I've a couple of leaks that have so far evaded detection by everyone who's tried, though I get the feeling that for the most part they've just been up looking for slipped slates rather than secretly broken ones.. I've the additional complication that my roof is sarked with tongue and groove under the battens, so potentially the water could have run quite a long way down a board before it shows itself in the valley gutter. Some of the roof is felted, and some isn't (judging by what was visible through damage we've already repaired)
Just wondering if anyone's come across a good resource on the web (such as a video) that details what to look for/what types of damage can cause leaks, because I'm reaching the point where I'm going to go up and start investigating myself, rather than throw day after day rate trades that can't find anything.
One odd thing about these leaks is that they don't always happen - a few times recently it's absolutely hammered down with rain in very intense bursts and nothing seemed to come through, yet other days when there was a persistent lighter rain all day, it would show. I've also wondered whether it makes a difference which way the wind is blowing as some windy days leak a lot, others don't..
I've the option of borrowing a "camera on a slim stick" kind of device - are these of any help used externally, or would they only really be useful if drilling a hole in the sarking from underneath (no longer an option, alas)
Just wondering if anyone's come across a good resource on the web (such as a video) that details what to look for/what types of damage can cause leaks, because I'm reaching the point where I'm going to go up and start investigating myself, rather than throw day after day rate trades that can't find anything.
One odd thing about these leaks is that they don't always happen - a few times recently it's absolutely hammered down with rain in very intense bursts and nothing seemed to come through, yet other days when there was a persistent lighter rain all day, it would show. I've also wondered whether it makes a difference which way the wind is blowing as some windy days leak a lot, others don't..
I've the option of borrowing a "camera on a slim stick" kind of device - are these of any help used externally, or would they only really be useful if drilling a hole in the sarking from underneath (no longer an option, alas)