Roofing felt is a common construction material laid under shingles or tiles for the roofing system. It is an additional layer of insulation for your home from moisture. The most common question is whether the roof felt is truly waterproof or not. Now the answer is simple, while being layered floor felt is water-resistant, but not waterproof under all conditions.
What Is Roofing Felt?
Roofing felt is an underlying coat or sheet of material, which may be natural or synthetic in composition, but with one or both sides soaked in asphalt or bitumen. There are various thicknesses, 15-pound or 30-pound varieties. It is usually laid over the roof deck before the final top rooftop material is placed.
How Waterproof Is Roofing Felt?
Roofing felt has never been intended to be used as the starting point for the waterproof barrier. It is temporary protection from moisture, mainly during the roof installation or in cases of broken shingles. However, prolonged exposures should not be permitted. If roofing felt gets exposed or damaged because of the weather roofing felt, can absorb water and become ineffective.
Roofing Felt Grades and Water Resistance
The most common types of roofing felts are two:
15-pound felt: Thin and light, for use with low-stress applications. It offers basic water resistance.
30-pound felt: Thicker and more durable. It has superior protection and can withstand longer against moisture longer.
The denser felts are found to resist penetration of water more effectively. Modern versions are fiberglass or polyester reinforced, and resistance to tearing and moisture is enhanced.
Comparison with Synthetic Underlayment
Synthetic underlayment is a new type of alternative to the felt. A solid, waterproof material made with polypropylene or other plastics. It also provides enhanced durability, longer UV resistance, and more slip resistance for installers. Yet, it is usually more costly than roofing felt.
When Roofing Felt Fails to be Waterproof
In these cases, roofing felt can fail as follows:
- When left out in direct sunlight or rain for a longer period before the roof’s final covering is done.
- When either torn or damaged during installation
- If improperly overlapped or nailed
- When used in extreme weather without protection
It is therefore why roofing felt is only used with a main roofing covering such as shingles, tiles or metal sheets.
Is Roofing Felt Protective in Construction in the Rain?
Yes, roofing felt can preserve the roof from light rain, when constructing. It helps to keep the decking for short periods dry. Contractors should, however, cover the felt as quickly as possible with permanent roofing to cut off water damage.
Can You Trust It if You Use Roofing Felt Alone?
No, never should roofing felt serve as the sole waterproofing material. It becomes a safety reservation if the outer roofing becomes defective or leaks. The main functionality of bitumen membrane is a temporary moisture protection and the enhancement of the performance of roof for the general purposes.
Conclusion
Roofing felt is water resisting not water proof. It guards against moisture on a temporary basis, and an element of a total roofing system. It however needs to be efficiently installed and overlaid with the major roof type soon. For longer and more lasting waterproofing, modern synthetic underlayment are better options.