We need to repair a leaky gutter and the best way I thought to do this was using Flex Seal(opens in a new window) spray. I bought two cans of it to seal my leaky gutter. I first clean the gutter with a vacuum and applied the Flex Seal spray. Two cans were enough for about 12 linear feet of gutter. I need to buy two more cans to finish the job. I do not know if this will work. As time goes on I will update the video over time in the comments and let you know the status. The Flex Seal was applied in the summer of 2018.
UPDATE: October 2, 2022 the Flex Seal is holding strong! For all those naysayers who called this out in the comments of the video saying that this wouldn’t work, well here’s your proof.
UPDATE: December 2025 the Flex Seal has worn in places and leaks have begun appearing. Six years of solid performance down the Jersey Shore with constant exposure to sun, salt air, and moisure.
UPDATE: February 2026 the gutters have been replaced with new. A decision that wasn’t ours. I would have reapplied more Flex Seal!
Video Chapters
Use these video chapters to navigate throughout the video.
- 0:00 Problem: Leaky Gutter(opens video in a new window at specified time)
- 0:39 Clean out gutter with shopvac(opens video in a new window at specified time)
- 1:05 Apply Flex Seal spray(opens video in a new window at specified time)
- 2:43 Photographing the Hero: Flex Seal(opens video in a new window at specified time)
- 3:04 Summary(opens video in a new window at specified time)
- 3:48 Flex Seal extended the life of my gutters(opens video in a new window at specified time)
How to Use Flex Seal on your Leaky Gutters
Products Used in this Video
- The easy way to coat, seal, protect, and stop leaks fast! Once dry, can be painted any color
- Seeps into cracks and holes. Dries to a watertight, flexible, rubberized coating. Stays flexible and pliable; lasts many years
- Transform and protect virtually everything! Ideal for arts & crafts, projects & hobbies
Amazon.com Price last update on 2026-10-29 - Details(This link opens in a new window)
- THE ORIGINAL MULTI-POSITION LADDER: Little Giant Ladders didn’t just perfect the multi-position ladder—we invented it. Combining multiple ladder types into one, we set a new standard for versatility, strength, and performance, giving you the ultimate tool for any job.
- ONE LADDER. UNMATCHED VERSATILITY: A-frame. Extension. Staircase. 90-degree wall position. One ladder that locks into whatever the job demands. Built for constant change, rugged jobsites and pros who don’t slow down.
- BUILT TO MOVE. BUILT TO LAST: Lightweight aircraft-grade aluminum that's tough enough for heavy jobs but light enough to move quickly, built to resist rust and withstand whatever you throw at it.
Amazon.com Price last update on 2026-10-29 - Details(This link opens in a new window)
- The tools and materials for repairing your leaky gutter on Amazon(opens in a new window)
- Vacuums on Amazon(opens in a new window)
Clean Leaky Gutters
Remove any leaves and debris from the gutter. It is best to wait for the gutter to be dry. Do your best to clean the gutters, which will aid in drying the gutters more quickly. Using your vacuum, like I did in the video with my ShopVac(opens in a new window), vacuum the gutters out. Ensure they are clean and dry. Standing on a ladder and managing a shop vacuum is a huge safety concern. Determine your best path forward. Even consider securing the vacuum from the ladder (in the safest way possible).
Original source of the photo is provided by U Do It, on YouTube channel U Do It(opens in a new window).
Spray Flex Seal
For my gutters, two cans of flex seal covered about 12 linear feet. You can see the coverage of the spray in the video.
Original source of the photo is provided by U Do It, on YouTube channel U Do It(opens in a new window).
Safety First
Please observe safety first behavior. It is your responsibility to ensure that you are performing this activity in a safe manner. If you do not feel comfortable performing this activity it is recommended that you consult with a licensed handyman or gutter specialist. Take all necessary precautions that you can consider. It is best to wear a respirator, gloves and a long sleeved shirt and pants. Enough cannot be said about the safety and awareness in your work area. Remove any obstacles that can be trip hazards. Consult safe operation of a ladder(opens a PDF document in a new window from OSHA) and be aware of your surroundings, such as electric wires or doors that can open. Consider that pedestrians may be injured in the event of something happening.
If you are interested in other U Do It articles like this one you can see them here.
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