The answer to 'how to maintain underlayment' is to regularly inspect and repair any damage to the underlayment on your roof. Underlayment is the protective layer installed beneath the shingles or other roofing material. It helps prevent water leaks and protects the roof deck from moisture.
To maintain your underlayment, visually inspect it at least once a year, typically in the spring or fall. Look for any rips, tears, or areas where the underlayment is missing or damaged. Repair any issues promptly using a compatible roofing sealant or by replacing the damaged sections. It's also important to keep the underlayment free of debris, such as leaves or twigs, which can cause damage over time. If you notice significant deterioration or are unsure how to properly maintain the underlayment, it's best to consult a professional roofing contractor.