What is the life expectancy of 30 lb felt?

Author: Johnnie Bauch  |  Last update: Sunday, February 23, 2025

But 30-lb felt or hot-mop asphalt has a limited lifespan. So you end up tearing off that perfectly sound tile roof every 20 or 30 years to replace the underlayment. A new product called QuickSilver , brings modern technology up to speed with some of these ancient, time tested materials.

How long does 30 lb roofing felt last?

Traditional Roof Felt (20-30 lbs): Standard felt underlayment typically lasts between 15 to 20 years when it is correctly installed and well-maintained. However, some may degrade sooner in harsh climates.

What is the life expectancy of roofing felt?

Typically, good quality roofing felt under tiles can last anywhere between 20 to 30 years. However, this lifespan isn't set in stone. It's subject to the variables discussed earlier, meaning it could be shorter or longer depending on those individual circumstances.

Which is better, 30-lb felt or synthetic underlayment?

It comes in two different weights: 15- and 30-pound, with 30-pound being the more durable, heavy option. Synthetic roofing underlayment is typically made from durable polymers that are created to be water-resistant and easy to work with. Many roofing contractors prefer to use synthetic roofing underlayment over felt.

How often should I replace my roof felt?

How often should roofing felt be replaced? The lifespan of roofing felt can change based on the type of material and the environment. On average, it lasts about 15 to 20 years. It's important to have regular inspections, especially for older roofs.

What Homeowners Should Know About Roofing Underlayment

Is it OK to put new roof felt over old?

Yes, you can put new roof felt over old roof felt. When this is done you should brush all the shingles and debris off of the surface. Then wash the roof down and fill in any indentations. With smaller roofs it is often better to strip back the roof and start again, an example of this would be shed felt.

Does roofing felt go bad?

The good news is that modern roofing felts withstand long-term exposure. They can be outside or on a store shelf for anywhere from six months to a year without any material impact on their ability to perform. Problems arise, however, when they're on a roof, and other factors affect how they look and their shape.

What is the longest lasting roof underlayment?

#1 Synthetic Underlayment

Synthetic underlayment is made of tough materials that effectively resist water and UV rays. Its textured surface provides improved traction for roofers, making it safer to work on sloped roofs, especially in wet or icy conditions. Estimated lifespan: 20 to 35 years.

Do roofers use felt anymore?

Felt roofing underlayment is a traditional material that has been used for decades and is still a popular choice for many roofing projects. Felt is made from either organic or synthetic materials, and is designed to provide a durable, waterproof barrier between the roof deck and the shingles.

Is 30 lb felt waterproof?

Today, according to the requirements laid out by ASTM D4869, #15 felt should weigh in at 34.6 pounds per 4-square roll, and #30 felt should weigh in at 43.2 pounds per 2-square roll. Felt underlayment is water-resistant thanks to the asphalt or bitumen used to make it, but is not waterproof.

Is it OK to leave old felt on shed roof?

It's not always necessary to tear off and remove the old roofing felt. But remember, if you are installing a whole new roofing system, removing the old one might be best.

What roofing material has the longest lifespan?

Slate, clay, concrete tiles, and metal roofing are among the longest-lasting options. They offer several decades of reliable service with intentional upkeep.

How to extend the life of a felt roof?

Tips To Extend the Lifespan of Your Flat Roof
  1. Inspect the Roof Regularly.
  2. Apply Elastomeric Roof Coating or Reflective Paint.
  3. Maintain Your Drainage System.
  4. Inspect the Interiors of the Property.
  5. Repair Swiftly.

How many square feet does 30-lb felt cover?

15 pound and 30 pound refers to the thickness of the felt, with the numbers indicating the weight of 100 square feet of this paper back when they were originally developed.

What is the lifespan of felt?

Asphalt felt, the most common type of underlayment has a lifespan of between 20 to 30 years. However, in extreme extended conditions, its lifespan can be cut by half. Fortunately, new rubberised or synthetic asphalt underlayment has a longer lifespan of between 25 and 35 years.

Can rain get through roof felt?

The felt absorbs and repels the water, but if the surface beneath the felt gets wet, it can lead to the dissolution of the subsurface as well as the roofing felt.

How do I know if my roof felt needs replacing?

The signs of a requirement for roof replacement include leaks, spots of natural light, visible damage to the felt, and cold spots or draughts. If you're unsure, you should always seek the advice of an expert roofing contractor who can complete a roof inspection.

What is better than roofing felt?

Many homeowners would prefer to invest in roofing materials that last for as long as possible, budget allowing. Rubber roofing like EPDM is considered a far superior product than traditional felt thanks to the wide range of benefits on offer.

Is 15lb felt better than 30lb felt?

If your roof does not have a steep pitch, you can use #15. This weight of felt is a good economic choice if you have a standard roof. But if your roof has a steep pitch, #30 is a better option because it is thicker and tears less during installation. With #30 you get a thicker layer of underlayment and protection.

Is peel and stick underlayment better than felt?

Unlike traditional asphalt felt, peel and stick roof underlayment doesn't wrinkle, which minimizes the risk of water pooling and penetrating the roof barrier below. Additionally, the absence of nail holes provides a more effective barrier against moisture.

How long can 30 felt paper be exposed?

Traditional felt underlayment, also known as tar paper, is generally rated to withstand exposure to the elements for a short period of around 30 to 90 days. On the other hand, modern synthetic underlayments are engineered for extended exposure, with some brands claiming to remain effective for six months to a year.

What is the life expectancy of roof underlayment?

Asphalt felt is the oldest and most common type of underlayment, and it typically lasts anywhere from 20 to 30 years, but in some cases it can last as little as eight. Newer synthetic or rubberized asphalt underlayments are much more durable than asphalt felt and offer better protection against water.

Can you put new roof felt over old?

Yes you can but it's not recommended. If you are replacing your shed roof felt it is typically because the old felt has broken down and is letting water in, not giving the protection it should. Removing the old felt will also allow you to see if there is any damage to the roof that needs fixing or replacing.

Should roofing felt be pulled tight?

Never pull your roof membrane under tiles too tight

The ideal measurement of this will sit between a minimum of 10mm and a maximum 15mm. If the membrane is taught, there is risk of tearing and the water could become trapped behind the tiling batten.

How often should a felt roof be replaced?

Felt roofing can last upwards of 15 years when maintained properly. With the right care, they can last for even longer. The material should be repaired as and when problems occur to uphold the integrity of the structure. As it gets older, it's more likely to be weaker and prone to weather damage.

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