What each one actually does
A replacement removes the shingles and the underlayment beneath them and builds the roof again. It is a multi-day job with a tear-off, a dumpster and a crew on the property, and it is priced as a construction project.
A treatment works on the shingles that are already there. The surface is cleaned, the treatment is applied so it works into the shingle, and the work is done in about two hours in a single visit.
The decision is condition, not age
Two roofs of the same age can be in very different condition, so age is a poor way to choose. The Roof Health Score measured at the assessment is what separates the two paths: Good or Fair takes a UV shield, Aging takes a restorative treatment, Low or Critical takes a bridge.
Below 21 the honest answer is replacement, and we say so at the visit rather than sell a treatment that cannot hold.
- Still holding water out, surface dull or drying: treatment
- Leaking, soft spots, missing shingles: repair first, then re-assess
- Scored below 21: replacement, with a short bridge if time is needed
- Metal roof: not eligible for this treatment at all
What you keep with a treatment
The roof you have: same shingles, same colour, same profile. Nothing is torn off, there is no waste to landfill from your roof, and the landscaping below the work area stays as it is.
You also keep the day: one short visit rather than days of work, and no dumpster in the driveway.
What the warranty does, and does not, replace
A treatment carries a formal written warranty, from 20 years on the top Fortify Elite row plus 5 years of hail, down to the short prorated bridge. What it covers is failure the treatment is responsible for, not the roof in general.
A replacement, by contrast, is new roof material. That is a much larger promise, and a much larger price. A treatment does not pretend to be the same thing.
How to compare them properly
Get the treatment estimate and the replacement quote side by side, with the term, the coverage type and the value per square foot named on the treatment side. That is the only comparison that uses your roof.
If the treatment is not right for your roof, the estimate will say so, and the visit costs nothing either way.