Roof Underlayment Replacement Cost Calculator
This roof underlayment replacement cost calculator estimates what it could cost to replace the underlayment on your roof. Choose felt, synthetic or peel-and-stick underlayment, enter your home or roof size, and choose whether it is part of a full roof replacement or a lift-and-re-lay of existing tile, slate or metal.
Results show the underlayment cost per square foot and the full project range, so you can see what the underlayment itself costs and what has to happen around it.
This calculator provides a planning estimate only. It is not a quote, bid or guarantee of price. Actual contractor pricing may vary based on location, site conditions, material choice, labor market and project complexity. Permit and inspection amounts are allowances and do not represent the actual fees charged by your local building department.
Underlayment is the water-resistant layer between your roof deck and the roofing on top. It is cheap per square foot, but it cannot be replaced without removing the roofing above it, so most of the cost of an underlayment project is the work around it: tear-off, disposal, deck repair and putting roofing back.
This calculator prices those pieces separately, so you can see the cost of the underlayment itself and the cost of the project it belongs to.
How to Read Your Roofing Estimate
Underlayment cost per square foot
Materials plus labor for the underlayment alone, before tear-off and other project costs.
Typical project total
The middle scenario, including removal of the old roofing (or careful lifting of reusable roofing), deck repair allowance, permit and extras. New roofing is not included unless you choose the re-lay option.
Budget, Standard and Premium
Three realistic scenarios. Budget assumes an entry-level product, an efficient crew and minimal extras. Standard assumes a mid-grade product and typical accessories. Premium assumes a top-tier product, a specialist crew and larger allowances for repairs and upgrades.
Ranges, not exact prices
Actual bids vary with local labor rates, roof access and contractor availability.
What Is Included in Each Cost Category
Materials
Underlayment, fasteners and caps, plus a 5% to 12% waste allowance. If you re-lay existing roofing, this also includes replacement tile, slate or panels for breakage.
Labor
Installing the underlayment, adjusted for slope, height and complexity. For re-lay projects it also includes putting the existing roofing back.
Removal / tear-off
Stripping the old roofing so the old underlayment can come off. For re-lay projects this is careful lifting, sorting and stacking.
Disposal
Dumpster, hauling and landfill fees for old roofing and underlayment.
Equipment & safety
Lifting equipment for heavy tile or slate re-lays, and extra safety gear for steep roofs or homes with three or more stories.
Permit / inspection allowance
A planning allowance only. Your local building department sets the real fee.
Additional project costs
Roof deck repair, ice and water shield at eaves and valleys, and new drip edge and starter strip.
Categories that do not apply to your project, such as tear-off for new construction, are hidden rather than shown as $0.
Get matched with local roofing professionals
After you calculate, use this form to request quotes from local roofing professionals. Your estimate and project details will be passed to the form automatically once it is connected.
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How Much Does Roof Underlayment Replacement Cost?
Roof underlayment itself costs about $0.30 to $2.55 per square foot installed, depending on the type, from basic felt to high-temperature peel-and-stick. But the underlayment sits under your roofing, so a replacement project usually costs roughly $2 to $4 per square foot once the old roofing is removed, and far more if existing tile, slate or metal is lifted and re-laid. These numbers are planning assumptions used by this calculator, not live contractor bids. Use them to see how much of your budget is the underlayment and how much is the work around it.
$0.30 – $2.55
Per square foot, installed
Underlayment alone, from basic felt to high-temperature peel-and-stick.
$2 – $4
Per square foot, project
Typical replacement project once the old roofing is removed.
$5,350 – $6,150
Worked example, standard
2,000 sq ft home, synthetic underlayment, not including new roofing.
How This Underlayment Replacement Calculator Works
Roof area
Enter your home footprint (converted using your roof pitch) or your roof surface area directly.
Underlayment type
15-lb felt, 30-lb felt, synthetic, peel-and-stick or high-temperature peel-and-stick, each with its own material and labor rates.
Project scope
Part of a full roof replacement, or a lift and re-lay of your existing tile, slate or metal.
Adjustments
Labor is scaled for pitch, stories and complexity, and materials include a waste allowance.
Project extras
Tear-off or careful lifting, disposal, deck repair, ice and water shield, drip edge and permit allowance are priced separately.
ZIP code
Your ZIP code identifies your market and helps match you with local professionals. It does not change the calculated price.
What Is Roof Underlayment?
Underlayment is a layer installed directly over the roof deck and under the roofing material. It acts as a backup barrier against wind-driven rain and protects the deck while the roof is being installed. Building codes generally require underlayment under most roofing, and low-slope roofs often need extra layers or a self-adhered product, so check what your local code requires.
Underlayment Cost by Type
The table shows the installed cost the calculator starts from (materials plus labor) for a simple, single-story roof, before waste, height adjustments, tear-off and extras.
| Underlayment type | Budget – Premium per sq ft | Typical per sq ft | Notes |
|---|---|---|---|
| 15-lb asphalt felt | $0.30 – $0.54 | $0.40 | Basic, lowest cost |
| 30-lb asphalt felt | $0.40 – $0.70 | $0.53 | Heavier, more durable felt |
| Synthetic | $0.50 – $0.96 | $0.70 | Tear-resistant, popular upgrade |
| Self-adhered (peel-and-stick) | $1.25 – $2.35 | $1.72 | Seals around nails, leak protection |
| High-temperature self-adhered | $1.35 – $2.55 | $1.87 | For metal and tile roofs |
Multiply per-square-foot figures by 100 to get the price per roofing square.
Felt vs. Synthetic vs. Peel-and-Stick
Asphalt felt
The traditional choice and the cheapest.
Synthetic
Made from polymers, generally stronger and more tear-resistant, and often chosen as an upgrade.
Self-adhered (peel-and-stick)
Bonds to the deck and seals around fasteners, which makes it popular at eaves, valleys and on low slopes, and under metal and tile where high temperatures are a concern. It costs the most per square foot, but it can add meaningful leak protection.
In the calculator’s example, switching from synthetic to peel-and-stick adds roughly $2,700 to $3,050 to the project on a 2,440 square foot roof.
Why Underlayment Cannot Be Replaced on Its Own
Underlayment is installed beneath the roofing, so replacing it means removing the roofing first. For asphalt shingles that usually means a full re-roof, since shingles are rarely reused. Because of that, this calculator treats underlayment replacement as part of a roof replacement or as a lift-and-re-lay project. In the roof replacement case, the new roofing material is priced separately in the matching roofing calculator.
Lift and Re-Lay: Tile, Slate and Metal
Tile, slate and metal roofs often outlast their underlayment. When the roofing is in good shape but the underlayment has worn out, a contractor can carefully lift and stack the roofing, install new underlayment and re-lay the roofing with replacements for broken pieces. This avoids buying all-new roofing but takes skilled labor.
$23,500 – $27,000
Re-laying tile, synthetic
2,000 sq ft home, calculator example.
$17,700 – $20,400
Re-laying metal panels
2,000 sq ft home, calculator example.
$36,200 – $41,600
Re-laying slate
2,000 sq ft home, calculator example.
Older tile and slate can break during lifting, and matching replacements may be hard to find.
What Affects the Cost of Underlayment Replacement?
Underlayment type
Type drives the underlayment cost itself. Felt is cheapest and peel-and-stick is the most expensive, with synthetic in between.
Roof size and pitch
Cost scales with roof surface area, which is larger than your home footprint. The calculator multiplies footprint by about 1.12 for low pitch, 1.22 for medium, 1.38 for steep and 1.55 for very steep roofs. Steeper roofs add labor, safety and staging costs.
Roof complexity
Valleys, hips, dormers and penetrations create more cutting and waste. The calculator uses a 5% waste allowance for simple roofs, 8% for moderate and 12% for complex ones.
Tear-off and disposal
Removing the old roofing is the largest cost in a typical underlayment project. In the example, removing one layer of asphalt shingles is included in the standard result. Two layers add roughly $2,200 to $2,500, and removing old tile or slate adds roughly $4,600 to $5,250.
Roof deck repair
Old underlayment often hides damaged sheathing. In the example, extensive deck repair adds roughly $2,300 to $2,650 compared with minor repair.
Ice and water shield and drip edge
Ice and water shield at eaves and valleys, and new drip edge and starter strip, add protection at the most leak-prone parts of the roof. Together they add roughly $800 to $900 in the example.
Building height and equipment
Three-story homes and steep roofs add safety gear and staging, and heavy tile or slate re-lays add lifting equipment.
Permits and regional pricing
Permit fees, labor rates and code requirements vary by region. Some areas require specific underlayment types on low slopes or in cold or high-wind zones.
How Long Does Roof Underlayment Last?
Underlayment lifespan depends on the product, climate and what covers it. Felt is commonly expected to last on the order of 10 to 20 years once covered, while synthetic and self-adhered products are often expected to last longer, but exposure during installation and heat under metal or tile can shorten life. The goal is to match the underlayment to the roofing above it so you are not tearing the roof apart again for the underlayment.
Worked Example: 2,000 Sq Ft Home
2,000 sq ft home · 2 stories · Medium pitch · Moderate complexity · Synthetic
Take a two-story home with a 2,000 square foot footprint, medium pitch, moderate complexity, synthetic underlayment, one layer of asphalt shingles to remove, minor deck repair and a permit allowance. The footprint converts to about 2,440 square feet of roof (24.4 squares).
2,440 sq ft
Roof area
24.4 squares
$0.76 – $0.87
Per sq ft, underlayment
Standard scenario, synthetic
$5,350 – $6,150
Standard project total
$2.20 to $2.50 per square foot all-in, not including new roofing
$3,600 – $4,100
Budget scenario
Same home, budget assumptions
$7,850 – $9,050
Premium scenario
Same home, premium assumptions
$4,600 – $5,250
With 15-lb felt
Project total, same home
$8,050 – $9,200
With peel-and-stick
Project total, same home
How to Budget for Underlayment Replacement
Plan it with your roofing project
Replacing underlayment is cheapest when done with a roof replacement.
Match the underlayment to the roofing
Use high-temperature products under metal and tile.
Add contingency
Add 10% to 15% contingency for hidden deck damage.
Compare quotes
Get at least three written quotes and compare the underlayment brand, layers and where it is installed.
Check warranties
Some roofing warranties require specific underlayment.
Questions to Ask Roofing Contractors
- Which underlayment brand and type are you quoting?
- Where will you install peel-and-stick, and where will you use other underlayment?
- Is the underlayment rated for the temperatures under my roofing?
- How do you price deck repair?
- If my roofing is being re-laid, how will you handle breakage and matching pieces?
- Does my roofing warranty require a specific underlayment?
- Who pulls the permit?
When to Hire a Professional
Underlayment installation affects how well your roof sheds water for decades. Use this estimate to plan, then get quotes from licensed local roofers to confirm scope and price.
Quick Answers
How much does roof underlayment cost per square foot?
Roof underlayment typically costs about $0.30 to $2.55 per square foot installed, depending on the type. Felt is the cheapest, synthetic is in the middle, and peel-and-stick is the most expensive.
How much does it cost to replace roof underlayment?
Because underlayment sits under the roofing, replacement usually costs roughly $2 to $4 per square foot once the old roofing is removed. For a 2,000 square foot home in this calculator’s example, the project is roughly $5,350 to $6,150 with synthetic underlayment, not including new roofing.
Can you replace roof underlayment without replacing the roof?
Only if the roofing can be removed and reused, such as tile, slate or metal. Asphalt shingles are usually replaced along with the underlayment.
What is the best roof underlayment?
It depends on the roof. Synthetic is a popular all-round upgrade, peel-and-stick is often used at eaves, valleys and low slopes, and high-temperature peel-and-stick is common under metal and tile.
How long does roof underlayment last?
Felt is commonly expected to last on the order of 10 to 20 years once covered, while synthetic and self-adhered products are often expected to last longer, depending on exposure and heat.
Frequently Asked Questions
How much does roof underlayment cost per square foot?
Roof underlayment typically costs about $0.30 to $2.55 per square foot installed, depending on the type. 15-lb felt is the cheapest, synthetic is in the middle, and peel-and-stick is the most expensive. These are planning figures, and the full project also includes removing the old roofing.
How much does it cost to replace roof underlayment on a 2,000 square foot house?
A home with a 2,000 square foot footprint and medium pitch has about 2,440 square feet of roof. In this calculator’s example, replacing the underlayment with synthetic underlayment as part of a roof replacement is roughly $5,350 to $6,150, including tear-off of one asphalt layer, disposal, minor deck repair and a permit allowance. New roofing is not included.
Can underlayment be replaced without removing the roof?
No. Underlayment sits between the deck and the roofing, so the roofing must come off first. Tile, slate and metal can sometimes be lifted, stacked and re-laid over new underlayment, but asphalt shingles are usually replaced.
Is synthetic underlayment worth it over felt?
Many roofers recommend synthetic because it is generally more tear-resistant and holds up better during installation. It costs more than felt, in this calculator about $0.30 per square foot more at standard pricing, or roughly $750 more on a 2,440 square foot roof. Check what your roofing manufacturer requires.
When should I use peel-and-stick underlayment?
Peel-and-stick is commonly used at eaves, valleys and low slopes, and in cold or storm-prone areas, because it bonds to the deck and seals around fasteners. High-temperature versions are often specified under metal and tile. It costs the most per square foot, so many projects use it only where it matters most.
How long does roof underlayment last?
Felt is commonly expected to last on the order of 10 to 20 years once covered, while synthetic and self-adhered products are often expected to last longer. Heat under metal or tile, exposure during installation and moisture can shorten life.
Is this underlayment estimate a quote?
No. It is a planning estimate based on typical project assumptions. Actual contractor pricing may vary based on location, site conditions, material choice, labor market and project complexity, so always get written quotes from licensed local roofers.
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Ready to Plan Your Roofing Project?
Underlayment installation affects how well your roof sheds water for decades. Use this estimate to plan, then get quotes from licensed local roofers to confirm scope and price.
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This calculator provides a planning estimate only. It is not a quote, bid or guarantee of price.