The Invisible Leak!

[chuckalicious]

Ok, this one is driving me nuts. I live in an old Victorian property, with an original slate roof. The roof is in fair condition, and is dry other than a very small section (about 30cm x 40cm) at the very top/apex of the roof on one side. This section gets wet (varying degrees depending on type of rain). This has clearly been an issue since before we bought the place as you can see where they previous owners have replastered after water damage.

I have had a roofing company up there who removed a tv cable that someone had run from the aerial under a slate and into the loft for a tv, which they thought might be tracking the water. Sadly, this has only made it worse, and the wood now gets very wet, instead of slightly wet.

They have been up twice, and have stated that they cannot see any bad flashing or slates. What confuses me is this problem starts at the very top of the roof (ie where the 2 sloping sides meet at the top, one side is wet from the very top) so to me it suggests the flashing or very top row of slate is duff. The roofing company claim that if they can't see anything on their next visit up (hopefully today or tomorrow) we'll either need to get someone else to look at it, or get them to strip down that section and relay it to make sure it is sound.


Thoughts on this? First of all, if the wet starts at the very top of the roof, surely the problem has to be at the top yes? Gravity would pull any water getting in down and it would present itself as damp patches or drips coming through cracks in the wood yes? Even if the water was wind driven, the problem would still have to be close to the very top I would have thought.

So if they can't find the problem and have to strip that area back, based on the sizes I'm suggesting, roughly, are we talking £500 or £5000?

Thanks all.

 

[noseall]

it sounds as if there may not be adequate lap at the ridge and that the ridge course* may not be weathering.



*the course of tiles directly beneath the ridge.

 

[chuckalicious]

Update:

Had the roofers back round, and I had someone in the house at the time to ensure they were looking in the right place, and had given them diagrams, measurements etc as to exactly where the issue was. After they looked at those, and in the loft to get their bearings, they admitted the past 2 times they have been out, they have been looking in the wrong place, hence not seeing the problem. When directed to the correct place, they found a crack in the flashing/ridge of the roof, a dent in said ridge, running directly into a broken slate. So, the crack was letting water in, and the dent was channeling water directly into the cracked slate. When they removed the broken slate, they found that the wood was soaked, so they had the right bit. So, all is repaired now, and it rained last night, and the area stayed dry, so fingers crossed it has done the trick (we thought that last time remember).

So the moral of the story is 2 fold.

1. Don't assume that the person that comes to look at the problem initially will pass on the correct info to the people doing the work

2. Be there when they are doing the work.

 

[chuckalicious]

Damn it!

Rained last night, and the same area got wet again. Not as wet, but still wet.

I'm going to try a different company and see if someone different can get the job done.

However, to ease my worry (hopefully), how bad is it to let the wood get a little wet? I don't know how long this has been going on for (only had the house 4 months, it's well over 100 years old). I don't want the wood to rot, but have no idea how long it takes for permanent damage to occur. Seeing as it's so hard to get the thing fixed, I need to know whether or not I'm damaging my roof by letting it get wet while I try and get it fixed.....

 

[Nige F]

Iwouldn`t worry unduly because the wet area is visible and presumably ,ventilated in the roofspace.........getting it fixed is the worry

 

[JohnD]

Have you sat in the loft with your torch on a rainy day yet?

Water will run along the structure and can drip off a long way from the leak.

 

[chuckalicious]

Yes, I sat in the loft space with a torch (Gollum style) when it rained last night. It's still coming in at the very top of the roof, although not as widespread. There is a nail that comes through one of the boards a few mm from one of the vertical beams (don't know what they are called) and the water is coming in there. Because it's so close to the vertical beam, it's making that damp as well and the water slowly creeps down that.

 

[Nige F]

Rafters and the boarding across them is sarking....if that`s what you`ve got? so the nail must`ve missed the rafter when the sarking was fitted ?........then the slates..fixed...sometimes without more battens when ther`s sarking sounds complex.......but I`m pretty sure that`s how it`s done in Scotland .....different here in sunny SE so the water`s getting under the ridge and finding a nail hole.maybe ....think a pic. of roof/ridge might be useful

 

[chuckalicious]

I'll see what I can do. Funny thing is, I stuck my head into the loft this morning, it's been raining all night, not heavily, but constantly, and the roof was bone dry..... I'm sure it's taunting me!

But I'll try and take a shot of the roof from the nearest skylight (not a chance in hell I'm going onto the roof!).

 

[Nige F]

skylight is good .......I was expecting one from ground level

 

[chuckalicious]

Okay, go here to view the pics:

http://www.flickr.com/photos/35652586@N00/

The roof ones aren't too good I'm afraid, it's too far from the ground to get a good shot (it's almost dark by the time I get home), and the way the skylight is I had to just hold the camera out it and point.... but both pics show the skylight by the pipe sticking out. The leak is at the top of the roof, about 20cm to the right of the skylight in the image.

If you look at the internal pics, you'll see the wet patches and how close they are to the roof (the screws only go in about 3mm each, just enough to hold the string to tease the water into a bucket). The width between each vertical beam is 38cm so you can get an idea of size. The knot in the wood you see near the very top also gets wet, as dose the nail sticking through right in the corner. So it's clear it's coming from the very top, or at least it's getting in there and lower down, but I'm guessing (and hoping) it's just getting in at the top and finding the first big gap to get through, which is where you see the main wet bit. Just to the right of the internal photo is the little skylight I mention on the outside, so you can get your bearings.

Hope that's helpful.

 

[Nige F]

is that lead on the ridge ...lumpy old slates too ..guessed right about the sarking boards tho` ...............yes, you said it was lead flashing on the ridge , well that needs inspecting , maybe lifting and checking under for more broken slates .....worst case it needs re doing as maybe the wind is blowing rain up+under the flashing/ridge roll.......which wouldn`t happen with a cemented on ridge tile ........got any old-school leadworking plumbers up there?

 

[chuckalicious]

Old slates yes... this place was built in 1877 and it's an original roof, the whole terrace is the same. Toe be fair the entire rest of the roof is bone dry, it's just this one section.

Assuming the ridge needed replaced, how much does something like that cost roughly? Are we talking a few 100 or a lot of 100s?

*EDIT* sorry lynda

_____________________________________
lynda, moderator

Please note forum rule 9

 

[chuckalicious]

Not sure how this happened but one of the photos was marked as private so only I could see it. If you go back in you should see 4 pics, 2 internal, as opposed to the 1 you probably saw when you last looked. The second one simply lets you see how close to the top the first wet bit starts

 

[chuckalicious]

Woke up this morning and it was chucking it down. Harder than it has been for a good few weeks.

Thought I'd stick my head up into the loft to see how wet the roof was. Bone dry.

Went outside and there was no wind. So, I'm guessing that it's now only wind driven rain that's making the roof wet.

This would suggest that simply looking at the roof won't find the problem, either a strip down of that area, or a replacement of the ridge would be in order?

Agree?