Roofing Rules

Remember two simple codes for new shingles.
By: Dwight Barnett

Q: I'm having new shingles installed on my home in upper New York State. Looking at the estimate, I could not find a price for the roof paper. The roofer said that paper is not required for the new shingles. I thought it was required by code.

A: For an answer about codes, contact your local building officials. Because of geophysical and climatic differences, state or local codes can vary.

Prior to the 2000 International Residential Code (IRC), most codes were taken from the various trade groups, such as the National Electrical code, the National Mechanical code and the Uniform Plumbing code, I consulted the 2000 IRC's Section R905 "Requirements for Roof Coverings."

There, under asphalt shingles, I found requirements for the number and size of nails to be used, when to use an ice shield, where to place flashings, how to install shingles in regions with high winds and on and on.

There are two simple codes to remember for new shingles:

  • First, the shingles must be delivered in packages "bearing the manufacturer's identifying marks and approved testing agency labels."
  • Second, the roof shingles, "shall be applied" in accordance with the manufacturer's installation instructions. Every package of shingles I have ever seen has the installation. The instructions are usually printed on each bundle.
    Felt paper is required under the new shingles. Insist that the roof shingles be installed to the standards listed on the shingles.

Other common shortcuts your roofer should avoid:

  • Do not shingle over wet or damp roof sheathing or damp felt paper. The trapped moisture cannot evaporate when the sun heats the shingle.
  • If you plan to stay in the home for the next 10 years, do not shingle over older shingles. The general rule, not a code, is to use only one layer of shingles for low-sloped roofs, possibly two layers for medium-sloped roofs and up to, but never exceeding, three layers of shingles on a steep-sloped roof. Stripping away the old shingles will cost more, but the new roof covering will last longer if it is a single layer.
  • It is easier and cheaper to use a shingle material for flashings, but they don't have the same elasticity or life expectancy. Use metal flashings where the shingles butt up to a wall, chimney or skylight.
  • Do not use caulking, roof tar or asphalt mixes to cover flashing materials. Use counter flashings made from the same metals as the flashing. Install new boots on plumbing vent stacks.
  • Use similar roof sheathing materials — i.e., plywood or three-quarter-inch lumber — to repair holes that might be discovered in the original sheathing when the shingles are removed.

(Dwight Barnett is a certified master inspector with the American Society of Home Inspectors.)

Next Up

Top 6 Roofing Materials

From wood shake to asphalt shingles, roofing material is an important consideration that contributes to the overall look and style of your home.

Roofing Needs Require Some Math

To determine the pitch of the roof, measure over on a level line 12 inches from the edge of the roof on any part of the roof and measure vertically to see what the rise is.

Roofing Component Basics

Roofing terminology can be a bit overwhelming. These basic roofing definitions will help get your project off on the right foot.

The Benefits of Synthetic Slate Shingles

They're more durable, easier to install and much less expensive than authentic slate.

Repairing Roof Damage

A homeowner wants to know the cost of repairing a hole caused by moisture from a damaged roof.

How to Replace Ridge-Cap Shingles

Keep rain and melting snow from leaking inside with three simple steps.

Maximum Value Home Exterior Projects: Roof

Learn how the roof of your home can attract or detract from its selling potential and how improving it can add value to your home.

Weekend Project: How to Add Architectural Design to a Roof Gable

Add interest to your home's exterior by adding a traditional-style accent to a plain gable. It takes less than a weekend to build and costs less than $100 in materials.

Weatherproofing the Roof

Peel-and-stick underlayments provide years of protection.

Designing a Roof Addition

Consider these four options so the new portion of your roof matches the original one

Go Shopping

Get product recommendations from HGTV editors, plus can’t-miss sales and deals.


House Hunters

1pm | 12c

House Hunters

1:30pm | 12:30c

House Hunters

2:30pm | 1:30c

House Hunters

3:30pm | 2:30c

House Hunters

4:30pm | 3:30c

House Hunters

5:30pm | 4:30c

House Hunters

6:30pm | 5:30c

House Hunters

7:30pm | 6:30c
On Tonight
On Tonight
8pm | 7c
8:30pm | 7:30c

House Hunters

11pm | 10c

House Hunters

11:31pm | 10:31c

House Hunters

2:31am | 1:31c
3am | 2c
3:30am | 2:30c

House Hunters

4:30am | 3:30c

House Hunters

5:30am | 4:30c

Follow Us Everywhere

Join the party! Don't miss HGTV in your favorite social media feeds.