The Big Idea
- When a homeowner has a new roof installed over an existing shingle roof instead of tearing the old roof off first, it’s often called a “roof overlay.”
- People often consider overlays because they can cut costs. Since no one needs to tear off the old roof, you pay less for labor and disposal.
- But overlay isn’t always allowed, and more than that, it isn’t always the right choice.
“Can I install a new roof over the old one?” This is a common question we get here at DFW Roofers, and it’s no mystery why. Choosing a roof overlay option lowers the upfront cost of a roof replacement. But a roof overlay isn’t always the best decision. In this guide, we’ll explain when overlays are a good choice and when a full tear-off replacement is better when we consider long-term savings.
Why Homeowners Consider a Roof Overlay
As we discuss in our guide to roof replacement costs[LINK], a standard roof replacement usually includes tear-off, disposal, and cleanup costs. That’s because removing an old roof is pretty laborious, and so is hauling it, dumping it, and then cleaning up the site. This is a significant cost that can be seemingly avoided by installing a new roof on top of the old one. And that’s to say nothing about the benefit to homeowners of a shorter and less noisy repair window.
That’s where the idea of a roof overlay comes from. But there’s a tradeoff worth considering: overlays tend to push costs into the future rather than bypass them completely. After all, when the time comes for the next replacement, you’ll still need to remove both layers, which will increase tear-off and disposal costs simply because there’s more material to remove. So the right way to think about overlay is as an option that can lower the upfront cost, but doesn’t really make tear-off costs disappear forever.
Is It Better to Install a New Roof Over an Old One?
Using roof overlays can be fine in some circumstances, but in others, it can create problems that cost more than the tear-off would have. In most cases, the decision comes down to whether your existing roof is in good enough shape to serve as a base for the new layer. That’s because shingles need to lie flat and seal correctly for a new layer to be successfully installed. If the existing roof is curled[LINK], buckled, or uneven across large areas, the new shingles won’t sit right and this can cause bigger problems down the road.
If those “bigger problems” happen, then you’ll be paying for those plus a possible tear off to fix them. With a tear-off, the contractor crew is able to check the roof deck for soft spots, rot, and other problems and repair them before the new roof goes on, which isn’t possible with an overlay. So, signs of leaking, stains, soft decking, or sagging might not be seen. Homeowners should also consider the amount of detail work the roof needs. Chimneys, wall intersections, skylights, and ventilation need high-quality flashing to avoid leaks[LINK]. So, if the job needs a lot of chimney or wall flashing rebuilds, skylight work, or ventilation changes, a tear-off might be easier and save money in the long run.
We’re Here to Help
Need more information about choosing the right roof or siding? If you have any questions or need assistance with damage, contact DFW Roofers at (469) 751-4018 or schedule an appointment through our online appointment form.
