Can metal roof panels be installed over existing roofs?
Sep 23, 2025
Metal roof panels can usually be installed on top of existing roofs. This “roof installation” scheme is relatively common in industrial plants, warehouses, and renovation of old buildings.
The metal roof panel itself is light in weight, with a conventional weight of 10-30 kg/㎡, which is much lower than the weight of the concrete roof (200-300 kg/㎡), and if the existing roof (such as concrete roof, steel roof) is structurally sound, it can carry additional loads without substantial reinforcement. And different corresponding solutions can be selected for different original roofs: the concrete roof is fixed with galvanized C-shaped steel purlins + expansion bolts, the old metal roof is connected with aluminum alloy keels (lightweight) + waterproof gasket screws, and the wooden roof is anti-corrosion Purlins can avoid damaging the original structure and are flexible.
If the existing roof waterproofing layer is intact and only slightly defective, it can be installed directly after cleaning. There is no need to remove the old roof, eliminating the cost of demolition and garbage removal. The construction period is more than 50% shorter than “demolition and reconstruction”. It is suitable for buildings that need to be quickly restored to use (such as factories and warehouses), with low cost and short construction period. At the same time, the metal roof panel also protects the original roof。At the same time, it can isolate rain, snow, and ultraviolet rays, extend the service life of the old roof base (such as concrete and wooden keels), and reduce the frequency of repair of the original roof. And General metal roof panels have low thermal conductivity, good thermal insulation performance, good fire protection performance, high safety factor, fire protection, wind resistance, and corrosion resistance (such as aluminum-magnesium-manganese plates, galvanized color steel plates), which can improve the overall disaster resistance of the roof. ability.
Overall, if the original roof structure is intact and the load-bearing capacity is sufficient, the installation of metal roof panels is a cost-effective renovation plan.