A metal roof can sometimes be installed over asphalt shingles, but it is not always the best choice. Tear-off lets the roofer inspect decking, fix ventilation, correct flashing, and avoid trapping old roof problems under an expensive new metal system.
Why homeowners ask about metal over shingles
Skipping tear-off can reduce labor and disposal cost, so it looks attractive. It can also shorten the project timeline.
The tradeoff is that you are putting a long-life metal roof over an old roof system you may not fully understand.
Problems that can get trapped underneath
- Rotted or soft decking that cannot be seen from above.
- Old leak paths around chimneys, skylights, valleys, or pipe boots.
- Poor attic ventilation that shortened the old shingle roof's life.
- Uneven curled shingles telegraphing through the new assembly.
- Extra weight from multiple existing layers.
When tear-off is usually smarter
If the asphalt roof is leaking, old, brittle, curled, soft, or already has more than one layer, tear-off is usually the better choice.
For a premium standing seam roof, Rhino typically prefers starting from a clean deck because the details under metal matter for decades.
What to ask before approving it
- How many shingle layers are already on the roof?
- Will the contractor inspect attic decking from underneath?
- What underlayment or slip sheet goes between shingles and metal?
- How will flashing, penetrations, and ventilation be corrected?
- Will the manufacturer warranty allow this installation method?