Can You Put Roll Roofing Over Shingles

Roll roofing over shingles is a common question for homeowners seeking a quick, lower-cost roof update; this article explains when it is possible, what building codes say, installation steps, pros and cons, cost and maintenance considerations to make an informed decision.

Factor	Summary
Allowable By Code	Often Allowed Once Over, Local Codes Vary
Best Condition For Installation	Plywood/OSB Decking Sound, Existing Shingles Flat And Secure
Typical Benefits	Lower Cost, Faster Installation, Temporary Protection
Main Risks	Trapped Moisture, Reduced Lifespan, Warranty Void

How Building Codes And Local Rules Affect Adding Roll Roofing

Building codes and local ordinances determine whether roll roofing can be installed over existing shingles; in many U.S. jurisdictions one overlay is allowed, but local code inspectors and HOA rules may impose additional restrictions.

It Is Crucial To Verify Permit Requirements And Maximum Layers Allowed With The Local Building Department because some areas restrict overlays to prevent excessive roof weight and moisture entrapment.

When It Is Appropriate To Install Roll Roofing Over Shingles

Overlaying roll roofing is most appropriate for low-slope roofs and when the existing shingle layer is one single, well-adhered layer with no structural decay; it is less appropriate on steep roofs or roofs with multiple layers of shingles or significant deterioration.

Roll Roofing Typically Works Best On Shed, Porch, Or Garage Roofs Rather Than Complex Main Roofs because these applications have simpler flashing needs and lower exposure to foot traffic and weather-driven stress.

Benefits Of Putting Roll Roofing Over Shingles

Primary benefits include cost savings, faster installation, and immediate weatherproofing; roll roofing materials are inexpensive and can be applied quickly compared with full tear-off and re-roofing.

• Lower Material And Labor Costs: Less removal labor means lower overall expense.
• Faster Project Timeline: Overlay can be completed in hours to a day for small roofs.
• Temporary Protection: Useful for short-term fixes or budget-constrained scenarios.

Risks And Limitations To Consider

Overlaying roll roofing creates risks including trapped moisture, limited lifespan, and potential warranty voids; these factors can reduce long-term roof performance and lead to hidden damage.

Roll Roofing Over Shingles Can Conceal Structural Problems That Require Tear-Off To Repair, Such As Rot Or Poor Flashing, Which Could Increase Future Costs.

Preparing The Existing Roof For Roll Roofing Overlay

Proper preparation increases the chance of success: inspect, repair, and clean the surface before applying roll roofing; ensure shingles are flat, secure, and the roof deck is structurally sound.

1. Inspect For Rot And Structural Damage: Replace damaged sheathing and reinforce framing before overlay.
2. Secure Loose Shingles And Remove Debris: Fasten loose shingles and remove nails, gravel, and dirt.
3. Check And Repair Flashing: Replace compromised flashing around chimneys, vents, and valleys.

Step-By-Step Installation Overview

The installation process involves measuring and cutting, underlayment application if required, and adhering roll roofing with nails and sealant; detail-focused work at edges and penetrations helps prevent leaks.

1. Measure And Cut Rolls To Fit: Allow for adequate overlap along seams and at eaves.
2. Add An Approved Underlayment If Required: Some codes or best practices call for a slip sheet or felt layer between shingles and roll roofing.
3. Install Roll Roofing From Eave To Ridge: Start at the lower edge and roll up, nailing per manufacturer specs.
4. Seal Seams And Flashing: Use compatible roofing cement or adhesive at overlaps and around penetrations.

Material Choices And Product Considerations

Roll roofing materials include smooth-surfaced mineral, granular-surfaced, and modified bitumen varieties; selecting the right type depends on slope, exposure, and desired lifespan.

Granular-Surfaced Roll Roofing Provides Better UV Resistance, While Smooth Or Peel-And-Stick Options May Be Easier To Install On Smaller Projects.

How Overlay Affects Roof Lifespan And Warranties

An overlay generally shortens the effective remaining lifespan of the roofing system compared with a full tear-off and re-roofing; many manufacturers void full warranties if new materials are installed over existing shingles.

Expect Roll Roofing Over Shingles To Last Less Than A Standard Shingle Replacement—Often 5 To 15 Years Depending On Conditions—While A New Shingle Roof Could Last 20+ Years.

Cost Comparison And Budget Planning

Overlay costs are typically a fraction of full tear-off replacement costs; labor and disposal savings are primary drivers; however overlays can increase long-term costs if hidden damage remains untreated.

Project Type	Typical Cost Range Per Square
Roll Roofing Overlay	$50 – $150
Full Shingle Tear-Off & Replacement	$300 – $700

Costs Vary By Region, Roof Complexity, And Material Quality—Obtain Multiple Quotes And Check Contractor Credentials.

Alternatives To Putting Roll Roofing Over Shingles

Alternatives include a full tear-off and re-roofing, using metal roofing, or applying specialty membrane systems; each option has different longevity, cost, and performance trade-offs.

• Tear-Off And Re-Roof: Higher upfront cost, longer lifespan, and better warranty options.
• Standing Seam Metal Or Metal Panels: Durable and low-maintenance but higher material and labor costs.
• Rubber Or TPO Membranes: Effective for low-slope roofs with excellent waterproofing when installed correctly.

Maintenance, Inspection, And When To Replace

Regular inspections every six months and after major storms help detect failure points early; maintain sealants, clear debris, and repair seams as needed to extend service life.

Replace The System When Multiple Leaks Occur, When Significant Granule Loss Or Blistering Appears, Or When Underlying Decking Shows Signs Of Rot.

Common FAQs Homeowners Ask

Will Roll Roofing Be As Durable As New Asphalt Shingles?

No—roll roofing typically offers shorter durability and less aesthetic appeal compared with new asphalt shingles, especially on main living-area roofs.

Can Adding Roll Roofing Save Money Long-Term?

Short-Term Savings Are Real, But Hidden Damage Or Shorter Lifespan Can Make Overlays More Costly Over Time.

Is A Contractor Needed Or Can A Homeowner Do It Themselves?

DIY Is Possible For Small, Simple Roofs If The Homeowner Has Roofing Experience And Safety Gear; for complex or high-roof projects, a licensed contractor is recommended.

Inspection Checklist Before Committing To An Overlay

Check	Acceptable Condition
Shingle Layer Count	One Layer
Decking Condition	Solid, No Rot
Flashing Integrity	Secure And Repaired
Roof Slope	Low To Moderate For Roll Roofing

Follow This Checklist To Reduce Risk And Make A More Informed Decision About Overlaying Roll Roofing Over Shingles.

How To Decide: Practical Decision Factors

Consider budget, roof condition, long-term plans for the property, and local code constraints when choosing whether to install roll roofing over shingles; weigh short-term savings against potential long-term cost and performance trade-offs.

When Preservation Of Property Value Or Maximum Longevity Is Important, A Full Tear-Off And Professional Re-Roof Is Often The Better Investment.

For Temporary, Low-Cost Protection On Simple Structures, Roll Roofing Over Shingles Can Be A Reasonable Choice If Done Correctly And Code Allows.