Measuring, Estimating, and Choosing Roofing Materials

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There are many products in a roof assembly, so choose a system that is specifically designed to work together


Iko Roofing's Jeff Williams hosts this video on how to calculate the amount of each roofing product you will need, but also on choosing among various options within categories.



Hi, I’m Jeff Williams, and I'm your host today on IKO TV. We’re back with the next installment in our series; how to measure and estimate the materials needed for your next job.

Calculations for the square footage of the roofing surface can be made by simply adding up the areas of the various roof sections.

The sum of the total area is then divided by the coverage of each bundle of shingles. Typically, an average 3-tab bundle covers 32.3 square feet, while our architectural shingle bundles vary between 20 and 33.3 square feet. It is advisable to add ten to fifteen percent to this area for material waste or loss based on your roof style.

When using underlayment, the square measure of the roof may be used again to determine the number of rolls of underlayment required.  We recommend our Number 15 Plain Asphalt Felt or RoofGard-Cool Grey™ synthetic underlayment for this job.

Drip Edging requirements are determined by measuring the lengths of the eaves and rake edges.  An open metal valley flashing is recommended for the protection of valley areas.  Depending on the roof design and the shingle chosen, closed cut and woven valleys may also be acceptable.

A pitch finder tool can also be used to measure the slope of the roof. You can determine the roof area by measuring the horizontal area of the roof or attic floor and then multiplying by a factor that compensates for the slope of the roof.

For ice dam protection along the eaves (or anywhere that is susceptible to water penetration), you’ll need ArmourGard™ Ice & Water Protector, or StormShield® Ice and Water Protector.  Asphalt plastic cement is used to seal at vents, stacks, or chimneys.

Galvanized roofing nails are the best fastener to use for roofing, and they should be long enough to penetrate through the shingles and into the deck approximately ¾ of an inch and through the deck if it is plywood or OSB. Nails no less than ¼ inch longer will be required for capping the hips and ridges.

IKO recommends our PRO4™ Roofing System. Shingles alone are sometimes not enough to protect your home. IKO has developed a superior, multi-layered roofing system incorporating our industry-leading products. IKO’s PRO4 Roofing System is setting the standard in protecting your home.

IKO shingles: Crowne Slate™, Royal Estate™, Cambridge™ and Marathon™ Shingles are created using the industry’s most advanced technology, and selected by consumers who demand the best in quality, durability, and value. Along with one of IKO’s quality shingles, your PRO4 system includes one of these accessory products:

  1. Eave protection – ArmourGard or StormShield Ice and Water Protectors—IKO’s ice and water protectors provide a second line of defense against water penetration due to ice dams or wind-driven rain and the costly damage it can cause. This product is strongly recommended for sealing around vents, low-pitch areas, ridges, hips, rake edges, chimneys, dormers, vent stacks and skylights.
  1. Underlayment – Asphalt saturated felt or Roofgard Cool Grey underlayments—Use an asphalt saturated roof underlayment or our innovative Roofgard Cool Grey synthetic underlayment for total deck protection.
  1. Roof Starters – Leading Edge Plus™ Starter Strips—Fast easy and convenient, IKO starter strips are already cut to size saving valuable time during the installation of the first course of shingles. Compatible with all existing IKO shingles, Leading Edge Plus includes a sealing strip at the bottom edge, allowing for a tight seal.
  1. Ridge Cap Shingles – Hip and Ridge Plus™, Hip and Ridge 12™ cap shingles and Ultra HP® high-profile ridge cap shingles—Ridge cap shingles are required where roof planes meet and provide additional protection along these high-stress areas of the roof, enhancing your home’s aesthetic appeal by accentuating the roofline.

You’ve measured your roof and estimated the materials. In our next episode, we'll cover the tools and techniques to tackle the job. Until then, I’m Jeff Williams and we’ll see you next time on IKO TV.


—This video is provided by IKO Roofing, one of ProTradeCraft's advertisers. IKO is a worldwide leader in the roofing, waterproofing and insulation industry for residential and commercial markets. A vertically integrated company, IKO operates more than 25 manufacturing plants throughout North America and Europe. IKO is a family-owned business established in 1951. View all of IKO's content.


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