What is likely due on your roof, and what is not

Most of what keeps water out of a house has a working life measured in decades, and the components rarely reach the end of it together. Tell it when the house was built and what has already been done, and it will show you where each part sits.

This is not an inspection and not a prediction. It compares ages against service-life ranges that are widely used in the trade. A roof can fail at twelve years or last past thirty. Exposure, ventilation and how it was installed matter more than the calendar. Use it to decide what to look at, not what to buy.

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Roof age check

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

What has already been replaced?

Leave a row as Original if it has never been done, or if it was done before you owned the house and you have no record of it.

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 here rarely gives out in the field. It gives out where the water is told to leave. Which is why flashing, not shingle, is the item most worth knowing the age of.

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1 The ridge. The highest, hottest course, and the one the sun works on all day.
2 The field. Tile or shingle above, and the underlayment that actually keeps water out below.
3 Valleys. One channel carrying what two slopes shed, at the pace this coast rains.
4 Flashing. Where the lanai and the enclosure meet the house, and where neither trade owns the seam.
5 Penetrations. Every vent and curb is a hole the underlayment has to seal, and the first place it stops.
6 Eaves and metal. Drip edge and fasteners, which salt air reaches years before it touches the covering.

Why the age of the shingle is not the age of the roof

A replacement laid over an existing layer leaves the old underlayment in place. The visible surface resets; the second line of defence does not. That is why the tool asks about underlayment separately, and why the honest answer for many houses is that nobody knows. The record of the last tear-off has usually been lost.

The same applies to flashing. Re-using and sealing the existing metal is faster and cheaper on the day, and it is common enough that a roof installed five years ago can be carrying flashing installed thirty years ago. If you are told a roof is recent, the useful follow-up is whether the flashing is recent too.

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This tool may be reproduced or linked to freely, with attribution to calusaroofing.com. If it is useful to a homeowners association, a housing counsellor or a community group, it is meant to be shared.

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