Photograph of  really worn out asphalt roof shingles Asphalt Roll Roofing Installation, Defects, Repairs

  • ROLL ROOFING, ASPHALT - CONTENTS: Asphalt based roll roofing installation, inspection, leaks, life expectancy. Definition of roll roofing materials, specifications, standards, applications. How and where should mineral granule coated roll roofing be used on buildings? What is the life expectancy of roll roofing
  • ASPHALT ROOF SHINGLES - separate article, same material
  • POST a QUESTION or READ FAQs about roll roofing

Roll roofing installation, inspection, troubleshooting, repairs: this article describes mineral-granule coated asphalt roll roofing roofing materials, choices, installations, inspection, defects, roofing repairs, and product sources. Our page top photo shows our client pointing to a low slope area on a roof where mineral-granule coated asphalt roll roofing was applied after shingles in that location had leaked repeatedly. Because mineral-granule-coated modified bitumen roofing can be mistaken for roll roofing, and vice versa, readers should also see MODIFIED BITUMEN ROOFING.

Green links show where you are. © Copyright 2015, All Rights Reserved.

Asphalt Roll Roofing Materials, Choices, Costs, Life Expectancy, Characteristics

Roll roofing material (C) Daniel FriedmanAs stated in Best Practices Guide to Residential Construction, chapter on BEST ROOFING PRACTICES:

Roll roofing is simplest product to install on a small section of lowslope roof is 90-pound roll roofing.

This consists of a heavy, asphalt-saturated organic or fiberglass felt with a granular surface. Rolls are 36 inches wide and weigh 90 pounds. Single-coverage roll roofing typically has a 2-inch lap with exposed nails and is used mainly on utility structures.

Double-coverage roll roofing is installed with a full 19-inch lap joint, leaving a 17-inch exposure, with a 2-inch head-lap.

Nails are concealed under the lap joints that are sealed with asphalt lap cement. With two layers of protection, double-coverage roll roofing is acceptable for small roof areas and can be used on roofs as shallow as 1:12.

-- Adapted with permission from Best Practices Guide to Residential Construction.

In its earliest forms roll roofing consisted of sheets of felt canvas or cloth that were impregnated with asphalt, then rolled flat along a low-slope or even some steeper sloped roofs with the material's long edge parallel to the building eaves.

Modern 90-pound asphalt roll roofing is built of mineral-coated fiberglass-reinforced mat or organic-mat (bituminous impregnated paper) material very similar to asphalt roof shingles, in 36-inch wide material sold in 36-foot long rolls. Roll roofing is coated on both sides with asphalt and its upper or exposed side is protected with mineral granules.

Common roll roofing material colors are white, brown, black. You may find some roofers referring to roll roofing as "90-pound felt" since a 36-foot roll of the material, able to cover about 100 sq.ft. (one roofing "square") weighs close to ninety pounds.

Tips For Buying Roll Roofing Materials

Our roll roofing material photo (left) shows that this roll was a bit out of round. When buying roll roofing avoid rolls that are squashed as they may be difficult to roll out smoothly (give the material time to relax and flatten before nailing).

Also avoid rolls whose ends are badly damaged as it may make for uneven or raised seams.

This is an inexpensive roofing material often installed (over 15# felt underlayment) by homeowners and do-it-yourself-ers.

Installing Roll Roofing for Maximum Life

Roll Roofing Problems (C) Carson Dunlop AssociatesNonetheless roll roofing installations will have a longer life if installed according to the product manufacturer's instructions, nailed at proper intervals, and with seams properly sealed.

It's also important to install roll roofing over a smooth sound roof deck. If the roof decking sags, ponding on the roof surface after rain may reduce its life.

Overlapping strips of asphalt roll roofing are installed over the roof surfaces with overlapped edge joints sealed, usually with a heated asphalt compound, or cold-applied using a similar sealant that functions at lower temperatures.

Sketch (left) courtesy of Carson Dunlop Associates.

Probably in part because asphalt roll roofing is typically used on low slope and nearly flat roofs, it can have an anticipated wear life of less than ten years, often five years.

The life of roll roofing may be extended by coatings.

Common Problems on Roll-Roofing Covered Roofs

Roll Roofing Problems (C) Carson Dunlop AssociatesAs Carson Dunlop's sketch (at left) illustrates,

  • A common roll roofing problem includes wrinkles or bubbles.
  • Granule loss and exposure of "bald spots" or cracking are common signs that roll roofing is at the end of its life

Not quite so common, but we also see misapplications of roll roofing such as:

  • Running the roll roofing over a 90-degree angle and up the vertical surface of a parapet wall or chimney as "flashing"
  • Running roll roofing with its seams parallel to the building gable ends

More Reading

Green link shows where you are in this article series.


Frequently Asked Questions (FAQs) about roll roofing


Ask a Question or Search InspectApedia

Questions & answers or comments about roll roofing installation, life, leaks, repairs..

Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.

Technical Reviewers & References

Publisher's Google+ Page by Daniel Friedman

Click to Show or Hide Citations & References