The answer to 'how to clean underlayment' is to regularly inspect and clean the underlayment beneath your roof. Underlayment is the water-resistant barrier installed between the roof deck and the roofing material. Keeping it clean is important to maintain its protective function and prevent leaks or water damage.
To clean the underlayment, start by safely accessing the roof using a ladder or other equipment. Carefully inspect the underlayment for any debris, dirt, or other materials that have accumulated. Use a soft-bristle brush or broom to gently sweep away any loose debris. Avoid using harsh chemicals or pressure washers, as these can damage the underlayment. If you encounter any areas with significant buildup or staining, you can use a mild, pH-neutral cleaner and a soft cloth to spot clean those sections. Be sure to rinse the area thoroughly with clean water afterwards.