Portland Roofing Contractor

While the workmanship warranty and job agreement (outlined in part one) can be negotiated, the manufacturer’s warranty is set in stone. There’s nothing you or your roofing contractor can do to adjust it– it’s fixed and it’s limited. Therefore, it is very important that both you and your roofer understand each term and condition.

A manufacturer’s warranty on asphalt shingles, for example, will typically address:

  • Methods of installation
  • Finished system performance
  • Finished job appearance
  • Warranty transferability

Possibly the biggest factor in a homeowner’s satisfaction with a new roof is its overall finished appearance. System performance is also important, of course, but these days much of that relies on the quality of workmanship rather than the materials themselves. On the other hand, a new roof can sometimes look a bit different that you expected it to when you were looking at samples, and that can lead to claims against the manufacturer’s warranty. The appearance of a finished roof can be affected by a number of variables including color, staining, patterns, decking issues, and damage.


We try to warn homeowners against hanging all their expectations on product samples and color specifications they see in print. Shingle color is not an exact science even though they are computer controlled. It can vary to the eye according to the time of day and the weather, and change as the shingles get older. This is often because the position of granules on the shingles can create tiny shadows, and then those granules tend to wear away with time. Because of this, many manufacturers simply exclude color variations from their warranties.


New shingles can sometimes become stained while still in the packaging when oils or minerals get transferred from the underside of one shingle to the face of another. In most cases, once the shingles are installed natural weathering will wash away these stains. But, if the stains are still visible after 60 days be sure to contact the manufacturer.

The most common type of stain you’ll see on older roofs is caused by algae, which people often confuse with mold or fungus. Unless algae-resistant shingles were used, algae stains will not be covered by the manufacturer’s warranty as it is a symptom of poor maintenance on the homeowner’s part. Warranty terms regarding algae-resistant shingles vary by manufacturer.

Ugly Patterns

When shingles are not installed according to the manufacturer’s instructions, strange color patterns can appear. An inexperienced or unethical roofer might misalign shingle cut outs or ignore dimensional tolerances. Because of this, manufacturer warranties disclaim liability for improper installation.

Deck Movement or Failure

A new roof can also become unsightly if there are problems with the decking. If the surface that the shingles are nailed to begins to shift or fails altogether, which can can be caused by inadequate ventilation, poor nailing of the deck and other oversights, the shingles can curl or develop objectionable ridges. These problems are excluded from warranty coverage by all shingle manufacturers.


Anytime you add on to your home or do any remodeling like installing a skylight, your roof is susceptible to damage. This is never covered by the manufacturer’s warranty. So, when work is being done on your home, make sure to schedule the roofing work so that it won’t be affected by other projects or workers.

Furthermore, shingle damage caused by a homeowner’s efforts to remove snow and ice is typically excluded, as is damage caused by aftermarket coatings, paints, chemicals, and cleaners.

Have more questions about the warranty on your roof? Click here to ask Stan, or call 503-635-8706.


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Portland Roofing Contractor Since 1980

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