incorporate a factory-applied, fire-resistant treatment.

Tile—clay or concrete—is a durable roofing material. Mission and Spanish-style round-topped tiles are used widely in the Southwest and Florida, and flat styles also are available to create French and English looks. Tile is available in a variety of colors and finishes. Tile is heavy. If you are replacing another type of roof system with tile, you will need to verify that the structure can support the load.

Ventilation and insulation are key. One of the most critical factors in roof system durability is proper ventilation. Without it, heat and moisture build up in an attic area and combine to cause rafters and sheathing to rot, shingles to buckle, and insulation to lose its effectiveness.
Therefore, it is important never to block off sources of roof ventilation, such as louvers, ridge vents or soffit vents, even in winter. Proper attic ventilation will help prevent structural damage caused by moisture, increase roofing material life, reduce energy consumption and enhance the comfort level of the rooms below the attic.

In addition to the free flow of air, insulation plays a key role in proper attic ventilation. An ideal attic has:

• A gap-free layer of insulation on the attic floor to protect the house below from heat gain or loss.
• A vapor retarder under the insulation and next to the ceiling to stop moisture from rising into the attic.
• Enough open, vented spaces to allow air to pass in and out freely. A minimum of 1 inch between the insulation and roof sheathing.

Buying a new roof system

Buying a new roof system is an important investment. Before you spend your money, spend time learning how to evaluate roofing contractors. You should insist on working with a professional roofing contractor. NRCA wants to assist you in getting the kind of results you expect—a quality roof system at a fair price. All roofing contractors are not alike, and NRCA recommends that you prequalify roofing contractors to get the job done right the first time.

The following guidelines will help you select a professional:

• Check for a permanent place of business, telephone number, tax identification number and, where applicable, a business license.
• Don't hesitate to ask a roofing contractor for proof of insurance. In fact, insist on seeing copies of his liability coverage and workers' compensation certificates. Make sure the coverages are in effect through the duration of the job. Many building and home owners have been dragged into litigation involving uninsured roofing contractors. Also, if a contractor is not properly insured, you may be liable for accidents that occur on your property.
• Check to see if the roofing contractor is properly licensed or bonded. Some states have specific licensing requirements, and others do not. Your state's Department of Professional Regulation or Licensing Board will have this information.
• Make sure the contractor is financially stable. A professional roofing contractor can provide current financial information about his company. Look for a company with a proven track record that offers client references and a list of completed projects. Call these clients to find out whether they were satisfied.
• Insist on a detailed, written proposal and examine it for complete descriptions of the work and spec ifications, including approximate starting and completion dates and payment procedures.
• Have the contractor list the roofing manufacturers with which his firm is a licensed or approved applicator. Most roof systems require special application expertise to achieve lasting quality.
• Have the contractor explain his project supervision and quality-control procedures. Request the name of the person who will be in charge of your project, how many workers will be required and estimated completion time.
• Check to see if the contractor is a member of any regional or national industry associations, such as NRCA. Being a member of industry associations demonstrates a commitment to professionalism.
• Call your local Better Business Bureau or Department of Professional Regulation to check for possible complaints filed against the contractor. Carefully read and understand any roofing warranties offered, and watch for provisions that would void it.
• Choose a company committed to worker safety and education. Ask the contractor what type of safety training he provides for his workers and what industry education programs they have attended. The best roofing contractor is only as good as the workers who install the roof system.
• Keep a healthy skepticism about the lowest bid. If it sounds too good to be true, it probably is. Many fly-by-night contractors' below-cost bids seem attractive, but these contractors often are uninsured and perform substandard work. Remember, price is only one of the criteria for selecting a roofing contractor. Professionalism, experience and quality workmanship also should weigh heavily in your decision.

Policies

1. Removal vs. Recovering over Existing Shingles
Removal of existing shingles is always recommended. Doing so ensures that the new shingles lay as flat as possible. Manufacturers strongly urge the procedure to ensure full warranty protection. Recovering the roof may cause the new shingle to form or mould to the contour of the original shingle roof—Which can cause water to travel sideways as well as down. This in turn can promote a leak that would not otherwise occur.

2. The Vapour Barrier
Once the shingles are stripped off and all the debris cleared from the roof and eaves-trough, eave underlayment is installed. There are several options to choose from, depending on the design and slope of the roof. The minimum underlay as per the Ontario Building Code is 25 lb. Glass Base Sheet. (Ask your representative about other underlay upgrades) Coverage is based on distance of the eave-projection.

3. Installation
All shingles are not the same when it comes to installation procedure. We follow the recommended procedure as per the manufacturer. This also ensures that your warranty is kept in good standing.

4. Ventilation
Air flow is essential to the performance of your roofing system. Insufficient ventilation can and will promote condensation in the colder winter months—and prevent hot air from exiting in the summer months—which can cause premature aging and deterioration of the new shingles and the wood deck. Dura flo air vents are 75 sq. inches in vented area, constructed of P. V. C. to withstand damaging U. V. light rays. Our vents are designed with a bird and rodent resistant screening. Venting is calculated by area and must be brought up to Ontario Building Code standards to ensure full warranty protection. Vents are available in 7 colours. OPTION: (Clear available for garage areas to allow extra light)

5. Valleys
Our 26 Gauge pre-painted steel Valley are installed at a 24” width with a 36” width of base sheet underlay. We expose the pre-painted metal surface and taper cut our shingles to allow for water drainage—Exposed metal surface helps shed snow and ice from the valley areas. The steel is hot-dipped zinc coated with a baked enamel surface to better inhibit corrosion and U. V. light damage.

6. Flashing Systems
Our 26 Gauge pre-painted steel Wall flashing are an essential component of your roofing system. Loose or poorly fit flashing will not only promote leakage but can affect the aesthetic appearance of your home. All step flashings are replaced in conjunction with the counter flashing. Replacement flashing are “Custom” made to fit and anchored with a lead plug . Again, a wide variety of colours are available.

7. Sealant
We use only Supra Expert Thermoplastic caulking. sealant on all flashings, nail-heads, skylights and other essential roof components.

8. Clean-up
After each workday a thorough clean-up of the site is performed, a sweep of the perimeter with a magnetic broom picks up loose nails and metal off-cuts. Advanced Roofing (Ontario ) Ltd has taken the forefront in recycling, with up to 90% of our job-debris being reused—Because of the lack of land fill space, helping preserve the environment!

9. Plywood or Wood Damage
With many roof decks in the past 30 years being constructed with 3/8” plywood, in some cases extensive replacement is required at an additional cost to the quotation. During most estimates or inspections our estimators can indicate to the homeowner about roof deck damage. But in some cases because of certain circumstances (ie: Two layers hide the true severity) Part of or the entire roof deck has to be replaced.

What creates an Ice Dam?

1. A heavy snowfall - enough to leave several inches on a roof.
The more snow left on a roof after a storm, the greater chance an ice dam may form.

2. Cold temperatures.
A heavy snow followed by several days of -08 degree Celsius temperatures is especially favorable.

3. Under ventilated and poorly insulated attic.
Heat escapes from the living quarters to the attic. The heat builds up, eventually warming the underside of the roof deck, causing a thawing effect on the roof. Water will then run down the roof eventually reaching the eaves. Since this area remains cold, the runoff from the melting snow begins to freeze, forming an ice dam. As the ice dam builds, it begins to trap more melting snow run-off, thus increasing the height of the dam.

How to Help Eliminate and Protect against Ice Dams In Three Easy Steps!

1. Install adequate attic ventilation.
Because ice dams form when a roof has warmed upper surfaces and cold lower surfaces, the solution is to equalize temperatures over the entire roof area. Heating an entire roof is impractical (and extremely costly), so the most effective solution is to create a cold roof surface.

To do that you’ll need a well designed attic ventilation system. The Ontario Building Code states that ventilation should be 50% at the eave and 50% at roof to create sufficient circulation of the air.

With an adequate attic ventilation system this creates an even temperature from eave to peak areas, thus greatly reducing the possibility of forming an ice dam.

2. Install adequate attic Insulation.
Attic insulation serves two purposes. First, and most important, it minimizes heat loss from inside the home. Second, adequate attic insulation diminishes the energy impact of having cold air flowing through the attic. The amount of insulation required depends on the area you live in, for the greater Toronto Area it should be an R-32.

3. Ice and Water Proofing Membrane Underlayment
This is the last line of defense against water infiltration. It’s important, because even the most efficient attic ventilation may not be enough! At Advanced Roofing (Ontario) Ltd we use only a premium grade of Ice and Water shield membrane. We feel this membrane gives you durability, quality, and a proven track record.

4. Install an eave-starter.
We also recommend that you install an eave-starter or drip-edge, in conjunction with the Ice and Water shield to better enhance the protective performance of your roof system. An eave-starter or drip-edge is a pre-formed metal edge that ensures the water will drain into the eaves-trough as well as create a reinforced base for the Ice and Water Shield to be adhered to.

We hope this gives you a better understanding of the Ice Damming effect. Remember next to your home’s foundation wall a roof is the second most important component of your home!

The Definition of value

To define the word VALUE we must first look at ones self. Many of us may find value in an inexpensive purchase, we may purchase an item, one of many similar lines, and feel as if we’ve made a deal, yet weeks or months later the product will fail, break or not meet your expectations. Left feeling taken, misled or even “ripped” off.

The “Art” of purchasing something is knowing exactly what you are paying for. Even if you’re purchasing by comparison i.e.: (Apples to Apples--Would you not opt for the apple that may be less bruised or blemished or for flavor over the price.)

The same theory should apply for a roof replacement—What VALUE do you put on your Home or your Roof…? For many homeowners their home is a sense of pride in ownership, they’ve invested hard earned money and time in creating a comfortable living environment for their family.

At Advanced Roofing (Ontario) Ltd we know the value in a roof purchase, we specialize in it. We take every roof replacement seriously, starting at your initial call for an estimate. Our Estimator/Consultants arrange a time to meet with the homeowner for an on-site quote. During the estimate process our estimators inspect, measure and assess your home needs. Our sales/estimators are specialists in the industry—as well as qualified installers. Product knowledge is our specialty, ability to tackle certain roofing scenario problems, and preparing an on-site comprehensive quotation, makes your estimate process enjoyable, and meets your specific roof application. After the contract is accepted and final confirmation on details as to color selections are finalized, a scheduled time line is issued for start-up. As your time-line start date approaches you will be contacted by our scheduler for delivery of materials and a disposal container.

During the application process the job is done as per the contract—We Do Not meander from the details of our contract—unless specified and coordinated in writing with the customer. Wood deck replacement if necessary is at the discretion of our installers. We do not install asphalt shingles over damaged or rotted decks. All our trades-people are skilled and experienced, and maintain a clean/safe work-site, taking into consideration the customers’ property and safety of others.

After Completion of the job a thorough inspection of the installation/job-site is done by the supervisor for deficiencies or debris. It is then signed for a completion certificate—any deficiencies are addressed and taken care of—then final invoicing takes place.

Upon final payment Warranty papers are then issued to the customer both for Workmanship and Material. Any questions retaining to coverage can also be broached.

Received with the Warranty package is a Service Contact form. We Warranty our workmanship for a period of up to Ten (10) years. If for any reason you may have a concern with your application or just a question, these contacts will be of great VALUE to you as the homeowner. We pride ourselves with our after-service program.

VALUE—When choosing a contractor look beyond just the specifications, consider all the other benefits you’ll receive in dealing with a professional and reputable, service-oriented roofing contractor.

The language of roofing from A to Z

Absorption: how a material accepts gases or liquid, such as moisture.

Aggregate: materials such as rock, stone, crushed stone, crushed slag, or marble chips used for surfacing or as a ballast in a roof system.
Alligatoring: the appearance of cracks on the surface of bitumen on a built-up roof; similar appearance to the skin of an alligator.

Aluminum: a non-rusting metal typically used for metal roofing and flashing.

Apron Flashing: a term used for a flashing that is situated at the juncture of the top of the sloped roof and a vertical wall or steeper-sloped roof.

Architectural Shingle: a shingle design that appears three dimensional.

Asphalt: a dark brown or black substance that is a byproduct of the refining process and can also be found naturally.

Asphalt Emulsion: asphalt particles mixed with an emulsifying agent such as bentonite clay and water.
Attic: the space above a ceiling and below a roof.

Ballast: an anchoring material, such as aggregate or precast concrete pavers, held in place by the force of gravity.

Base Flashing (membrane base flashing): plies or strips of roof membrane material used to close-off and/or seal a roof at the roof-to-vertical intersections.

Metal valley system

What's better, a metal valley or bringing the shingles together from either side to create a valley? – Olga, Toronto
 “A metal valley system is best”
 
In our opinion, a metal valley system is best. That’s because water, snow and ice shed from opposing slopes collects in the "valley" and, as a result, the valley is prone to more wear.

If you have a "closed" valley system, the heavy volumes of water collected causes premature wear of the shingles in those areas. Twenty years ago it was common to see mineral surfaced valley materials (which had ceramic granual covering, like shingles). We would always observe that the valleys would wear out before the shingles in the field of the roof.

Having said this, alternative valley methods are acceptable to shingle manufacturers. The two other systems are a closed valley system as you described, where shingles are extended from the lesser slope up and under the shingles from the opposing steeper slope. A "western" or "weaved" valley consists of every six shingle courses being run under the opposing slope in opposite directions.

As some customers prefer the appearance of closed valleys, Avenue Road Roofing still insists on installing metal valleys and appropriate underlayment materials underneath such assemblies. Some roofing contractors install closed valleys without underlays. You can’t see the difference when the roof is installed, but there is a big difference in workmanship.
When a very steep slope adjoins a much lesser pitched slope, it is recommended to manufacture the metal valley with a "centre stop" detail. This involves forming the metal with a standing seam in the centre of the valley. This is designed to divide the flow of water and prevent water from being forced under the lesser slope.

R-Value Calculator

A material’s R-value is the measure of its resistance to heat flow. It is important to know the R-value because many states or regions require that a roof system have a minimum amount of thermal resistance on commercial, industrial, and/or institutional buildings. The way it works is simple: the higher the R-value, the more the material insulates.

Some common roofing materials and their corresponding values for Thermal Conductance (C) and Thermal Resistance (R) are shown in the following table.

* Problems have been reported with regard to the use of Phenolic Foam roof insulation. Incidents of deck corrosion have been reported in cases where the insulation is in direct contact with steel roof decks and there is moisture present.

** Molded, Expanded Polystyrene Insulation, also referred to as MEPS, can have an R-value that will vary from less than 4.00 to slightly more than 4.00. The amount shown is an average amount used for roof system R-value calculations.

*** Extruded, Expanded Polystyrene Insulation is commonly used in Inverted Roof Membrane Assemblies (IRMA).

****Sprayed Polyurethane Foam (SPF) will have an R-Value of 7.14 when it is newly installed. After it ages a few months, the R-Value will reduce to somewhere around 6.88.

The C-value (C) is a measure of the Thermal Conductance of the material and is the reciprocal of R, or

C is determined only when the Thermal Conductivity (k) of a material is known.

Thermal Conductivity is the measure of the amount heat that will be transmitted through a one inch (1") thick piece of homogenous material, one square foot (1 ft.²) in size, in one (1) hour, when there is a one degree Fahrenheit (1° F) temperature change. The equation for "k" is:

Now let’s see how easy it is to figure the R-value. First of all, you need to know what the components of the roof system are. We’re going to figure the value of some common ones. Let’s assume the roof system consists of a smooth-surfaced built-up over ¾" of perlite coverboard over 2" polyisocyanurate insulation on a steel deck in the winter. The season makes a difference with the value of the outside air film. Let’s start from the inside and go out.

Total R-value for the above roof system is 14.54.