How much roof underlayment do I need?
Uses the same house size and pitch as the shingle calculator. Get rolls of synthetic underlayment or felt.
Synthetic (10 square rolls)
3 rolls
Estimated material cost
Synthetic
3 x $$90.00 per roll
$270
Typical store prices before tax and delivery. Change any price to match your store.
How to measure
Use the same measurements as the shingle calculator: house length, width, overhang, and roof pitch.
Tips from the field
- Use ice and water shield along eaves and in valleys, especially on low-slope roofs.
- Overlap rows the amount printed on the underlayment, usually 4 to 6 inches.
What you'll need
Common questions
Is synthetic underlayment better than felt?
Synthetic is lighter, stronger, and lasts longer if exposed before shingling. Felt is cheaper.
Where does ice and water shield go?
Along the eaves, in valleys, and around chimneys, skylights, and other roof penetrations.
How much does underlayment overlap?
Follow the marks printed on the roll, usually 4 to 6 inches on the sides and ends.
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Printed from housecalcs.com/tools/roof-underlayment-calculator