Torch-down roofing is a type of modified bitumen roofing system where a layer of bitumen is applied and melted onto the roof deck using a propane torch. Underlayment requirements for torch-down roofing are essential because the underlayment acts as a moisture barrier and provides extra protection for the roof deck against water infiltration. Typically, a high-quality, self-adhering ice and water shield or a compatible synthetic underlayment is needed beneath the torch-down membrane to prevent moisture from seeping through and causing damage to the roof structure. The underlayment must be placed carefully and meet manufacturer specifications to maintain warranty coverage and ensure the roofing system’s durability.
To check if your torch-down roof has the correct underlayment, look for signs of water stains inside your home or on the roof deck, which can indicate inadequate moisture protection. A gentle inspection around flashing, seams, and edges can reveal any peeling or bubbling that may suggest underlayment issues. While you can safely check visible areas, avoid tampering with the roofing membrane itself, as improper handling might void your warranty or damage the roof. If you see any signs of moisture damage or suspect the underlayment isn’t up to code, it’s best to call a licensed roofing professional. When consulting a contractor, ask if their underlayment meets local building codes and manufacturer recommendations for torch-down applications, and confirm whether they provide a warranty that covers both installation and materials.