Roof leak? How to find?

[aprilsweetheartrose.]

We seem to have a leak of somekind on the roof. My husband has been in the attic and on the roof to try and find it, but he cant. It only happens after heavy rain and it usually starts to drip ( I can hear it although we cannot see it - except for the mark it makes on the ceiling) after the rain stops, not whilst its pelting down. Hubby can find the place it drips onto but cannot find where the water might be coming in. It all looks fine up there. Any suggestions for tracking this down ( or even a "Solution" which might solve the problem without needing to track it down - short of having a whole new roof that is). Standard Marley tile 1950's construction roof if thats any help - and the leak is somewhere near the chimney but the chimney is not used and the pot is capped so its not coming down inside and the valleys look ok) Thanks for advice in advance.

[Spike]

I had one of these in the distant past. Fortunately a neighbour was a roofer, and a good one, and he found that the chimney flashing had slightly loosened in one place and in heavy rain was letting water into the loft, which is what I could hear as drips but usually after the rain had stopped. The straightforward remedy was to overlap the old flashing with new, set into the mortar, and the problem never returned.

Unfortunately to check yours, someone is going to have to get on the roof and have a careful look at the flashing.

[Chris Green]

Most likely to be something to do with the flashing around the chimney I would think. Use binoculars or take a picture and enlarge it to inspect around the chimney.

[Theo]

Something that can help is to tape a phone or camera to a pole / long drainpipe or similar and set it to record video. Waggle it about on the roof when it's raining and you may be able to see what's happening to the water.

Theo

[Colin Bignell]

If you know anybody with a drone, that would do the job even better.

[Jeff Layman]

As others have said, it's probably the flashing - which might have been loosened by high winds. However, another possibility is cracked or weakened flaunching (that's the mortar which holds the chimney pot onto the brick stack). That can also allow water ingress after rain, but it can take some time to work its way through.

You'll have to get a builder or roofer (or even a chimney sweep) to go up and have a look. Get someone decent to do it; it'll be worth the money in the long run.

[Chris Green]

I was going to say that one of the big advantages of a 'real' camera over a phone camera is that it can have a real telephoto lens on it (I know, some phones are moving that way). My pocketable TZ60 has a 30:1 zoom on it which means one can take really useful pictures from the ground of things like television aerials (and chimneys) to check their condition.

[David]

Perhaps in the mean time put some sort of plastic tray in the loft under where the leak is, to catch the water before it soaks through?

Cheers

Dave R

[N_Cook]

I had similar but eventually twigged where it might be coming from , a long way from the dripping. In the valley between two slopes of roof, so the tile battens ended in mid space. One such unsupported end had warped down over decades, not rotten, that allowed the supported cement tile to droop on one lower edge corner and touch the lead sheet in the valley. Over time with dampness movement of the timbers of the roof or due to temperature or wind, the corner ruptured the lead into a hole and then a tear.

[N_Cook]

Behind the lead sheet is backing boards , the rain running down the upper surface of a backing board, so completely hidden from view/tracing in the attic. As in valley, problem area not possible to view with binoculars , even from the neighbours garden. Later with a ladder , no obvious tear from looking side on at a distance.

[Tim+]

Unless you have any ambitions to climb around on your roof attempting a task you’re not familiar with, get a man in.

Tim

[Theo]

The problem with getting a man in, is they will inevitably turn up when it's not raining. Unless the problem is obvious, they may not be able to find it, especially if the initial cause of the leak is some way away from where the water appears.

Being able to do some preliminary investigation by yourself (without climbing around on the roof) can help establish what the problem is or record some evidence to assist someone you do bring in.

Also, it's always worth checking guttering and drainage, because many 'damp' problems can be caused by faulty gutters or splashback caused by faulty gutters, and not actually a problem with the roof at all. This again is best investigated when it's raining.

Theo

[N_Cook]

In my case the drips emerged in different places, the actual leak being about 10 feet from the fist emergent point. Later drip positions at least showed a rough idea of the water path down the sarking as I originally thought , but eventually found it was travelling down the valley backboard.

Is there a technique to take a hose pipe up a ladder on a dry day and squirt in a grid of positions with someone checking in the attic?

[SH]

A hairline crack in the lead flashing around a chimney stack or in a valley can do this.

DAMIKT!

S.

[AnthonyL]

I was lucky/unlucky with a long lasting ingress into the bedroom brickwork/plaster and all arising from work done some 20year prior when the roof was re-tiled.

The problem was at its worse when there was an easterly wind bringing any rain (the bedroom faced east) so it was not common. The bedroom had a gabled window with lead flashing.

A friend had a portable scaffolding unit and that allowed me to put it up and set the hosepipe on and eventually I found that I only needed it to gently drip on the slate tile immediately above the flashing. Yes, the flashing underneath was flush with the tile, and as most roofers know, water will curl round the bottom of the tile up to about

1/2" on the underside and thus to beyond the reach of flashing and into the roof space. All for the sake of any extra inch or two of flashing or slightly longer roof tiles.

Two sets of "experts" and one builder were unable to detect this.

Hope this is of help to the OP.

[N_Cook]

Lead sheet will creep and its possible there was enough length of lead originally, but sagged over decades, from insufficient support/anchoring ,ie still bad workmanship though.

[Brian Gaff]

Flashing around the chimney is in need of repair. That is the normal case, and it can happen that the water can find a way to somewhere it will run along before it drips. Brian

[Brian Gaff]

I'd imagine it might be best inside the loft so one can see the origin of the drip, then simply track the damp bit along the rafter or other wooden part until you can find its origin, however Flashing is normally the culprit in the first place, and it tracks from there till it drips off. The reason only heavy rain does it is normally it will evaporate before it gets to the accumulation where it can drip.

Mine was caused in a terraced block about 6 months after the neighbours had the internal walls knocked down and replaced by a girder. On assumes the roofs moved slightly making it leak. Brian Brian