Choosing between an overlay and a tear-off for modified bitumen roofing often depends on the roof's current condition and the long-term goals for your home. An overlay involves installing a new modified bitumen layer directly over the existing roof. This approach is typically faster and less expensive since you avoid the labor and disposal costs of removing the old layer. However, overlays can only be done if the existing roof is in relatively good shape—there shouldn’t be extensive damage, leaks, or multiple layers already present. You can do a simple DIY check by walking on the roof carefully (if safe and permissible) to feel for soft spots, blistering, or obvious damage. Look inside the attic for any signs of leaks or moisture, which may indicate underlying issues. If you find these problems or if the current roof has more than one or two layers of material, a tear-off is usually the safer option.
A complete tear-off removes the old modified bitumen down to the deck, allowing contractors to fully inspect and repair the substrate before installing a new roofing system. This option is more costly and time-consuming but offers the best long-term protection and warranty coverage. When calling a roofer, ask specific questions like: “How many layers of modified bitumen are currently on the roof?” and “Will a tear-off help prevent hidden moisture or structural issues?” These questions encourage the contractor to assess the roof comprehensively rather than rushing into an overlay. Proper diagnostics and a clear warranty understanding can save you from future problems, so opting for a contractor who explains the reasons behind their recommendation is key to making a confident choice between overlay and tear-off.