When deciding between an overlay and a tear-off for SPF (spray polyurethane foam) roofing, it’s important to understand what each process involves and when one might be more appropriate than the other. An overlay means applying a new layer of foam over the existing SPF roof, while a tear-off requires removing the old foam completely before installing a new layer. Overlays are generally quicker, less expensive, and produce less waste, but they are only advisable if the existing foam is in relatively good condition—firm, without significant delamination, water intrusion, or damage. Problems like soft spots, saturation, or cracks usually mean a tear-off is necessary because simply topping a compromised base won’t fix underlying issues and can void warranties. You can perform a simple DIY check by walking on the roof with care; soft, spongy areas indicate saturated foam. Also, visually inspect for cracks or splits. If the roof feels firm and the foam looks intact, an overlay might be feasible.
If you’re unsure, calling a professional roofer who specializes in SPF is a smart move, as they can perform a moisture scan and closely examine the foam’s condition. When discussing options with a contractor, ask, “How much moisture testing will you perform to assess the existing foam’s condition?” and “What warranty differences should I expect between doing an overlay versus a full tear-off?” These questions help clarify the likely lifespan and risks of each option. Since improper overlays can trap moisture or worsen damage, ensuring the roofer follows manufacturer guidelines and industry standards protects your investment and keeps any existing or new warranties intact. Ultimately, safety and longevity come first; when in doubt, a tear-off, although pricier, often avoids bigger problems down the road.