Should you replace the roof and siding at the same time?
Short answer. Doing both together can make sense, especially after a hailstorm that damaged both, but the roof should go first or the two crews must coordinate the roof-to-wall flashing. Step flashing, kickout flashing and the trim where roof meets wall are shared details that leak when neither trade owns them.
Order of work
- Roof first. Tear-off drops debris down the walls, and the roofer installs step flashing and kickout flashing against the wall sheathing.
- Siding second. The siding crew installs house wrap and siding over the vertical legs of the step flashing, so water stays on the outside of every layer.
- Gutters last, once fascia and trim are finished.
If the siding goes on first, the roofer either has to cut into new siding to replace flashing or reuse old flashing behind it, which is a common source of leaks.
The details where they meet
- Step flashing at every sidewall, one piece per shingle course.
- Kickout flashing at the bottom of each roof-to-wall joint, steering water into the gutter instead of behind the siding.
- Clearance between the siding and the shingle surface, per the siding maker's instructions, so the siding does not wick water.
After a storm
Hail that bruises shingles often cracks vinyl siding, dents aluminum and chips paint. Document everything at once, because the claim covers the whole house, not just the roof. Coverage depends on your policy, and matching on siding is its own conversation with the adjuster.
Who does what
Get each contractor's scope in writing, including who supplies and installs the kickout flashing, and schedule the siding crew to start after the roof passes its final check. Read roof flashing explained and common roof leak causes for why wall joints fail.