Does Roll Roofing Need Underlayment? Check the Answer

Roll roofing is just another option to make in terms of covering your roof with affordable material. It may not look as good as shingles, and by its low price, it is not that durable.

Many people still opt to use this roofing material especially for their utility structures, which often doesn’t require much aesthetics. However, despite its easiness to install, some people still wonder whether roll roofing needs underlayment?

Does Roll Roofing Need Underlayment And Benefits of Using It?

Some of you may not know what underlayment is. Underlayment is a barrier material, often installed directly upon the roof deck. This is done to protect the roof deck from condensation and any conditions resulted from severe weather.

Does Roll Roofing Need Underlayment

In recent days, these three types of underlayment are often used in roofing:

  1. Asphalt-saturated felt paper,
  2. A synthetic underlayment, and
  3. Rubber-asphalt underlayment

Asphalt-saturated felt underlayment is what most people were using before its synthetic replacement (asphalt-fiberglass combination) is massively produced. Both underlayment types are water-resistant, while the last type is waterproof.

Based on the layering properties alone, it can be inferred that using underlayment is useful as it can barrier your roof from moisture. Therefore, it saves your roof from getting ‘attacked’ by mold, especially if you use wooden material for your roof deck.

Now let’s get back to the topic: does roll roofing need underlayment? It is up to you to install it beforehand or skipping the underlayment and directly cover your roofing deck with roll roofing. Both methods are doable with their own advantage and risk.

If you decide to put on underlayment first, the roofing deck will be secured from water and moisture, but it surely will take more resources to purchase underlayment. The contradicting option requires less time and money to spend, but your roof will be prone to leaking and damage.

Although it saves money at first, after all, in the long term, it doesn’t serve as a good option. Therefore, it is advised to install underlayment before the roll roofing.

Installing underlayment isn’t difficult. You will only need some of the equipment to finish it:

  • Underlayment
  • Hammer
  • Chalk
  • Measuring tape
  • Utility knife to cut
  • Roofing nails

Then, the procedures to put on underlayment on your roof are as follows:

  1. First, make sure that you have attached the drip edge.
  2. Measure your underlayment’s length, then add it by 0.5-inch as an overhang on the drip edge.
  3. With your chalk, make a line with the measure you obtained in point (2). This is to help you align the underlayment while putting it on.
  4. Roll out the underlayment; make sure to do it well to have creases beneath the underlayment.
  5. If there’s uncovered space, continue putting on your underlayment with the same method; but make sure to create a 4-5-inch overlap between two underlayment sheets.
  6. You can secure the underlayment with roofing nails too.
  7. Continue it until all roofing deck surface has been covered with underlayment. Once you finished it, proceed with installing the roll roofing.

To sum it up, does roll roofing need underlayment? It is not compulsory, but much recommended to install it to avoid moisture and water from leaking through. It’s also important to ‘defend’ your roofing from within, from other extreme weather conditions, such as strong wind and scorching sun.

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RoofLast is an experienced author and roofing expert. With years of practical experience in the field authored several informative articles on various aspects of roofing, including installation, maintenance, and repair