Are you yet to install shingles on your roof, leaving the underlayment exposed? Has the rain, hail, heat, and even aging shingles left your roof underlayment exposed?
If yes, you probably wonder whether your roof underlayment will stand the exposure. The good news is that roof underlayment can be exposed, but only for a while. So, how long can roof underlayment be exposed?
The length of time roofing underlayment can be exposed on the roof underlay material. You can let synthetic roofing underlayment be exposed for about three to six months. Synthetic roof underlays are resilient and can withstand different elements well. Asphalt-felt underlays should not be exposed to the weather for more than one to two weeks. However, both synthetic and felt underlay, when left under the sun for long periods, can dry out, become fragile and break apart.
Is Roof Underlayment Waterproof?
Roof underlayment is water-resistant but not entirely waterproof. Long periods of exposure to the rain can lead to damage. Notably, synthetic roof underlays will have more resilience under the rain than felt underlays.
Can Roof Underlayment Get Wet?
Roof underlayment can get wet since its water resistance is limited and temporary. If the roof underlayment gets wet, it can maintain its integrity for a few days (usually one to two weeks). After that, it becomes brittle and can break on exposure to sunlight.
Factors that Influence How Long you Expose Roofing Felt
Roof Type
The roof type determines how long the roofing felt can be left exposed. Some roof types collect more water than others do.
Leaving your roofing felt exposed in such types of roof can cause significant damage. Thus, you need to know your type of roof to determine how long you can leave felt exposed.
Weather Conditions
The weather conditions will influence how long roofing felt can be left exposed. Leaving roofing underlayment exposed in extreme weather conditions (whether too cold or too hot) can cause wrinkling and cracking of your roof underlayment.
You can avoid carrying out roof work when there are predictions for extreme weather conditions. But since the weather is unpredictable, you can ensure that roof underlayment is covered on the same day as installment.
Durability
The durability of the roofing felt can also determine how long it can be left exposed. Durable roofing felt such as synthetic underlayment can be left exposed for longer than asphalt felt underlayment. Synthetic underlayment is stronger than the asphalt felt, giving it a durability advantage.
Resistance to Moisture and Extreme Temperatures
You will also need to consider the resistance to moisture and extreme temperatures of the roofing felt. Since the weather can be unpredictable, you don’t want roofing felt that suffers damage after exposure to moisture and extreme temperatures. Synthetic underlayment is water-resistant and therefore can be exposed for longer times.
Self-Sealing Capability
Does your choice of roofing felt seal well around fasteners? If your roofing felt has a high self-sealing capability, it will be exposed for a shorter period. Synthetic underlayment is not self-sealing and thus may be exposed for a longer duration.
Installation
You should also consider the installation process in determining how long roofing felt can be left exposed. If the installation process takes longer due to issues such as material supply labor availability, among others, then your roofing felt will be left exposed for a longer time. In these cases, ensure you get synthetic underlayment as it can be left exposed for a longer time.
Why get Underlayment with Longer Exposure Ratings?
With the difference in exposure ratings for roof underlayment, which one should you get? I recommend that you get an underlayment with a longer exposure rating.
If you are wondering why you should get underlayment with longer exposure ratings, let’s dive into the reasons together.
Supply Delays
Have you ever waited for a delivery only to be told that there were supply delays? We all know the immense frustration that comes with this.
Underlayment with longer exposure ratings like a synthetic underlayment will save you from supply delays. It allows you to lay the underlayment and focus on other parts of the roof as you wait for your shipment to arrive.
Large Scale Projects
If you are undertaking a large-scale project, you may need to work in stages. In this case, you may not be able to cover the roofing with underlayment on the same day.
An underlayment with longer exposure ratings will allow you to do this comfortably. You will not have to worry about damage to the underlayment as long as you finish within the stipulated time.
Insurance Policy
What happens when a storm, hurricane, or tornado hits your area? The roofs will probably be blown off, and the demand for roof repair will spike.
Unfortunately, the available roofers may not satisfy the demand, and homeowners are left scrambling for the available roofers. However, you have a different insurance policy if you have roof underlayment with longer exposure ratings.
You know that your roof underlayment is intact and can safely protect your house until the next available roofer. Generally, synthetic underlayment has longer exposure ratings than other roof underlayments.
Asphalt Felt vs. Synthetic Underlayment.
Everyone wants that extra layer of protection for their roof provided by underlayment. But, how do you know which is the best underlayment?
There are two main types of roof underlayment; asphalt felt and synthetic underlayment.
As one of the oldest types of roofing underlayment, asphalt felt comes in 15lb and 30lb felt. The 30lb felt is thicker, stronger and there are lesser chances of it tearing.
Synthetic underlayment is relatively new in the market, having been in existence for a little over 20 years. While both will protect your roof, you need to consider both costs, safety, weight, and durability before making a purchase decision.
Cost is an important decision for all roof owners. After all, you don’t want a roof underlay that will go beyond your budget. Felt underlayment costs about five dollars for 100 square feet, which is considerably cheaper than synthetic underlayment costing 7-10 dollars per 100 square feet.
Closely associated with the cost is the durability of your roof underlayment. A durable underlayment will ensure you are not purchasing roof underlayment year in year out.
Synthetic underlayment is more durable than felt underlayment. It is strong, holds nails better during construction, and protects your roof adequately from bad weather.
On the other hand, asphalt felt underlayment is highly prone to tearing in the face of strong winds and construction strain. In addition, the exposure of asphalt felt underlayment to rain could cause it to wrinkle, affecting its durability.
Another factor you need to consider is the weight of the roof underlay. Asphalt felt is heavier than synthetic underlayment, which may slightly increase the labor costs.
Since asphalt felt is heavy, it will have less material per roll, which means you will need more of it. You will also need more labor to get it up to your roof during installation, which all sums up to an increased cost.
Your roofing contractor will need to walk on underlayment to install other materials on your roof. If the underlayment is not safe enough, it can be a trip or slip hazard, and you do not want roofing incidents.
Thus, safety should also be of utmost concern. Synthetic underlayment will be better than asphalt felt, as it is non-skid. The roofing contractors can walk on it with no fear of slipping or tripping.
So, asphalt felt vs. synthetic underlayment-which one should you get? I recommend that you select synthetic underlayment despite its high cost. The durability, safety, and longer exposure times will make it a worthy investment.
Will Exposure to Weather Destroy my Roof Underlayment?
Since I want you to understand everything concerning your roof investment, I will answer a common question among many homeowners. Will exposure to weather destroy my roof underlayment?
The quick answer- yes, exposure to weather will destroy your roof underlayment if you do not adhere to the manufacturer’s recommendations on exposure ratings.
The type of roof underlayment you use will also affect whether the weather will destroy your roof underlayment. Typically, felt roof underlayment exposed to weather will wear out more quickly than synthetic roof underlayment exposed to the weather for the same period. So how will rain, UV rays, and extreme temperatures destroy my roof underlayment?
Exposing felt roof underlayment to rain or wet weather may cause it to absorb water and eventually crack. Its exposure to high temperatures and UV rays will also degrade the material quickly, causing it to crack in the face of strong winds.
Instead, use asphalt felt if you’ll be covering the roof on the same day. If this is not possible, ensure that you don’t leave asphalt felt underlayment exposed for more than two weeks.
Synthetic roof underlayment is more resistant to weather. Synthetic felt will repel water instead of absorbing it with its water-resistant capabilities and plastic material.
Synthetic felt will not crack on exposure to extreme temperatures and UV rays like asphalt felt. However, you should not test its limits. Ensure that you follow the manufacturer’s recommendations and exposure ratings.
Most synthetic underlayment will resist weather damage for six to twelve months. If you exceed these times, you are most likely to grapple with the problems of brittle synthetic roof underlayment.
Is my Roof Underlayment Flammable?
You always want to know which parts of your house can catch fire quickly. After all, you would hate to be caught unaware amid an emergency like a fire.
So, you may be wondering, is your roof underlayment flammable? Both felt, and synthetic roof underlayment is flammable. They can cause fire to spread rapidly in your roof and the rest of the house.
Even the smallest source of fire on your roof underlayment like a match can wreak havoc into your home. However, felt underlays are more explosive than synthetic underlays. Synthetic underlays don’t burn as fast as felt and are less flammable, making your house safer if you have them on your roofing.
How Long Can Roof Underlayment Be Exposed FAQs
Can roof underlayment get rained on?
Your roof underlayment can get rained on. However, it would help if you did not allow this to continue beyond manufacturers’ stipulated and recommended time. For felt underlayment, you can only allow it to get rained on for a maximum of two weeks before it gets damaged. It can get rained on between six and twelve months without damage for synthetic underlayment, depending on the brand.
How long can a house go without shingles?
A house cannot go without shingles for very long. Typically, your house will go without shingles for about two months. However, after the first month, the sun’s heat damages the roof protection by drying out the oil on paper. Eventually, wind and rain can cause a tear, and water will begin to seep into your roof.
How long can 30 lb felt be exposed?
You can let the 30lb felt be exposed for about one to two weeks. Although the 30lb felt is thicker, stronger, and less likely to tear than the 15 lb felt, it is still prone to damage by elements. Exposure for longer periods may cause it to absorb water, tear and eventually wrinkle.
How long does roof underlayment last
Felt roof underlayment lasts for about 20 to 30 years with proper maintenance. However, in the absence of proper maintenance and extreme weather conditions, it may last for 10-15 years. Synthetic roof underlayment has a longer lifespan as it can last between 25 and 35 years.
Conclusion
You can leave your roof underlayment exposed for two weeks to twelve months, depending on the type. A felt underlay has a shorter exposure rating of one to two weeks, while you can expose a synthetic underlay for six to twelve months. To avoid the degradation and limitations that come with a felt underlay, get a synthetic roof underlayment to serve you for years to come.