Roofing underlayment serves as a critical secondary water barrier, protecting structures from moisture infiltration due to ice dams, wind-driven rain, and other weather-related risks. The Titanium PSU30 is a high-performance self-adhered underlayment designed for steep and moderate slope roofs. It is specifically engineered for durability, ease of installation, and compatibility with a wide range of roofing materials. This article provides a detailed, step-by-step guide to installing the Titanium PSU30 underlayment, along with critical considerations for safety, storage, and best practices. All information is derived directly from official installation guidelines and technical specifications provided by the manufacturer and authorized sources.
Overview of the Titanium PSU30 Underlayment
The Titanium PSU30 is a modified rubberized asphalt underlayment with a self-adhering membrane and a patented Sure-Foot® nodular surface that enhances walkability on steep slopes. This feature is particularly beneficial for installers working in challenging conditions, such as wet or dusty environments. The product is part of the Owens Corning Total Protection Roofing System®, which integrates high-performance materials for enhanced durability and weather resistance.
Key features include:
- Self-adhering membrane for secure attachment without the need for additional adhesives or fasteners (in most cases).
- Synthetic polymer surface that is both slip-resistant and resistant to temperature fluctuations.
- Compatibility with a variety of roofing materials, including metal, tile, shakes, slate, and both asphalt and synthetic shingles.
- Recommended slope range: 2:12 or greater for most applications.
- Lifespan and performance are supported by a lifetime limited warranty, subject to terms and conditions outlined in the official warranty documentation.
Pre-Installation Considerations
Before beginning the installation of the Titanium PSU30, several preparatory steps must be taken to ensure a successful and long-lasting application.
1. Verify Roof Deck Material
The underlayment is approved for use over a wide range of roof deck materials, including:
- Plywood
- Oriented strand board (OSB)
- Fire-rated treated plywood
- Polyisocyanurate foam insulation board
- Metal decks (e.g., galvalume steel)
- 30 lb felt underlayment
- Pre-wrapped roof sheathing
- DensDeck and USG Securock roof boards
For gypsum-based roof boards such as DensDeck and Securock, it is recommended to use an appropriate primer or adhesive when installing at temperatures 40°F or below. For all other deck types, no primer is required as long as the surface is clean and dry.
2. Install Drip Edges
Prior to laying the underlayment, metal drip edges should be installed along the eaves (bottom edges) of the roof. This helps direct water away from the roof deck and prevents moisture-related damage. The drip edge should be secured first, followed by the underlayment, which should extend slightly past the drip edge flashing.
At the rake edges (sides of the roof), the underlayment should be installed first, flush with the edge, and the drip edge should overlap the underlayment when installed.
3. Surface Preparation
The roof surface must be clean, dry, and free of debris before installation. Any existing underlayment should be removed unless required by local building codes. The underlayment should not be installed over buckled, wrinkled, or distorted areas of the roof deck, as it must lay flat and smooth for optimal performance.
4. Temperature and Environmental Conditions
Installation should occur within the ideal temperature range of 40°F to 100°F. Below 40°F, the underlayment may not adhere properly, and above 100°F, the release liners may stick to the material. Additionally, the underlayment should be stored at room temperature in a cool, dry, and well-ventilated area, away from direct sunlight and not above 90°F for extended periods.
5. Safety Precautions
Underlayment surfaces can be very slippery, even when dry. Installers must use appropriate fall protection gear and follow OSHA safety guidelines to prevent accidents. Due to the complexity and critical nature of the installation, it is strongly recommended that only experienced, professional roofing contractors perform the work.
Step-by-Step Installation Process
1. Measure and Cut the Underlayment
The underlayment should be unrolled and cut into manageable lengths of 15–20 feet for easier handling and installation. Each section should be allowed to relax and flatten out for 3–5 minutes before being re-rolled and installed.
2. Apply the First Course
Begin the installation at the lowest point of the roof and work upward. The first course should be laid along the eaves, with the bottom edge extending slightly past the drip edge. Ensure that the underlayment is smooth and free of wrinkles or distortions.
3. Overlap and Seal End Laps
Where two horizontal courses meet end-to-end, the underlayment should be overlapped by a minimum of 6 inches. Heavy hand pressure or a roller should be applied across the entire overlap area to ensure a secure seal. Adjacent courses should have their end laps staggered by at least 6 feet to prevent water from tracking through the seams.
4. Handle Low Slope Applications
For low slope applications (1/2:12 to 2:12) with standing seam metal panels, special considerations apply. All end laps between underlayment courses should be at least 6 feet apart, and the end laps themselves should be a minimum of 6 inches wide. Additionally, a 6-inch wide bed of ASTM D4586-compliant roof cement should be applied at the end of the underlying piece. The overlapping piece is then set into the cement and firmly pressed into place.
5. Install in Valley Areas
For roof valleys, the underlayment should be cut lengthwise to ease installation. The full width of the underlayment should be left intact and extended 18 inches on each side of the valley. The underlayment should be laid starting from the center of the valley and working outward, pressing it firmly into place. A minimum overlap of 4 inches should be maintained if needed.
6. Allow for Adequate Headlap
At the roof peak, the underlayment should be extended at least 6 inches past the ridge, ensuring it laps over the courses from the opposite roof slope. This helps prevent water from seeping through the peak and into the roof structure.
7. Cover Promptly
Once installed, the underlayment should be covered by the final roofing material (e.g., shingles, tiles) as soon as possible, with no more than 180 days of exposure recommended. Prolonged exposure to the elements can compromise the performance of the underlayment.
Post-Installation Best Practices
1. Ventilation
The Titanium PSU30 acts as a vapor barrier, which means that adequate attic ventilation is essential to prevent moisture buildup. Installers must ensure that ventilation complies with local building codes and is sufficient for the specific roof design.
2. One-Layer Installation
The underlayment should be applied as the single layer of underlayment directly over the roof deck. It should not be installed over any existing underlayment unless required by local codes.
3. Avoid Vertical Applications
The Titanium PSU30 is an exterior roofing underlayment only and should not be used on vertical wall surfaces or other non-roof applications.
4. Monitor Climate Conditions
Installation should be avoided during extreme weather conditions, such as heavy rain, snow, or high winds. These can interfere with the adhesion process and compromise the integrity of the underlayment.
5. Adhere to Local Codes
While the installation guidelines provided are based on general best practices, it is essential to consult and comply with local building codes and roofing regulations. These may vary depending on the region and can affect everything from material selection to installation techniques.
Critical Tips and Precautions
To ensure the long-term performance and effectiveness of the Titanium PSU30 underlayment, the following tips and precautions should be strictly observed:
- Use appropriate fall protection gear and follow OSHA safety guidelines, especially when working on steep slopes.
- Do not attempt a DIY installation unless you have significant roofing experience. Hire a professional contractor for the best results.
- Ventilate attic spaces to prevent moisture buildup, as the underlayment acts as a vapor barrier.
- Avoid installing the underlayment over wrinkled or distorted areas of the roof deck.
- Never exceed 180 days of exposure to the elements after installation.
- Use the underlayment only on roofs and not on vertical surfaces or other areas.
Conclusion
The Titanium PSU30 is a high-performance underlayment that provides reliable waterproofing protection for a wide range of roofing applications. Its self-adhering design, slip-resistant surface, and compatibility with various roofing materials make it a preferred choice for both residential and commercial projects. However, successful installation requires careful planning, adherence to temperature and environmental guidelines, and strict compliance with best practices and local building codes.
By following the step-by-step process outlined in this guide, installers can ensure that the underlayment is applied correctly and efficiently. It is crucial to prioritize safety, use the right tools and techniques, and allow sufficient time for the underlayment to adhere properly. Ultimately, the Titanium PSU30 serves as a critical component of the roofing system, offering long-term protection against water intrusion and contributing to the overall durability and performance of the roof.