ELEMENTS OF A PREMIUM ROOF – ICE AND WATER SHIELD
ELEMENTS OF A PREMIUM ROOF – ICE AND WATER SHIELD
A premium roof not only uses superior, high value materials, but must also be installed according to the best roofing practices, manufacturer specifications, and take into account the overall aesthetics of your home. A well applied, top-of-the-line system will give you the long-term protection you need, and enhance both the pleasure you get from your home and its resale value.
In order to better understand what makes up a premium roof, it may be helpful to become familiar with some of the terminology that is commonly used in the roofing industry.
The deck is your roof’s foundation. To have a solid foundation, a strong deck is a must. Plywood or roof board are the most common materials used to form the deck. For plywood, the materials should be at least ½ inch thick. Any part of the deck that is rotten or warped must be replaced.
Considerable damage can be caused to the lower edges of the roof and the eavestroughs as a result of ice dams (ice build-up during winter freeze/thaw cycles). A specialized, modified bitumen sheet (better known as an ice & water shield), should be used at a minimum of three feet up from the eaves.
With high winds and driving rains, water can get trapped under the shingles. An extra layer of protection is required to ensure the maximum lifespan of the roof and its components. A high-quality underlayment (also known as “paper” or “felt”) should begin after the ice & water shield and cover the remainder of the deck.
The valley, commonly made of pre-painted, galvanized sheet metal, is usually found where two slopes of a roof meet. This is a spot where snow and ice can build up, especially on roofs with lower pitches. Thats when valley flashing installation comes into picture. An ice & water membrane should also be installed at the metal valley flashing.
For efficient water shedding at the roof’s edge, and to keep water from penetrating or staining the fascia, metal drip edges should be installed along the rakes and eaves. The metal drip edge should be positioned under the ice & water shield at the eaves edge, and over the underlayment at the rake, to better direct water into the troughs.
The flashings are one of the most common sites where leaks occur. Flashing is located where roof planes intersect, around vents, skylights, or at the chimney. All flashing systems should be fixed so as to direct water over the joint, not onto or into it. A flashing system that is properly and neatly installed will allow water to run smoothly over joints, and decrease the chance of roof leakage.
Shingles are not waterproof – they are designed to shed water away from the roof and into the eaves for drainage. In order to get the maximum performance out of your shingles, all other roof components must be carefully chosen and properly installed. Premium asphalt shingles that consist of heavy-duty felt, fiberglass or laminate mats, and thicker granule coatings, last longer and come with higher warranties. Making the investment in a premium shingle is a wise choice, as the added cost is minimal when compared to the overall cost of prematurely redoing the entire roof.
Ventilation is arguably the most important component of your roofing system, and one that is often overlooked. A properly ventilated attic will keep your roof deck and insulation dry, dissipate heat build-up, and extend the life of your shingles. Having proper levels of ventilation will also help ease your heating and cooling costs. Ventilation should be split into two pathways: intake though perforated soffits, and exhaust vents, which should be placed near the top ridge of your roof. There are a number of different venting options available, so be sure to have your roofing professional highlight those that best suit your property.
Should I put ice and water shield on my entire roof?
It is rarely necessary to use an ice and water shield on your entire roof. When you do need to use one it should cover a minimum of 3 meters up from your eaves. If more of your roof´s surface needs to be covered, we will advise you of that fact and explain why it is necessary.
How long can you leave ice and water shield exposed?
How long an ice and water shield can be exposed varies. It depends on the manufacturer´s recommendations, the materials used to make the shield and local weather conditions. In most cases, it will be fine if left exposed for 30 days. But some types can withstand being left uncovered for up to 90 days.
Does Ice and Water Shield go under drip edge?
The ice and water shield should go under the drip edge. Installing it that way ensures that windblown rain runs over the underlay rather than the sheathing. This is better for the long-term integrity of the roof. It is also a good idea because most manufacturers do not recommend that their ice and water shield be left exposed.