Vara
Active member
Title says it all really.
Yes, you have to apply it over and over until the crack has absorbed it. It worked on the multitude of leaks I have (well the small ones).
I find it works very well, but you need to use a lot more than you think you did. I apply enough to leave a meniscus over the area, let that soak in and repeat the process several times until no more will go in. It's fairly permanent but can fail if stressed. This is currently an issue with an area on my cabin roof, and I have as yet not managed to prevent anyone ever standing on it!
Worked for me too, but as has been said, only for very fine cracks and even then, you might need multiple applications until no more goes in.