June 20, 2026 · 7 min read
They meet at the same line
The drip edge, the starter course, the underlayment and the top of the eavestrough all come together in the same few inches at the roof edge. That line is where most eave leaks start, and it is far easier to get right when both the roof and the trough are being handled at once.
Replacing shingles and leaving old trough in place means working around it, and it means the new drip edge has to be tucked into whatever alignment the existing gutter happens to have.
The cost argument
Doing both together is cheaper than doing them separately. One mobilisation, one set of staging and access, one disposal run and one crew on site. The saving is real and it shows up as a lower combined price rather than a discount line.
Splitting the work also means paying twice for access on a two-storey house, which is a meaningful part of any exterior quote.
When you should replace both
The trough is the same age as the roof and has never been replaced. It sags, holds water, or leaks at corners. The fascia behind it needs attention. You have had overflow problems and the system needs resizing anyway.
Also when you are changing shingle profile in a way that alters how water leaves the roof, or adding roof area that the existing trough was never sized for.
When to keep what you have
If the eavestrough is seamless, correctly sloped, properly sized and less than about ten years old, there is no reason to tear it off. We will detach and reset what needs resetting to install the drip edge properly, and leave the rest alone.
A contractor who insists on replacing sound trough as a condition of the roof job is selling, not advising. Ask them to show you what is wrong with it.
Get it priced both ways
The useful thing is a quote that shows the roof alone, the trough alone and the two together. Then the decision is yours with the actual numbers in front of you rather than a recommendation you have to take on trust.
That is how we write it: roof replacement and eavestrough as separate itemized figures, with the combined price shown so you can see the difference.