When To Replace a Roof

If you are like most people, you probably would prefer to postpone roof placement as long as possible.   However in Portland, Oregon, with our seemingly constant rain, waiting too long to replace your roof can present a whole list of problems.   So as much as you might prefer to answer the question, “When should I take my next vacation?” let’s take a moment and review some signs that is might be time to replace your roof.

Without even inspecting your roof and home, one of the first things to review is the known age of the roof.   This simple piece of information can help you determine the possible urgency of the evaluation.   In the Portland area, even a low end roof should last 15-20 years.   More commonly, medium quality, periodically maintained composition and cedar roofs should last 25 to 35 years.   Top quality composition, cedar roof along with tile roofs can easily last well beyond 40 years.

While there is always the possibility of an improper installation, a material defect or storm damage, knowing the age of your roof helps take some of the mystery out of the process.

Next, let’s review some obvious warning signs of the need to replace your roof.

Spots on the ceiling



A ceiling leak can indicate time to replace your roof.

A ceiling leak can indicate time to replace your roof.



Without even going roof top you may be able to ascertain some clues.   Every year, we talk with an amazingly large number of people who have seen small discolored spots or some chalking and flaking of drywall without experiencing a full blown leak.  Whether it is like a spigot turned or no water at all and just discoloration, you need to investigate internally and externally.   Look for the following:

  • Sagging ceiling material
  • Wet or darkened wood in the attic
  • Nearby rafters or internal structures which sometime might channel leaks away from their original source.
  • Any excessively rusted nails that might be poking through the sheathing.
  • If you don’t have attic space but rather have a catherdral type ceiling, it is even more critical to scrutinize discoloration on the ceiling material


Roof Top Review

Start with with shingles or shakes in the field of the roof (the main sections of the roof’s body.)

Loose granules (shingle roofs)

Severe Granule Loss

Granule loss is a primary sign of needing to replace a roof

Immediately after installation and again near the end of it’s life, shingle roof’s loose granules.   When a roof is old and due for replacement, the granule loss can be significant.   Once the UV protection wears aware, the granule loss can be very fast.   This in turn exposed either the asphalt or fiberglass composition base of the shingle which then starts to deteriorate all the faster.   It becomes a viscous deterioration process that needs prompt attention.   Sneaking a peak in the gutters can give you a quick view of how much granule has come down since the last gutter cleaning.   We recently cleaned out the gutters on a home that had such bad granule loss that when we put a garden hose with virtually no pressure on the roof after right after rinsing the gutters, a steady flow of new granules flowed down and coated the bottom of the gutter.   Such a roof should be replaced within six to twelve months at the very latest.

Burn through (cedar roofs)

While cedar roofs have no granules, they have plenty of fiber.   This fiber is subject to deterioration from both the UV rays and from excessive and unskilled power washing.   If you spot any shakes that have a con-caved shape, especially with a deep dip in the middle with even possibly a small hole starting in the middle, you have burn through.   At a minimum you need some shakes replaced.   If too many shakes are like this and the underlying felt has been exposed to the sun for too long, you need to re-roof.

Missing Shingles or Shakes:

This really goes without saying – if shingles or shakes are missing, that is an ominous sign.

Dips or Up Buckling:

Dips often are a sign of rot occurring in the underlying sheathing while buckling can indicate that moisture underneath the roof (never a good thing) has caused it to swell and lift up.   Shingles like a flat, smooth surface for maximum life and start to crack when the underlying surface becomes uneven.


Unless lifted by moss growing at the butt (front) end of the shingle (which will typically lay back down over time once the moss is removed), curling mean that the shingle has no more life left.   Often these shingle have been cooked from the underside due to inadequate attic ventilation (see my post below on attic ventilation.)   If a cedar shake is curling, do NOT nail it back down – it will either crack off or if not, you will be left with exposed nails.   A curled cedar shake has lost it’s battle against the UV rays and no longer drains rainwater properly.


Another likely sign of moisture entry.

Exposed Fasteners:

There are always a few spots on a roof where nails can’t be hidden under the course above it.   These should be installed using self sealing roofing nails.   If you see nail heads exposed or surfacing (lifting up) through shingles, they are likely being forced up from interior moisture.   Run, don’t walk, to the phone and call a roofer.

Damaged Roof Flashing & Vents:

Don’t be too quick to assume that if there are issues with flashing it means you need to replace your roof.  Maybe or maybe not.   Sometimes these items rust through or get knocked or wiggled out of place on a roof that still has plenty of life left.

Of all the flashing issues that can occur, chimney flashing problems are the most serious and the most difficult to repair.  Look for cracks or sections that have become dislodged from their connection with the chimney, particularly if the chimney is masonry.   Also, you can be fooled by a chimney leak.   Sometimes it is the flashing around the chimney while other times, it may be the chimney itself (ie, top caps, cracked bricks or saturated brick in need of resealing.)  If that is suspected, call in a chimney mason in addition to a roofer.

Flashing where a lower roof meets an upper story wall is called roof-to-wall flashing.  Review for rust, cracks or misalignment.   Drip and rake flashing are at the roof edges.   This commonly may dislodge so look for misaligned or even completely missing flashing.   Any flashing problem can allow moisture entry into an otherwise good roof and risk accelerating the need to replace the roof.

When the result is the need to replace the roof.

Remember that roofing is not a service that just anyone should do for you.   Reputation and integrity matter every bit as much if not more than price.   Don’t fall into the trap of thinking since you plan to only be in the house a few more years that it doesn’t matter if it is a quality job.   Plans change and a lot can go wrong with a low quality installation within just a couple of years.   Call a roofing contractor you can trust today – 503-570-7663.