Once you’ve found the leak you can make a temporary leak patch from some plywood or shingle and some roofing tar. Use a putty knife to spread the tar into the leaking hole on the inside of your roof. Place the shingle or plywood onto the tar and spread more of the tar around the edges of your patch.Click to see full answer. Similarly, can you repair a roof from the inside?Roof leaks are confusing to diagnose. However, when it is not practical to climb up on the roof to fix a leak, such as during the winter months, you can repair a leaky roof temporarily, from the inside, if you can determine where the leak is occuring from the underside of your roof.Beside above, how much does it cost to repair a roof leak? Most home owners spend between $300 and $1,100 for a roof repair, or an average of $650 per repair call. Typically, a job is to repair leaks. Seal the leak, replace shingles, seal the shingles. If there is a small area and few shingles being repaired, it will likely be on the low end, or as little as $150. Furthermore, how long can you leave a leaking roof? 20 to 30 years Can you use flex seal on roof?Reapply until all cracks and holes are completely filled. Inspect the roof and apply more as needed. For immediate repair, consider also using Flex Tape or Flex Glue. These can be applied in wet conditions, and can help prevent damage when you are unable to apply Flex Seal or Flex Seal Liquid.