How To Refelt A Flat Shed Roof: A Step-by-Step Guide

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Is your shed roof looking a little worse for wear? Leaks, peeling felt, and general disrepair are all signs that it’s time to take action. The good news is, you don’t necessarily need to replace the entire roof structure. Often, the solution is much simpler: refelting.

Refelting a flat shed roof is a manageable DIY project that can significantly extend the life of your shed and protect your belongings from the elements. This guide will walk you through the entire process, from assessing the damage and gathering your materials to the final touches. We’ll cover everything you need to know to get the job done right, saving you money and giving you a sense of accomplishment.

So, are you ready to learn how to refelt a flat shed roof? Let’s get started!

Understanding the Need for Refelting

Before you dive into the project, it’s important to understand why refelting is necessary and what signs indicate it’s time for action. This section will cover the common causes of felt damage and how to identify them.

Why Does Shed Roofing Felt Fail?

Shed roof felt, typically made from bitumen-saturated felt, is exposed to the harsh elements. Over time, it degrades due to:

UV Radiation: Sunlight breaks down the bitumen, making the felt brittle.
Weathering: Rain, snow, and wind contribute to wear and tear.
Age: Even with good maintenance, felt has a limited lifespan, usually 10-15 years.
Poor Installation: Incorrectly installed felt can fail prematurely.
Punctures & Tears: Falling branches or objects can easily damage the felt.

Signs Your Shed Roof Needs Refelting

Recognizing the warning signs is crucial. Here’s what to look for:

Leaks: Water stains on the shed ceiling or inside the shed are the most obvious sign.
Blistering and Cracking: Bubbles or cracks in the felt indicate water penetration.
Peeling or Curling Edges: This is a sign of the felt detaching from the roof.
Missing Granules: The protective granules on the felt surface may wear away, exposing the bitumen.
General Deterioration: The felt may appear faded, brittle, or torn.

What If I Think the Structure Is Damaged and Not Just the Felt?

If you suspect structural damage to your shed roof, such as rotting timbers or sagging, refelting won’t solve the problem. In this case, you’ll need to address the structural issues before applying new felt. This might involve replacing damaged timbers or even rebuilding the roof. Check for:

Sagging: The roof should be flat and level.
Rotten Wood: Probe the wooden structure with a screwdriver to check for soft spots.
Loose Boards: Ensure all the roof boards are securely attached.

If the structure is sound, then refelting is likely the right solution.

Gathering Your Materials and Tools

Having the right tools and materials is essential for a smooth refelting process. This section will provide a comprehensive list of what you’ll need.

Essential Materials

New Roofing Felt: Choose a high-quality felt designed for flat roofs. Consider the size of your shed roof area to calculate the amount of felt. Measure the length and width of the roof, add a bit extra for overlap.
Felt Adhesive (Cold Applied): This is used to bond the felt to the roof surface. Select a product suitable for your type of roofing felt and the ambient temperature.
Felt Nails or Staples: These are used to secure the felt to the roof. Roofing nails are preferred for their durability.
Underlayment (Optional but Recommended): Provides an extra layer of protection and can help to smooth out any imperfections on the roof surface.
Primer (Optional but Recommended): Some surfaces benefit from a primer to improve the adhesion of the felt adhesive.
Bitumen Sealant/Lap Sealant: For sealing around edges, joints, and penetrations (such as vents or chimneys).

Necessary Tools

Measuring Tape: For accurate measurements.
Utility Knife or Roofing Knife: For cutting the felt.
Hammer or Staple Gun: For securing the felt. A staple gun will speed up the process.
Gloves: To protect your hands from the adhesive and sharp edges.
Safety Glasses: To protect your eyes.
Work Boots: To provide a secure footing on the roof.
Scraper or Wire Brush: For cleaning the roof surface.
Broom or Brush: For removing debris.
Ladder: Ensure your ladder is tall enough and stable.
Wheelbarrow or Container: For carrying materials up to the roof.

Safety Gear – Don’t Skip This!

Safety is paramount when working at heights. Always wear: (See Also: how to put a foundation under an existing shed)

Safety Glasses: Protect your eyes from debris.
Work Gloves: Protect your hands from adhesive and sharp edges.
Work Boots: Provide a secure grip on the roof surface.
Fall Protection (Highly Recommended): Consider using a safety harness and lifeline, especially if your roof is high or steep.
Ladder Safety: Ensure your ladder is stable and placed on a level surface. Have someone spot you if necessary.

Where to Buy Your Materials

You can purchase these materials at most home improvement stores, such as Home Depot, Lowe’s, or local hardware stores. You can also find them online through retailers like Amazon. Consider comparing prices and reading reviews before making your purchase.

Step-by-Step Guide to Refelting Your Shed Roof

Now, let’s get into the step-by-step process of refelting your shed roof. Follow these instructions carefully to ensure a successful outcome.

Prepare the Roof Surface: This is the most critical step. Remove all old felt, debris, and any loose nails or staples. Use a scraper or wire brush to remove any remaining adhesive or loose granules. Sweep the roof clean with a broom or brush. If the roof is particularly dirty, consider washing it with a mild detergent and water, then allowing it to dry completely.
Inspect the Roof Decking: Check the wooden decking beneath the felt for any rot or damage. Replace any damaged boards. Ensure the decking is level and secure.
Apply Primer (Optional): If you’re using a primer, apply it to the roof surface according to the manufacturer’s instructions. This will improve the adhesion of the felt adhesive. Allow the primer to dry completely before proceeding.
Install Underlayment (Optional but Recommended): If you’re using underlayment, roll it out across the roof surface, overlapping the edges by at least 4 inches. Secure the underlayment with staples or roofing nails, spacing them according to the manufacturer’s instructions.
Cut the Felt: Measure and cut the felt sheets to the required size, allowing for an overlap of at least 4 inches at the edges and joints. Use a utility knife or roofing knife for clean cuts.
Apply Felt Adhesive: Apply a generous amount of felt adhesive to the roof surface where you’ll be laying the felt. Follow the manufacturer’s instructions for the adhesive.
Position the First Sheet of Felt: Carefully position the first sheet of felt, ensuring it’s aligned correctly. Start at the bottom edge of the roof (the eaves) and work your way up.
Secure the Felt: Once the felt is in position, secure it with felt nails or staples. Space the nails or staples according to the manufacturer’s instructions, typically about 4-6 inches apart along the edges and 6-8 inches apart across the field of the felt.
Overlap the Sheets: Overlap the edges of the felt sheets by at least 4 inches. Apply felt adhesive to the overlapping edges to create a watertight seal.
Seal the Seams: Apply bitumen sealant or lap sealant to all seams, edges, and around any penetrations (such as vents or chimneys) to prevent water from entering.
Repeat for Remaining Sheets: Continue applying felt sheets, overlapping them and securing them with nails or staples, until the entire roof is covered.
Trim the Edges: Once all the felt sheets are in place, trim any excess felt along the edges of the roof.
Final Inspection: Carefully inspect the entire roof for any gaps, loose nails or staples, or areas where the felt isn’t properly sealed. Make any necessary repairs.
Clean Up: Remove any debris from the roof and dispose of it properly. Clean your tools and store them safely.

Tips for Working with Felt

Work in manageable sections: Don’t try to apply too much adhesive or felt at once.
Avoid working in extreme temperatures: High heat can make the adhesive runny, while cold temperatures can make the felt brittle.
Use a roller or weighted object: To ensure the felt adheres properly to the roof surface.
Work with a partner: Especially when handling large sheets of felt.
Read the manufacturer’s instructions: For all materials, including felt, adhesive, and sealant.

How to Refelt Around Chimneys and Vents

If your shed roof has chimneys, vents, or other penetrations, you’ll need to pay special attention to sealing around these areas to prevent leaks. Here’s how:

Cut the Felt: Carefully cut the felt around the penetration, leaving a small gap for sealant.
Apply Sealant: Apply a generous amount of bitumen sealant or lap sealant around the penetration, ensuring a watertight seal.
Use Flashing (Optional but Recommended): For chimneys and other large penetrations, consider using flashing to create a more robust seal. Flashing is a metal or plastic material that is installed around the penetration to direct water away from the roof.
Overlap Correctly: Make sure the felt overlaps the flashing correctly to prevent water from entering.

What Is the Best Type of Felt for a Shed Roof?

The best type of felt for a shed roof depends on your budget and the expected lifespan you’re aiming for. There are two main types:

Bitumen Felt: This is the most common and affordable type. It’s made from a base of organic or fiberglass fibers saturated with bitumen (asphalt). It’s available in various thicknesses and grades.
Modified Bitumen Felt: This is a higher-quality option that offers improved durability and resistance to the elements. It’s made by modifying the bitumen with polymers, which enhances its flexibility, strength, and resistance to UV damage.

For most shed roofs, a good quality bitumen felt will suffice. However, if you want a longer-lasting roof, modified bitumen felt is a worthwhile investment. Always check the product specifications to ensure it’s suitable for flat roofs.

How Long Should Roofing Felt Last?

The lifespan of roofing felt depends on several factors, including the type of felt, the quality of the installation, and the weather conditions in your area. Generally:

Bitumen Felt: Typically lasts 10-15 years.
Modified Bitumen Felt: Can last 15-20 years or more.

Regular inspections and maintenance can help to extend the life of your felt roof.

Can I Put New Felt Over Old Felt?

It is generally not recommended to put new felt over old felt. While it might seem like a quick fix, it can lead to several problems:

Uneven Surface: The old felt may have bumps, wrinkles, or damage, which will be reflected in the new felt.
Poor Adhesion: The new felt may not adhere properly to the old felt, leading to leaks and premature failure.
Trapped Moisture: Moisture can become trapped between the layers of felt, leading to rot and mold.

It’s always best to remove the old felt before applying new felt to ensure a long-lasting and watertight roof. The only exception might be if the existing felt is in very good condition and only has minor imperfections, but even then, it’s a risk. (See Also: how much does it cost to move a shed)

How Much Does It Cost to Refelt a Shed Roof?

The cost of refelting a shed roof varies depending on several factors, including:

Size of the roof: The larger the roof, the more materials and labor will be required.
Type of felt: Higher-quality felt will cost more.
Labor costs (if you hire a professional): Labor costs vary depending on your location and the complexity of the job.
DIY vs. Professional: If you do the work yourself, you’ll only pay for materials. Hiring a professional will add labor costs.

As a rough estimate, you can expect to pay:

DIY: $50-$200 for materials (depending on the roof size and type of felt).
Professional: $200-$500+, depending on the factors listed above.

Getting quotes from several roofing contractors is recommended if you plan to hire a professional.

Final Verdict

Refelting your shed roof is a rewarding DIY project that can save you money and protect your belongings. By following the steps outlined in this guide, you can successfully replace your old, damaged felt and extend the life of your shed. Remember to prioritize safety, use quality materials, and take your time. With a little effort, you can have a watertight and well-protected shed roof.

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Refelting a shed roof is a manageable task for most homeowners. The key is thorough preparation, careful execution, and attention to detail. By taking the time to do the job right, you’ll not only protect your shed but also gain a sense of accomplishment. Now that you have the knowledge, you’re ready to tackle this project and enjoy the benefits of a well-maintained shed!

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How to Refelt a Flat Shed Roof: A Step-by-Step Guide