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How Long Can Tar Paper Be Exposed

Even though the protecting layer roofing felt is made to get wet, it doesn’t mean it can face exposure for extended periods. However, roofing felt sustains integrity after getting wet so long as it isn’t exposed to other elements for more than a week or two.

Here, you can find harsh sun and excessive moisture will cause it to degrade, so people ask, how long can roofing felt stay exposed, which poses questions about using roofing felt effective.

Durable paper that has been tar-impregnated is known as tar paper. Buildings use roofing paper to protect themselves from the elements by providing waterproofing. This material includes roofing underlay felt, asphalt paper, tar paper, coal tar felt paper, roofing felt, and bitumen-impregnated felt paper.

Tar paper is not something most people see in everyday lives besides the most common area you see it in use, which is for roofing asphalt shingles where they need to withstand high winds and prevent leaks.

However, the robustness of felt roof underlay makes patching tears difficult without replacing much or all of it. In our guide, you can learn more about using these roofing materials to prevent water penetration. By the end, you’ll see the upsides and downsides and why synthetic underlayments can be a better option moving forward. (Learn How Long Does Tile Mortar Take To Dry)

Tar Paper underlayments

What You Need To Know About Underlay Roofing Felt

Most homes have tar paper. It’s typically used as a roof covering for modern homes but has additional purposes.

Because it’s so extensively used, many people don’t realize how long tar paper may be exposed to the elements before needing replacement or repair.

Different varieties of tar paper have differing life expectancies before needing replacement. The average lifespan of asphalt-based tar paper is three to eight years, depending on climate or area.

Fiberglass roofing, a popular tar paper synthetic underlayment and substitute, typically last 35 years. Metal or asphalt-soaked felt can survive 15 years or more before they break down.

Tar paper can be exposed to moisture for a while before deteriorating. For example, a new roof won’t reveal moisture damage for six months.

Reroofing includes peeling off all existing tar paper layers and exposing felt or substrate materials to moisture. Yet, you’ll need to replace damaged or decaying tar paper, even if the area is minor, to prevent further breakdown and possible water leaks.

How Do I Protect Roof from Rain?

The roofing protects a building from rain and snow. Weak roofs can collapse during earthquakes or storms.

A poorly built roof shortens the life of your home. However, properly waterproofed homes may hold off moisture for years while providing insulation to keep rooms warm in winter.

1. Roofing Material Used for Roof Protection

You should carefully select roofing material as it provides the basis of protection against the elements and more for your roof.

2. Proper Fitting of Roofing Material

Fixing the roof covering correctly is another crucial step in preserving roofs.

Properly installed sheet, drip edge, and crossings prevent water infiltration or seepage into your roof joints and trusses.

Galvanized nails are used to fix various sheet materials, which are chosen based on local climatic conditions.

3. Construction Methods

As with other construction works, following proper construction procedures is vital for protecting the roof.

When correctly attached, sheets won’t flap or lift in heavy winds, and leaks are avoided as a good example. (Read Can You Use Joint Compound On Cement Board)

4. Maintenance

Once your roof is protected, it needs some maintenance to detect and repair minor problems before they escalate.

Good practices for roof maintenance are:

  • Overloading roofs might create structural damage and eventual concerns.
  • Clean gutters avoid ice dams and allow rainfall to run freely, preventing water seepage through shingles.
  • During construction, adequately insulate between joists and rafters and trim all seams. After installation, trim edges flush.
  • When creating decks or porches, use pressure-treated wood.
  • Be careful when working on roofs. For example, avoid walking over nails that may pierce your foot, causing harm.

How Long Can Roofing Felt Be Exposed

The roof underlay is beneath the shingles on your roof. The underlayment is a material that overlaps and adds extra protection to your roof. However, when shingles are damaged, roof underlays may become visible.

If the roof underlayment comprises synthetic materials, it can be exposed for up to six months.

These non-felt roof underlays resist the elements well.

When you leave roofing felt exposed to the sun, the tiles or shingles dry out. When the sheets are completely dry, they become brittle and might split in severe wind or storm.

Can Roof Underlay Get Rained On

The answer is that roof underlay tiles can be exposed for a few weeks up to six months, depending on the material used.

Rain, however, frequently hastens the effects of the elements.

Rainwater can get on the roof underlay. However, using too much water could seriously destroy the underlay. Although underlays are water-resistant and can withstand some rain, they are not entirely waterproof.

Synthetic Roof Underlay

Which Is Better Felt or Synthetic Roof Underlay

Felt underlays or synthetic underlays are your two major options for roofing underlays.

Felt underlay is inferior to synthetic underlay as synthetic underlays are less likely to tear and more resistant.

In addition, synthetic underlays are lighter than natural roofing felt, and the weight your roof needs to support decreases.

Under ideal circumstances, felt underlays typically last ten to twenty years. However, synthetic underlayment can survive for 25 years or longer with little maintenance or replacement.

Except for installation costs, synthetic underlays are superior to the roofing felt in almost every regard.

The long-term cost of synthetic underlays, particularly in regions with harsh weather and high winds, can work out less expensive when including the cost of felt underlay repairs and replacement.

Are Roof Underlays Flammable

Even though roof underlays are flammable, they might still be exposed to the elements.

Roofing felt can quickly catch fire and spread it throughout your house.

Compared to synthetic underlays, roofing felt underlays are significantly more explosive. With felt underlays installed instead of synthetic underlays, your property is thus more susceptible to a severe fire.


How long can roof underlayment be exposed?

Most synthetic underlayment can be exposed for up to 6 months and others up to twelve. Despite minor pricing variations, asphalt felt roofing underlayment is still the least priced choice.

How long does tar paper last uncovered?

Traditional felt roofing underlayment typically has a lifespan of 12 to 20 years. However, the underlayment that lies beneath the surface of your roof could disintegrate or tear in a little over ten years if left exposed across the summer or the winter. (Learn How To Level A Ceiling With Furring Strips)

Can roofing paper get wet?

An essential insulating layer between the two layers of plywood and shingle that make up your roof is roofing felt or underlayment.

It offers superior leak protection and helps lessen the risk of wood rot on your house. Although roofing felt can become wet, it shouldn’t get too wet or stay wet for an extended period.

How long does it take tar paper to dry?

Since you never install shingles on wet roofing felt or roof underlayment, wait 24 hours for it to dry. If there is a further chance the roof will get wet, you’ll need to keep it covered and dry using a tarp.

Shingle on wet roof sheathing

Is it OK to shingle over wet felt?

Never lay shingle on wet roof sheathing or damp felt paper. Trapped moisture can’t evaporate once the sun heats the shingle, seeping into the edges and thus into the plywood underneath.

Can you shingle over wet plywood?

Never install a roof over wet plywood or any other sort of roof sheathing.

When the sun heats the roof, trapped water boils, and shingles develop little pits where the steam escapes.

Will synthetic underlayment keep rain out?

Yes, it will resist a rainstorm, and the underlayment can divert water away if needed. A synthetic underlayment can sit exposed in a rainstorm, although not too long.

What kind of roofing issues do you know?

Roofers cause most roofing problems. Exposed nails, incorrect flashing, especially on chimneys, shingle courses not adequately staggered, no clearance between shingle panels, and no clearance between roof decking panels.

You can also find asphalt shingle pressure-washing, no kick-out flashing, gutters, and downspouts discharging onto the roof, and no drip edge or rake edge flashing installed.

Besides this, the first shingle course with inadequate overhang or an old layer covered with a second layer of shingles.

Can you put a new roof felt over an old one?

Tar paper is another name for roofing underlayment. Under the shingles, it is placed on the roof deck.

The felt will be dried up, brittle, and coming apart when your
roof is worn out and you remove the old shingles.

Old shingles cannot be removed without damaging the felt layer. Therefore, the answer is that you cannot.

  1. After removing the old shingles and felt, carefully go over the roof deck and remove every last nail and staple left behind from the previous roof.
  2. The roof deck is then repaired, and any rotting decking is replaced.
  3. Then you apply new felt. Install the drip edge after that by moving around the edge.
  4. Lastly, proceed to the bottom edge, begin on one end, and install the new shingles in layers as directed.

How Long Can Tar Paper Be Exposed