A healthy roof is critical l to your downriver home’s value, curb appeal, and safety. Roofs offer your home its crowing appearance and critical protection against elements like wind, rain, hail, and snow.

As your roof gets older, it may start deteriorating. Your shingles can break down, crack, fall off, curl, or develop other issues, which can lead to leaks. This may allow water to penetrate through the roof and can lead to other ongoing issues such as wood rot, mold, and mildew growth in your home. According to the National Roofing Contractors Association, a roof should be replaced when it starts leaking and when it cannot be simply and easily repaired, or the issues are widespread (meaning they are impacting more than one area of the roof).

While roofs age and lose some of their integrity over time, the majority of the damage done to your roof is caused by external factors like snow, rain, wind, hailstones, tree limbs and other debris, heat, inadequate attic insulation, ice dams, and more.

Some of this damage may not be avoidable, for example, even with the precautions severe weather can damage your roof. However, in general, there are ways to avoid some of the damage to your roof, including

  • Repairing or replacing damaged sections so water does not get in and damage surrounding areas.
  • Trim dead tree limbs surrounding your property to avoid some impacts.
  • Install attic ventilation to help keep the roof cool.
  • Install attic insulation to avoid ice dams.
  • Remove snow and ice from your roof as quickly as possible.
  • Remove moss from your roof when you notice, this prevents trapped moisture.
  • Keep your gutters clean and in good repair.

One of the biggest challenges for experienced builder and novices alike is accurately estimating materials for a construction project–especially for roofs, because they can be challenging to access for taking measurements.

At AllPoint, we offer a free evaluation of your roof and will do all the appropriate measuring. However, if you are looking to measure for yourself, we have some recommendations. Please always remember to keep safety in mind if you are going to be climbing on your roof.

How Shingle Quantities are Measured

It is critical to make sure to take your time and double-check your numbers when calculating the quantity of shingles, underlayment, flashings, and other materials needed for your roofing project. The more accurate your estimates, the less time you will waste waiting for material deliveries during the project if you choose to replace your roof yourself.

Roof shingles are sold by both the bundle and by the square. A square of shingles is the quantity needed to cover 100 sq. ft. of roof. Shingles are packaged in paper or plastic-wrapped bundles that are designed to be light enough for a person to carry, so heavier shingles require more bundles per square. Three bundles to a square is the most common and applies to most three-tab strip shingles and some lightweight laminated shingles. Heavier three-tabbed shingles and laminated shingles require four, or sometimes five, bundles to cover a square. When shingles come three bundles to the square, there are 29 standard-sized shingles (12 in. by 36 in.) in each bundle.

Determining the roof area is the first step to determine how many bundles you will need to order. Once you have a bundle or square count for the primary roof area, you will add additional shingles to account for waste, starter shingles, and extra shingles for hip and ridge caps.

The most accurate way to determine how many bundles of shingles you will need is get up on the roof and measure each roof plane. If all the roof planes are rectangles, all you have to do is multiply the length times the width of each plane to get the square footage and then add up the square footage of each plane. Many times, the roof is too steep to walk on without the proper safety equipment, so you need to do the estimate from the ground. In that case, measure the length of the building at the ground level and estimate any rake-edge overhangs. Then, from a ladder, use a stiff, wide blade measuring tape to measure from the eaves edge to the ridge

Calculating the Area of a Complex Roof

Areas of complex roofs with multiple hips and valleys take a significant amount of time to calculate. Start by making a rough sketch of your roof. To simplify the calculation, divide the sketch into rectangles and right triangles (triangles with one 90-degree corner), then take as many measurements of the roof as you can to match the sides of the rectangles and triangles on the sketch.

Use visual cues from the existing roof shingles or roof sheathing to establish square lines off eaves edges or ridges. These cues will assist you as you measure the lengths of the sides of the rectangles and triangles. For example, the cutout slots on shingled roofs run perpendicular (90 degrees) to the eaves, and nail rows in sheathing are pretty close to square also. It is difficult sometimes to get accurate measurements. Do not get too concerned though; just round lengths to the nearest 6 in.

With the sketch filled in with measurements, you can ascertain the size of the roof area. The area of a rectangle is length multiplied by width, while the area of a right triangle is the length of the two sides that meet at the 90-degree corner multiplied together and divided by two (this works because a right triangle is half a rectangle).

Calculate the square footages of all the rectangles and triangles, which will give you the total square footage for the roof.

Your roof is one of the most important structural elements of your house, and in order to complete a successful roofing project a substantial investment in both time and money is required. We highly recommend you hire a professional like AllPoint for roofing work, as it can be difficult to cover the costs of pricey mistakes. If you are undertaking the project yourself, it is critical to remember roof work can be a risky and potentially dangerous job. Anything you can do take less trips up and down the ladder to the roof lessens the chance of injury.