The decision to roof over a skylight is common during roof replacements or when a skylight has failed. This article covers why homeowners might choose to cover a skylight, the risks involved, and the best methods to ensure a watertight, durable result. It explains the steps, materials, and common mistakes, helping readers make informed choices that protect the interior and preserve home value.
Why People Consider Roofing Over A Skylight
Roofing over a skylight typically happens during a roof replacement or when a skylight is damaged beyond repair. The main motivations include reducing ongoing maintenance, lowering installation costs, and simplifying roof lines. However, this option eliminates natural light and ventilation provided by the skylight. Homeowners should weigh the trade-offs, especially if the skylight is in a high-traffic area or a room with limited daylight.
Key considerations include structural support, potential for condensation, and the impact on resale value. If the decision is final, planning for proper flashing and weatherproofing is essential to prevent water intrusion and ensure long-term durability.
Preparation And Planning Before Roofing Over
Thorough assessment is critical. Inspect the skylight frame for rot, leaks, or damage that could transfer to the new roof. If the frame is compromised, it may need removal and proper sealing instead of merely covering. A professional inspection helps determine whether to keep the skylight, remove it, or seal it shut.
Secure approvals if required by local codes or HOA rules. Ensure rooftop access is safe and that fallen debris won’t contaminate the living space. Consider whether there will be any residual daylight loss in rooms previously served by the skylight.
Best Methods For Roofing Over A Skylight
Several methods exist, each with different implications for airflow, light, and water management. The most common choices are to seal the skylight and install a flat roof over it, or to replace the skylight area with a continuation of the new roof plane using proper flashing. The chosen method should align with the roof type, slope, and climate.
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- Flashing Integration: Integrate proper step and counter-flashing around the skylight perimeter to direct water away from the joint. Use corrosion-resistant materials compatible with the roofing system.
- Decking Considerations: Ensure the roof deck is solid, dry, and free of soft spots. Any warped or rotten wood should be replaced to support the new roof plane.
- Ventilation And Condensation Control: In some cases, sealing the skylight can trap humidity. If possible, maintain some venting through the attic or include ridge/soffit vents to balance moisture.
- Light And Aesthetics: If daylight is essential, consider alternative solutions such as skylight replacements elsewhere, or solar tubes in adjacent areas to preserve some natural light penetration.
Step-By-Step Process For Roofing Over A Skylight
Note: This is a high-level guide. Always follow manufacturer instructions and local building codes. Hire a licensed roofer for critical safety and warranty reasons.
- Hire a professional to confirm feasibility and obtain permits if required.
- Inspect and repair the underlying roof deck where the skylight sits, replacing rotten or damaged boards as needed.
- Remove the skylight frame and seal the opening, or prepare the area for a continuous roof plane if the skylight remains in place.
- Install appropriate flashing around the skylight opening, using durable materials and compatible sealants to prevent water infiltration.
- Apply roof underlayment and extend it over the skylight area to ensure a seamless barrier against moisture.
- Install the new roofing material, ensuring the edge details meet the flashing for a tight seal.
- Perform a thorough inspection for gaps, nail heads, or puckering shingles and seal any penetrations with approved sealants.
Common Mistakes And How To Avoid Them
Common issues include improper flashing installation, insufficient deck ventilation, and attempting to seal a skylight without addressing underlying damage. These mistakes can lead to leaks, mold, and costly repairs. A few practical tips help avoid problems:
- Do not Skip Flashing: Proper step-and-counter flashing is essential around the skylight perimeter.
- Avoid Over-Insulating On The Surface: Over-tightening can cause warping or cracking in some materials. Follow manufacturer guidelines for expansion gaps.
- Check For Condensation: If the space beneath is prone to humidity, add ventilation or adjust insulation to reduce moisture buildup.
- Maintain Roof Drainage: Ensure gutters and downspouts are clear so water flows away from the skylight without pooling around the seam.
Materials And Flashing Options
Choosing the right materials affects durability and compatibility with the existing roof. The table below summarizes common options and their benefits.
| Material | Use Case | Pros | Cons |
|---|---|---|---|
| Metal Flashing (Copper/Aluminum) | Skylight perimeter | Durable, corrosion-resistant; excellent water shedding | Requires skilled installation; cost varies |
| Self-Adhered Membrane | Underlayment around skylight | Strong waterproof barrier; easy to apply | Surface preparation critical |
| Roofing Granules Or Shingles | Visible roof replacement around skylight | Blends with rest of roof; cost-effective | Need precise alignment to prevent leaks |
| Sealants And Caulks | Joints and fasteners | Flexibility; sealing gaps | Needs maintenance; degrades over time |
Inspection And Long-Term Maintenance
Once the roof over the skylight is completed, regular maintenance is essential. Schedule an annual inspection after the first full season of weather exposure. Look for peeled flashing, loose nails, or signs of moisture inside the attic. Clean gutters to prevent water backup near the skylight area. If any condensation or leaks appear, address them promptly to avoid structural damage.
Document warranty terms with the roofing contractor. Keep records of materials used, flashing specifications, and inspection notes. This information helps with future roof work and potential resale value.