How many square feet does one roll of underlayment cover?

Standard synthetic underlayment rolls cover roughly 1,000 sq ft (10 squares) after typical 4–6 inch overlaps at seams.

Do I need ice and water shield too?

In cold climates, ice-and-water shield is required at eaves, valleys, and around penetrations. Synthetic underlayment covers the rest of the field.

Calculator

A standard synthetic underlayment roll covers about 10 squares (1,000 sq ft) after overlaps. This calculator adds 10% for laps, ridges, and valleys.

Roof area

sq ft

Roll coverage

sq ft

Area with 10% laps

2,420 sq ft

Rolls

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How many square feet does one roll of underlayment cover?: Standard synthetic underlayment rolls cover roughly 1,000 sq ft (10 squares) after typical 4–6 inch overlaps at seams.
Do I need ice and water shield too?: In cold climates, ice-and-water shield is required at eaves, valleys, and around penetrations. Synthetic underlayment covers the rest of the field.

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