Which parts of the roof are due, at altitude and under a nightly freeze

A roof is several parts on several clocks, and here the south face can run through its clock years ahead of the north. Enter when the house was built and what has been replaced since, and it will show where each part stands.

Use this to decide where to look, not to decide the job. It sets ages against the service lives the trade generally expects. Along the Front Range a south slope over a hot attic can wear out well ahead of the range, and a roof over a well-vented attic on a north slope can outlast the range comfortably. The weather counts for more than the calendar.

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Set the house, then set what has been replaced

When was the house built? What is on the roof now?

What has already been replaced?

Keep a row at Original if that part was never replaced, or if a previous owner may have done it and the invoice did not come with the house. Unknown is a normal answer here.

Roof covering Flashing at walls, valleys and penetrations Underlayment and ice-and-water shield Gutters and downspouts Attic ventilation Skylights (if you have them) Chimney crown, cap and masonry (if you have them) Fascia and soffit Siding or exterior cladding Window seals

A roof rarely wears out evenly. It goes at the joints, and on the sunny side. Which is why flashing, not shingle, is the item most worth knowing the age of.

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1 Ridge caps. Worked loose by a temperature swing that happens every single day.
2 The field. High-altitude sun dries the covering out from above, faster than the calendar says.
3 Valleys. Where two slopes drain as one, and where meltwater runs longest.
4 Flashing. Chimney joints, and the line where the garage roof meets the house.
5 The vent boot. Rubber cracks early at this altitude, well before the shingles do.
6 Eaves. Ice builds at the edge wherever the attic is leaking heat into the roof.

Why new shingle can sit on an old roof

On a quick re-roof the shingle is usually replaced and much of what surrounds it is not. Flashing is sealed, vents go back on, the underlayment may or may not be pulled. The surface resets; the parts around it keep their age. That is why this page asks about underlayment and flashing on their own lines, and why on many houses the honest answer is that nobody knows what was left under the last job.

Flashing is the clearest case. Sealing the old metal at the chimney is faster than replacing it, and it is done often enough that a roof put on five years ago can be relying on flashing from thirty years ago. If someone tells you the roof is new, the useful question is what the invoice actually covered.

Use this page

Copy or link to this freely, crediting frontrangeroofworks.com. If it helps someone in Westminster or Littleton work out what the last roofer replaced and what it did not, it has done its job.

Quotes already coming in? The quote comparison lays three of them out side by side, row against row.