Finishing the edges of a felt roof is a critical step for ensuring its longevity, weather resistance, and aesthetic appeal. It primarily involves securing the felt layers to prevent water ingress and provide a neat, durable edge.
Why Edge Finishing is Crucial
Properly finishing the edges of your felt roof is essential for several reasons:
- Waterproofing: The primary goal is to prevent water from seeping underneath the felt, which can lead to timber rot, structural damage, and leaks.
- Durability: Secure edges prevent the felt from lifting, flapping in the wind, or tearing, significantly extending the roof's lifespan.
- Aesthetics: A well-finished edge provides a clean, professional look to the roof, enhancing the overall appearance of the structure.
- Pest Prevention: Sealed edges can help deter insects and small animals from nesting under the roofing material.
Step-by-Step Guide to Finishing Felt Roof Edges
Finishing the edges typically involves creating an overhang, securing it, and often adding a protective trim.
1. Preparing the Roof Edge
Before laying the felt, ensure the roof deck edges are clean, dry, and free from debris. Any rough spots or old fixings should be removed.
2. Overhang and Folding
When laying the felt, allow for an adequate overhang beyond the edge of the roof deck. This overhang is crucial for creating a drip edge and securely sealing the roof.
- Standard Overhang: Typically, an overhang of 50-75mm (2-3 inches) is recommended.
- Folding: The felt should be carefully folded down over the edge of the roof deck. For a shed roof, this often means folding it down over the fascia board. Ensure the fold is sharp and tight against the edge.
3. Securing the Felt with Adhesive/Sealant
This is a vital step in preventing water from compromising the roof's integrity.
- Adhesive Application: Apply a suitable roofing felt adhesive or sealant generously to the underside of the felt where it wraps over the edge and against the fascia board or trim.
- Pressure: Press the felt firmly onto the adhesive to ensure a strong bond and eliminate air pockets. This adhesive or sealant application at the edges and any overlaps is critical to prevent water from seeping underneath the felt.
- Nailing: After applying adhesive, the felt can be further secured using large-headed felt nails (galvanised for corrosion resistance). Place nails at regular intervals (e.g., every 10-15cm or 4-6 inches) along the edge, just above the fold line, ensuring they penetrate securely into the timber.
4. Applying Edge Trim or Battens
For a neat and more robust finish, it's common to add timber battens or metal trim along the edges.
- Timber Battens: Often, timber battens (sometimes called fascia boards or verge boards) are installed over the felt where it folds down the edge. These battens are typically secured with screws or nails into the roof structure. They serve to:
- Hold the felt firmly in place.
- Protect the felt edge from wind uplift and physical damage.
- Provide a clean, finished appearance.
- Metal Drip Edges: Pre-formed metal drip edges or trims can also be used. These are designed to guide water away from the fascia and provide a very durable edge. They are usually installed under the felt at the eaves (bottom edge) and over the felt at the verges (side edges) before the final felt layer is applied, then nailed into place.
5. Handling Corners
Corners require special attention to ensure full waterproofing.
- Overlap and Fold: At corners, the felt from one edge should extend beyond the corner to overlap the felt from the adjacent edge.
- Cutting and Sealing: Carefully cut the felt at the corner to allow for a neat fold. Apply extra adhesive or sealant to fully encapsulate the corner, ensuring no gaps.
- Corner Protection: Corner trims or specially cut timber battens can be used to reinforce and protect these vulnerable points.
Essential Materials and Tools
To effectively finish felt roof edges, you will need:
| Material/Tool | Purpose |
|---|---|
| Roofing Felt Adhesive | To bond the felt layers and secure edges, preventing water ingress. |
| Large-Headed Felt Nails | For mechanically securing the felt to the timber deck and edges. |
| Timber Battens/Trim | To provide a neat, protective, and secure outer edge finish. |
| Hammer | For nailing felt and battens. |
| Utility Knife/Blades | For precise cutting of felt. |
| Tape Measure | For accurate cutting and overhang measurements. |
| Caulking Gun (if using tubes) | For applying sealant. |
Safety First
When undertaking any work on a roof, always prioritize safety. This includes using appropriate ladders, scaffolding, or fall protection, especially when working at height. Ensure stable footing and be aware of your surroundings to prevent accidents.
Best Practices for Longevity
- Cleanliness: Always work on a clean, dry surface.
- Generous Adhesive: Do not skimp on adhesive, particularly at edges and overlaps, as this is your primary waterproof barrier.
- Proper Nailing: Ensure nails are driven straight and flush, without puncturing the felt excessively.
- Inspect Regularly: Periodically check the roof edges for any signs of lifting, damage, or wear, and address them promptly.
- Quality Materials: Use high-quality roofing felt, adhesives, and fixings for maximum durability.
By carefully following these steps, you can ensure the edges of your felt roof are durable, weatherproof, and aesthetically pleasing for years to come.
