Roof valleys are highly vulnerable to leaks and water damage. Thus, correctly installing a roof valley seal is essential to protect your home from potential water infiltration and ensure a long-lasting, leak-free roof.

In this comprehensive guide, we’ll walk you through everything you need about roof valley seals and how they can save you from costly water damage. Let’s dive in!

What is a Roof Valley Seal?

A roof valley seal is a protective material or barrier installed in the intersection of two roof sections (aka, a roof valley). The polyurethane foam strip is soaked in bitumen, a sticky and viscous substance that forms a waterproof layer. When fixed on either side of the iron roof valley or under the tile, it creates an effective barrier that funnels water into the rain gutter and off the roof. In short, roof valley seals are crucial in preventing water leaks in your home.

Why Install Roof Valley Seals

Aside from leak prevention, roof valley seals can also bring other benefits, including:

  • Increased Roof Lifespan. By protecting vulnerable roof valleys, seals contribute to the longevity of the entire roofing system, reducing the need for premature repairs or replacements.
  • Structural Integrity. Roof valley seals ensure that water is channelled away from critical roofing joints, maintaining the structural integrity of the roof and preventing wood rot or damage to the underlying structure.
  • Weather Resistance. These seals provide a robust barrier against harsh weather elements, including heavy rain, storm, drought, and snow, safeguarding the roof from rust, corrosion, and other weather-induced wear and tear.
  • Energy Efficiency. Properly sealed roof valleys enhance insulation and reduce energy loss, improving energy efficiency and potential cost savings on heating and cooling.
  • Increased Property Value. Roof valley seals are increasingly becoming more popular. In fact, its market is expected to grow by 7.1% by 2030. By installing them, your property’s market value will rise as well.
  • Mould and Mildew Prevention. Roof valley seals minimise the risk of mould and mildew growth by preventing water intrusion, promoting a healthier indoor environment.

Should Roof Valleys Be Sealed?

Roof valleys should always be sealed. As mentioned above, they’re crucial for preventing water infiltration, protecting against leaks, and maintaining the roof’s structural integrity. Filling roof valleys also enhances the roof’s longevity, reduces the risk of damage, and contributes to a durable, leak-free roofing system, providing numerous long-term home ownership benefits.

Installing New Roof Valley Seals

Whether you have a brand-new roof or are replacing old and worn-out seals, installing new roof valley seals requires careful attention to detail. So in this section, we’ll delve into the materials commonly used for roof valley seals and the steps involved in their installation.

Common Materials Used as Roof Valley Seals

  • Self-Adhesive Membranes. These peel-and-stick materials with a bituminous or synthetic rubber base provide excellent adhesion and waterproofing properties.
  • Metal Flashing. Metal roof valley seals are typically made of aluminium, copper, or galvanised steel, offering durability and long-lasting protection against water intrusion.
  • Rubber Seals. Rubber roof valley seals are flexible and weather-resistant, providing a reliable barrier against water and debris.
  • Woven Fabric Seals. Made from reinforced fabric, these seals are woven together to create a watertight barrier in the roof valley.

Steps to Properly Install Roof Valley Seals

  • Prepare the Roof Valley. Start by inspecting the roof valley for any damage or debris. Clear the area of leaves, dirt, and old sealant to create a clean surface.
  • Measure and Cut the Seals. Accurately measure the length of the roof valley and cut the seal material to fit. Use sharp tools and take care to ensure precise measurements.
  • Choose the Seal Type. Select the appropriate seal type based on your roof material, climate, and preferences. Options include self-adhesive membranes and metal flashing (see list above). Just make sure the product you use is fire tested and complies with all relevant Australian standards.
  • Apply the Seals. Make sure you’re wearing appropriate safety gear, like knee pads.
  • For self-adhesive membranes, peel off the backing and carefully apply the seal along the roof valley, starting from the top and working your way down.
  • For metal flashings or rubber seals, use roofing nails or adhesive to attach them to the roof valley. This will help ensure a tight and secure fit.
  • For woven fabric seals, weave them together at the roof valley edge, securing the woven sections with nails or staples.
  • If you have roof tiles, remove them before installing the seals. However, if you can access the valley beneath by hand, you can manually place the seal without removing them.
  • Ensure Overlapping. Properly overlap the seal sections to create a continuous and watertight barrier. Follow the manufacturer’s instructions for the recommended overlap distance.
  • Seal Joints and Intersections. Apply roofing cement or sealant to any gaps or spaces at the joints and intersections of the roof valley, providing extra protection against water infiltration. You can also try acrylic polymer roof paint.
  • Inspect and Adjust. Once the installation is complete, inspect the entire roof valley seal for potential gaps, loose sections, or imperfections. Do the water hose test to promptly check for leaks and address any issues.
  • Maintain Regularly. Periodically inspect and maintain the roof valley seals to ensure their effectiveness and prolong their lifespan, protecting your roof from potential water-related problems.

Maintaining and Repairing Roof Valley Seals

Roof valleys are vulnerable to wear and tear from weather exposure and debris accumulation. Through regular maintenance, you can prevent minor issues from escalating into more significant problems. Here are essential tips for maintaining and repairing roof valley seals:

  • Inspect Regularly. Schedule periodic roof inspections to assess the condition of the seals and identify any signs of wear, damage, or deterioration.
  • Clear Debris. Keep the roof valley free from leaves, twigs, and other debris that can impede water flow and cause seal damage.
  • Fix Gaps and Cracks. Check for gaps, cracks, or separations in the sealant or seal material. Promptly fill them with compatible glue to maintain a watertight barrier.
  • Replace Damaged Seals. If you notice extensive damage or aging signs, consider replacing the damaged sections or the entire roof valley seal with new, high-quality materials.
  • Inspect Flashing and Nails. Make sure that the metal flashing and roofing nails used to secure the seal are in good condition and adequately fastened.
  • Reapply Sealants. Over time, roofing cement or sealant may deteriorate. Reapply a fresh layer to reinforce the seals and enhance waterproofing.
  • Address Water Stains. Water stains on ceilings or walls might indicate a leak in the roof valley. Investigate and repair the seal promptly to prevent further water intrusion.
  • Call a Professional. Periodically engage an expert roofer to thoroughly inspect and address any underlying issues before they worsen.

Hiring a Roofing Contractor for Roof Valley Seals

While DIY installations can save you money, entrusting the installation, maintenance, or repair of roof valley seals to a professional roofing contractor can sometimes be the better course of action. Here’s why:

  • Expertise. Professional roofing contractors have the necessary knowledge and skills to evaluate the condition of your roof valley seals and determine the best course of action.
  • Quality Workmanship. Hiring a professional ensures that the installation or repairs will be done to high standards, minimising the risk of leaks or other issues.
  • Quick Installation. Professionals have the right tools and equipment to complete the job efficiently, saving time and effort.
  • Safety. Roofing projects can be dangerous, especially if you are not experienced in working at heights. Hiring a professional ensures the safety of both yourself and the workers.

Tips When Looking for a Professional Roofer

  • Do Your Research. Conduct thorough research online, read reviews, and seek recommendations from friends, family, or neighbours who have recently had roof work done. Look for contractors with positive feedback and a solid reputation.
  • Check for Qualifications. Check for the contractor’s licenses, certifications, and insurance coverage. Choose a roofing professional with extensive experience installing roof valley seals and a proven track record of successful projects.
  • Choose a Local Expert. Opt for a local roofing contractor familiar with regional weather conditions, your area’s building code, and other regulations. Local contractors are more accessible for follow-up or warranty-related issues.
  • Compare Rates. Obtain multiple price quotes from different contractors. A reputable roofing professional should offer a free, detailed estimate outlining the work scope, materials, and costs involved.
  • Ask About Insurance and Warranties. Inquire about the warranties and guarantees provided by the contractor for both the materials and labour. A reliable contractor stands behind their work and provides assurances for customer satisfaction.

Insurance Coverage and Warranties for Roof Valley Seals

Protecting your home from potential water damage and leaks is a top priority in Melbourne and other parts of Australia. Thus, understanding insurance coverage and warranties for roof valley seals is crucial. Here’s what you need to know:

  • Home and Contents Insurance. Roof valley seals are typically covered under standard home and contents insurance policies. Suppose your roof sustains damage from storms or falling trees. In that case, the insurance business should cover the repair or replacement, including the roof valley seals.
  • Product Warranty. Manufacturers also offer warranties on their roof valley seal products. Their policies may vary in coverage and duration, so it’s essential to carefully review the terms and conditions to understand what is included and for how long.
  • Workmanship Warranty. Reputable roofing contractors in Australia also provide warranties covering the installation and labour for roof valley seals. This ensures that the contractor will rectify any installation errors or defects.
  • Maintenance and Regular Inspections. However, insurance companies and warranties usually don’t cover wear and tear or damage from a lack of maintenance. Regular inspections and upkeep are vital to maintaining the effectiveness of roof valley seals and ensuring coverage for potential claims.

Tips to Fully Enjoy Insurance and Warranty Coverages

  • Read the Fine Print. Familiarise yourself with the details of your home insurance or warranty contract, ensuring it covers roof valley seals for potential damages caused by covered events.
  • Keep Records. Maintain documentation of maintenance activities and inspections, as they may be required for claims. Keep all related documents, including warranty certificates, receipts, and contracts.
  • Schedule Inspections. Arrange regular inspections with professional roof service providers to identify potential problems early and address them promptly.
  • Keep the Insurance and Warranty Provider Posted. In the event of damage, notify your insurer or warranty provider promptly and follow their process to fully enjoy their perks.
  • Comply with Maintenance Guidelines. Adhere to any specific maintenance guidelines the material manufacturer or contractor outlines to retain insurance or warranty benefits.

Energy Efficiency and Insulation with Roof Valley Seals

Roof valley seals not only waterproof your roof but also impact your home’s energy efficiency and insulation. They reduce the workload on your heating and cooling systems by preventing air leakage and heat loss. This allows you to save on energy bills and keep your home well-insulated.

Tips to Improve Energy Efficiency and Insulation

  • Choose High-Quality Seals. Opt for high-quality, energy-efficient roof valley seals with good insulation properties to minimise heat transfer and enhance energy performance.
  • Get Additional Insulation. Add extra insulation in the attic and roof valley area to improve energy efficiency and reduce heat loss.
  • Seal Gaps and Air Leaks. Check for gaps or air leaks around the roof valley seals and seal them with weatherstripping or caulk to prevent energy loss.
  • Enhance Attic Ventilation. Ensure proper attic ventilation to regulate temperature and humidity levels, optimising energy efficiency.
  • Consider Roof Coatings. Getting a roof coating with reflective properties can improve energy efficiency by reflecting sunlight and reducing heat absorption.


Don’t overlook the significance of roof valley seals in safeguarding your home against water damage and improving energy efficiency. By following the comprehensive guide above, you can ensure a successful installation of roof valley seals, enhance your roof’s longevity, and enjoy a secure, leak-free, and energy-efficient roofing system. Take the necessary steps now to protect your home and enjoy peace of mind for years to come.