A strong and long-lasting roof does not depend on tiles, shingles, or the final waterproof layer alone. One of the most important but often ignored parts of a roof is roofing felt. Many homeowners do not realise that this hidden layer plays a major role in keeping the property dry, safe, and protected from weather damage. Roofing felt works as a secondary waterproof barrier, backing up your roof covering and adding extra strength to the entire roof system.
In this article, you will learn what roofing is, why it is important, where it is used, how it protects your home, and why professionals always recommend installing it, even if you already have a strong roof covering. This guide is written in simple and easy English so anyone can understand it, especially homeowners looking to improve their roof’s lifespan.
What Is Roofing Felt?
Roofing felt, also known as roof underlayment or felt paper, is a protective layer installed under tiles, shingles, or roofing sheets. It is usually made from fibreglass fleece, polyester, or cellulose materials soaked in bitumen or asphalt. This mixture makes the felt waterproof, durable, and resistant to tearing.
There are two main types of roofing felt:
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Bitumen Roofing Felt – Traditional, strong, and waterproof.
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Synthetic Roofing Felt – Lightweight, tear-resistant, easy to install, and modern.
Both are used widely, and the choice depends on roof design, weather conditions, and budget.
Why Roofing Felt Matters for Your Roof System
Roofing felt is not just an optional layer; it is a critical part of a complete roofing system. Here’s why it truly matters:
1. Acts as a Backup Waterproof Layer
Even the strongest roofing tiles or shingles can fail due to cracking, wind uplift, or ageing. Roofing works as a backup barrier that prevents rainwater from entering your property in case the top layer becomes damaged.
This means your home stays dry even when the roof covering fails.
2. Protects the Roof Deck
The wooden roof deck (OSB or plywood) can absorb moisture easily. When this happens, it leads to:
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Rotting
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Warping
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Mould growth
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Weak structural support
Roofing stops moisture from reaching the deck, helping it stay strong for many years.
3. Adds Fire Protection
Many roofing products come with fire-resistant properties, especially synthetic underlayments. This slows down the spread of fire, offering extra safety to your home.
4. Prevents Wind-Driven Rain
During storms, wind can push water under roof shingles or tiles. Without roofing , this water would go directly into your roof space. Felt blocks wind-driven rain and prevents internal leaks.
5. Helps Tiles and Shingles Sit Properly
Roofing felt provides a smooth, even surface, making it easier to install shingles or tiles. It improves adhesion and ensures the roof covering stays in place longer.
6. Protects During Roof Installation
When roofers are installing or repairing the roof, the felt keeps the deck dry even before the final roofing material is placed. This protects the structure during construction.
7. Reduces Noise
Roofing felt adds an extra layer that absorbs sound, making your home quieter during heavy rain or storms.
Major Benefits of Roofing Felt
1. Better Waterproofing
Roofing felt forms a tight seal that stops rainwater, moisture, and snow from entering your home.
2. Improved Roof Lifespan
With double protection, your roof lasts much longer and requires fewer repairs.
3. Affordable Upgrade
Compared to the total roofing cost, roofing is inexpensive but provides high-value protection.
4. Ideal for All Weather Conditions
It protects your home from extreme heat, heavy rain, ice, and strong winds.
5. Stops Moisture Build-Up
This prevents mould, mildew, and moisture damage inside the attic.
6. Helps Maintain Indoor Temperature
Roofing felt adds insulation support, helping your property stay warmer in winter and cooler in summer.
Installation Process of Roofing Felt
Roofing installation must be done carefully to avoid gaps, wrinkles, or loose sections. Here is the simple step-by-step method professionals use:
1. Preparing the Roof Deck
The roof surface is cleaned. Any old felt, debris, dust, or damaged boards are removed. A smooth, dry surface ensures proper adhesion.
2. Measuring and Cutting
The felt roll is measured according to roof dimensions and cut into workable sections.
3. Laying the First Layer
The first strip is placed along the eaves of the roof. It is rolled out smoothly to avoid wrinkles that may cause leaks later.
4. Overlapping the Layers
Each new strip overlaps the previous one by several inches. This directs rainwater downward without seeping between layers.
5. Securing the Felt
Roofers use galvanised nails or staples to secure the felt. In cold climates, adhesive may also be applied for extra bonding.
6. Sealing Joints and Edges
All edges, joints, valleys, and corners are sealed carefully to stop water penetration.
7. Installing the Final Roof Covering
After securing the felt, the roofer installs tiles, shingles, or roofing sheets on top.
Roofing Felt vs. Synthetic Underlayment
Many homeowners ask whether they should choose traditional roofing or synthetic underlayment. Here’s a simple comparison:
Roofing Felt
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Affordable
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Waterproof
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Easy to install
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Suitable for most roofs
Synthetic Underlayment
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Tear-resistant
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Lightweight
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UV-resistant
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Longer lifespan
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Better for extreme weather
Both perform well, but synthetic materials offer more durability. Your choice depends on your budget and roof type.
Common Problems When Roofing Felt Is Missing
If a roof does not have felt, several issues can occur:
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Frequent leaks
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Faster ageing of roof tiles
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Moisture damage inside attic
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Mould and condensation problems
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Weak roof structure
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Higher repair costs
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Reduced home value
This is why professionals highly recommend roofing as part of every roof system.
Tips to Maintain Your Roof System
Even with roofing felt, proper maintenance ensures your roof lasts longer:
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Inspect the roof twice a year
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Clear gutters and downpipes
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Replace loose or cracked tiles quickly
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Fix flashing issues early
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Check for sagging or soft spots
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Clean moss and algae regularly
Regular maintenance reduces the risk of leaks and water damage.
Is Roofing Felt Worth It?
Yes, roofing felt is absolutely worth it. It gives your home a strong, reliable, and protective base that keeps rain, moisture, and weather damage away. Without it, your roof system becomes weak and vulnerable.
Whether you are installing a new roof, repairing storm damage, or upgrading an old property, roofing should always be part of your roof design.
Conclusion
Roofing may look like a simple layer, but it plays a major role in creating a strong, reliable, and long-lasting roof system. It acts as a backup waterproof barrier, protects the roof deck, supports the final roof covering, and helps your home stay safe in all weather conditions. Whether you are building a new roof or upgrading an old one, installing high-quality roofing felt is one of the smartest decisions you can make. It improves durability, reduces repair costs, and keeps your property protected for many years. For the best results, always choose the right type of felt and have it installed by a professional roofer.