Roofing over old shingles is usually cheaper up front, but it can hide rotten decking, trap heat, add weight, shorten roof life, and complicate warranties. For most Marietta homes, a full tear-off is the better long-term choice.
Why a roof-over looks attractive
A roof-over skips much of the tear-off labor and disposal cost, so the initial price can be lower. That is why it gets pitched as a budget option.
The problem is that the new shingles are only as good as what is underneath. If the old roof has trapped moisture, uneven shingles, bad flashing, or soft decking, those issues stay hidden.
What can go wrong
- Rotten decking remains covered instead of replaced.
- New shingles sit unevenly over old curled shingles.
- Heat builds up and can shorten shingle life.
- Extra weight is added to the roof structure.
- Future leak diagnosis becomes harder.
- Manufacturer or workmanship warranty terms may be weaker.
Why tear-off is cleaner
A tear-off lets the roofer inspect the entire deck, replace bad sheathing, rebuild flashing details, install underlayment correctly, and start the new roof system from a known surface.
If you plan to stay in the home, the cheaper roof-over can become the expensive option later.