Is it necessary to place a felt or coating under asphalt shingles?

Your roof is one of the most important features when it comes to your home. Having a properly installed roofing system will protect you from damage caused by hail and other harsh weather conditions. But underneath the asphalt shingles you are installed or planning to renovate, there is something that is even more important to keeping your home safe and secure: it is the roof covering. This will protect your attic even when there's a roof leak on the exterior. This is only necessary on wooden ceilings. On concrete ceilings it is not required.

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Roof sheathing is a membrane that is applied to your roof's wood, durock, or "deck" as an extra layer of protection against water penetration before asphalt shingles are installed. There are two roofing products that are known as ASPHALTIC FELT or SYNTHETIC COATING . Both fulfill the same waterproofing function, although they are not the same product. 

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Asphalt felt

Asphalt felt is made from asphalt-saturated felt to make it waterproof, the felt underlay for the roof also contains fiberglass reinforcement, which increases its strength and durability. However, over time, even the highest quality asphalt will wear down and be penetrable by water.

Felt roofing backing is usually a good choice for steep slopes, allowing water to drain off quickly. However, standing water is able to seep into it and infiltrate the roof structure. The felt base is also vulnerable to damage from the sun, which accelerates the deterioration of the asphalt, so it is not the best option for roofs that receive a lot of direct sunlight.

The felt also lacks the overall quality, durability, and total water resistance. If you require something inexpensive, asphalt felt would be functional and an excellent option, but in the event that you require greater protection, durability and quality, it would be more advisable to put a Synthetic Coating.

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Synthetic coating

The synthetic coating is an advanced membrane structure. Being totally waterproof, a highly protective insulation layer is added between the roof frame and the asphalt shingles.

It effectively protects against wind, rain and ice, helping to prevent water leaks regardless of the roof pitch. This type of synthetic coating is durable, long-lasting, lightweight, fungus resistant, and also highly reflective of direct UV radiation. In general, this type of roof covering receives better safety ratings than the alternatives. 

temporary protection‍

Felts or coatings can act as temporary roof protection before the asphalt shingle is installed. Generally, the asphalt shingle is installed immediately, however, in some circumstances where it is required to wait, if the Synthetic Coating is applied it can protect the roof and the wood from climatic elements such as ultraviolet radiation and rain for days, weeks or, even months. 

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What is the composition of the asphalt felt and synthetic coating? ‍

Asphalt saturated felt is a mixture of cellulose, polyester, bitumen and asphalt, soaked in a waterproofing agent. It comes in two thicknesses. Thirty pound felt is thicker and stiffer than fifteen pounds, so thirty pounds is more resistant to damage during installation and can protect the roof longer if exposed to outside elements such as rain, wind, hail, and snow .

Most synthetic coatings, on the other hand, are spun or woven from polypropylene or polyethylene. It is slim, adapts to surfaces and easy to handle. It is totally waterproof and very long-lasting and resistant.

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What is the best coating for your roof before the asphalt shingle? ‍

Synthetic coating is much lighter than asphalt felt therefore using synthetic materials will add less weight to the roof than any asphalt felt. Hope you enjoy my roof article of the month or day. I'll post again soon!