Can Roofing Felt Get Wet: What Happens and How to Protect It

Roofing felt is a common underlayment used beneath shingles and other roofing materials, and many homeowners and contractors ask, Can roofing felt get wet? This article explains how different types of roofing felt react to moisture, the risks of exposure during storage and installation, and best practices to prevent damage and ensure a durable roof.

Felt Type	Typical Water Resistance	Common Issues If Wet
Asphalt-Saturated Tar Paper	Moderate; resists light moisture	Softening, tearing, delayed adhesion
Asphalt-Saturated Cotton/Organic Felt	Low; absorbs water	Mold, rot, loss of structural integrity
Synthetic Roofing Underlayment	High; designed shed water	Minimal if exposed briefly

What Roofing Felt Is And Why Moisture Matters

Roofing felt, often called tar paper or underlayment, is a protective layer installed between the roof deck and the shingles. Its primary role is to provide a temporary weather barrier and secondary waterproofing, helping prevent leaks if shingles are damaged or blown off.

Because roofing felt is a barrier rather than a waterproof membrane, exposure to water during storage or installation can compromise its function. Understanding whether roofing felt can get wet and what that means can avoid premature roof failures.

Types Of Roofing Felt And Their Water Resistance

Not all roofing felts are created equal; the material composition affects how they handle moisture. Organic felts absorb water and are more vulnerable, while modern synthetic underlayments offer better resistance.

• Organic/Asphalt-Saturated Felt: Made from cellulose or fiberglass mats saturated with asphalt, these felts can absorb water, swell, and degrade.
• Synthetic Underlayment: Constructed from polypropylene or polyester, synthetics are lightweight, shed water quickly, and resist tearing when wet.
• Asphalt-Saturated Tar Paper (15- or 30-pound): Traditional option with moderate resistance; resists brief exposure but can be damaged by prolonged wetting.

Can Roofing Felt Get Wet During Storage?

Roofing materials are sometimes stored on-site before installation, and exposure to rain or humidity can occur. Short periods of light moisture usually do not ruin modern synthetic underlayments, but organic felts are at greater risk.

When roofing felt gets wet in storage, problems can include staining, reduced tensile strength, mold growth on organic mats, and handling difficulties. Proper storage—covered, elevated, and ventilated—is essential to prevent these issues.

How Wet Roofing Felt Affects Installation And Performance

Installing wet roofing felt can complicate the roofing process and affect long-term performance. Wet felt can tear more easily, not adhere properly to the deck, and may allow trapped moisture to damage sheathing and trusses.

If roofing felt gets wet during installation, roofing crews should assess whether it can be dried in place, replaced, or requires additional steps like adding ventilation or a second layer of underlayment.

Short-Term Wet Exposure: What Contractors Recommend

If roofing felt gets wet briefly from a light rain, many contractors will proceed after inspection. Short-term wetting of synthetic or asphalt-saturated felts often causes no significant issues if panels are allowed to dry before shingle application.

Recommended steps include removing standing water, replacing sections that show visible damage, and ensuring the roof deck itself is dry and undamaged before continuing the job.

Long-Term Moisture Problems And Roof Deck Damage

Prolonged exposure to moisture can lead to serious problems beneath the felt. Organic felts that stay wet can promote mold, rot the roof deck, and decrease the lifespan of the roofing system.

Trapped moisture between felt and shingles or between felt and roof sheathing can cause buckling, shingle failure, and structural deterioration. Proper drying and venting strategies are critical after any extended wet exposure.

How To Dry Wet Roofing Felt And When To Replace It

Drying wet roofing felt depends on the extent of saturation and the felt type. Lightly wet synthetic felts often dry quickly and remain usable, while saturated organic felt typically requires replacement.

• For light wetting: Allow time to air dry if weather permits; check for soft spots or reduced strength before proceeding.
• For moderate wetting: Remove affected strips and replace; dry the deck and inspect for mold or rot.
• For heavy saturation: Replace all soaked underlayment; inspect and repair damaged sheathing before re-laying new felt.

Preventive Measures: Storage, Handling, And Jobsite Best Practices

Preventing roofing felt from getting wet is more efficient than repairing damage. Best practices include storing materials indoors or under protective coverings, elevating rolls off the ground, and installing underlayment promptly after roof deck exposure.

During installation, crews should unroll felt as needed, secure it in place to avoid wind lift, and avoid leaving exposed underlayment overnight in the event of predicted rain. Use fasteners and seam sealing recommended by the manufacturer.

Selecting The Right Underlayment For Wet Conditions

Choosing the correct product mitigates risk where moisture exposure is likely. In climates with frequent storms or for long projects, high-quality synthetic underlayments provide superior water resistance and durability.

Consider product features such as slip resistance, UV exposure tolerance, and manufacturer warranties. For reroofing projects where existing conditions may trap moisture, selecting a breathable or vapor-permeable underlayment can help manage trapped humidity.

Repairing Roofs After Felt Was Exposed To Water

If roofing felt gets wet and leaks occur, a systematic repair approach reduces further damage. Inspect the attic and ceiling for signs of leaks, remove and replace damaged felt and shingles, and repair any sheathing that shows softening or rot.

For visible mold or extensive water damage, consult a professional. Mold remediation and structural repairs may be necessary before installing new underlayment and shingles to avoid recurring issues.

Cost Impacts And When Replacement Is Necessary

Replacing wet roofing felt increases project cost and time. Costs depend on roof size, felt type, and extent of deck repair; synthetic underlayment is more expensive upfront but often reduces long-term risks and replacement frequency.

Replacement becomes necessary when felt loses integrity, shows persistent mold, or when sheathing is compromised. Early detection helps avoid more extensive and costly repairs.

Common Myths And Misconceptions About Roofing Felt And Water

Several misconceptions circulate among DIYers and homeowners. One myth is that roofing felt is fully waterproof; in reality, it is a secondary barrier and not meant to substitute for shingles or membranes.

Another belief is that all felts perform the same wetness; material differences matter a great deal, especially between organic felts and modern synthetics.

FAQ: Quick Answers About “Can Roofing Felt Get Wet”

• Can roofing felt get wet during a storm? Yes; short exposure to light rain may be tolerable, but prolonged exposure can damage the felt and roof deck.
• Is wet roofing felt dangerous to install? It can be riskier—wet felt is slippery and tears more easily, increasing safety and quality concerns.
• Can wet felt be dried in place? Lightly wet synthetic felt can often dry in place; saturated or organic felt usually should be removed and replaced.

Resources And Standards For Roofing Underlayment

Industry standards and manufacturer instructions provide guidance on moisture exposure. Refer to ASTM standards, local building codes, and product technical data sheets for installation and storage requirements.

Consulting experienced roofing contractors and seeking warranties from reputable manufacturers helps ensure the chosen underlayment performs as expected under wet conditions.

Practical Takeaways When Roofing Felt Gets Wet

When evaluating whether roofing felt can get wet, the most important factors are material type, duration of exposure, and subsequent handling. Use synthetic underlayment for better moisture resistance, protect materials in storage, and replace any felt that is saturated or compromised.

Prompt inspection and remediation minimize damage to roof decking and interior structures, preserving the long-term performance of the roofing system.