Replacing shed roof felt is a cost‑effective way to extend the life of a small outbuilding. This guide covers choosing the right felt, preparing the roof, removing old material, and installing new underlayment for durability and weather resistance. It includes step‑by‑step instructions, tool lists, cost estimates, and maintenance tips to help homeowners perform a reliable upgrade with confidence.
Tools And Materials You’ll Need
Start with a complete list to avoid mid‑project trips to the hardware store. Ensure you have safety gear and weather‑appropriate equipment.
- New roofing felt (min. 15–30 lb underlayment, or synthetic/torch‑on options)
- Underlayment adhesive or contact cement (for smooth surfaces)
- Roofing nails or staples with a wide head
- Roofing tape or seam adhesive
- Utility knife, scissors, and a stiff brush
- Chalk line, tape measure, pencil
- Ladder, safety harness (if required), and pry bar
- Chalk line or marker for alignment
- Sealant suitable for exterior use and UV resistance
- Caulking gun and sealant cartridges
Assessing The Shed Roof And Choosing The Right Felt
Evaluate roof size, slope, and existing structure before choosing felt. Consider climate, wind exposure, and any signs of damage. Felt options vary in durability and ease of installation.
- Felt Types: mineral‑modified felt, asphalt roll felt, and synthetics offer different tear resistance and lifetime.
- Underlayment: breathable vs non‑breathable depends on roof design and venting; breathable helps prevent condensation.
- Wind Resistance: reinforced felts with fiberglass or organic mats perform better on high‑wind sheds.
Preparing The Roof Surface
Preparation is critical for a durable installation. A clean, dry surface ensures good adhesion and seam integrity.
- Remove loose shingles, debris, and dirt with a stiff brush.
- Inspect for rot or loose sheathing; repair or replace as needed.
- Ensure gutters and downspouts are clear to prevent water pooling at the eaves.
- Darken any exposed nail heads to prevent corrosion, and seal as required.
Removing Old Felt
Carefully remove old felt to expose a solid base. This reduces the risk of trapped moisture under new material.
- Use a pry bar to lift edges and peel back layers carefully.
- Roll up and dispose of old felt according to local waste guidelines.
- Inspect the roof deck for mold, warping, or rotten boards and repair if necessary.
Installing The New Felt
Follow manufacturer guidelines for the chosen product, paying attention to overlaps, orientation, and fastener patterns.
Overlap And Orientation
Lay felt with an overlap to shed water properly. For most installations, the bottom edge should overhang the fascia slightly and the top edge should contact the eave or drip edge securely.
- Place the first strip with a slight overhang over the eave.
- Overlap seams by 2–4 inches depending on product recommendations.
- Use a chalk line to maintain straight, even rows across the roof.
Attachment And Sealing
Secure the felt with nails or staples as directed. Avoid over‑driving fasteners, which can damage the underlayment.
- Space fasteners evenly along the top edge and at intervals on the field of the sheet.
- Seal seams with adhesive or tape designed for exterior use to prevent lifting.
- Apply sealant at all hips, ridges, and around penetrations to prevent leaks.
Breathable Underlayment Versus Non‑Breathable
Breathable underlayment allows moisture to escape from within the roof, reducing condensation risk in metal or vented sheds.
- Breathable: better for cold climates and roofs with ventilation; may require special fasteners and compatible tape.
- Non‑Breathable: often cheaper and quick to install; suitable for well‑vented or insulated roofs.
Ventilation And Roof Design Considerations
Proper ventilation minimizes moisture buildup, which extends the life of felt and reveals potential deck damage early.
- Ensure soffit vents or ridge vents are clear and functional.
- Check for adequate airflow under the felt, especially on metal roofs or enclosed sheds.
- Consider ridge vent additions if the shed lacks natural ventilation paths.
Waterproofing, Sealing, And Detailing
Detailed waterproofing reduces the chance of leaks at seams, joints, and edges.
- Apply seam tape or liquid seam sealer along all overlaps and dry seams before exposure to rain.
- Seal around penetrations such as vent pipes, chimneys, or skylights with exterior caulk.
- Install drip edges and weatherproofing at eaves to direct water away from the fascia.
Safety And Access Considerations
Work safely at height and follow best practices to prevent accidents.
- Use a sturdy ladder and non‑slip footwear; secure the ladder on stable ground.
- Wear eye protection and gloves; avoid working in wet or windy conditions.
- Have a partner assist for handling large rolls and to assist in case of emergency.
Maintenance And Longevity
Proper maintenance extends the life of shed roofs and reduces future repair needs.
- Inspect after heavy storms for lifted edges or damaged seams; re‑adhere promptly.
- Clean roof surface regularly to remove debris that can trap moisture.
- Consider periodic resealing of edges and seams every 5–10 years, depending on climate.
Cost And Time Estimation
Costs vary with material quality, shed size, and labor. Homeowners can reduce costs with DIY installation.
- Materials: expect $0.50–$2 per sq ft for roll felt; premium synthetics are higher.
- Labor: DIY saves most costs; professional installation adds 1–2 days for typical sheds.
- Total project time: typically 1–2 days for an average shed, plus drying and curing time for sealants.
Environmental Considerations
Choose recyclable or sustainably produced felt when possible and follow local disposal rules for old materials.
- Look for FELT products with recycled content or lower VOCs.
- Dispose of old felt at approved facilities to minimize environmental impact.
Common Issues And Troubleshooting
Anticipate challenges and have remedies ready to avoid delayed timelines.
- Lifting Edges: re‑adhere with seam tape and fasteners; check for wind exposure.
- Warping Or Buckling: verify deck flatness; replace damaged boards before re‑felt.
- Water Stains Inside Shed: inspect eaves and gutters for blockages and reseal seams as needed.