guttering problem and resulting wet bricks

Oct 04, 2005 8 Replies

Hi people



Not strictly d.i.y., but I am feeling the need of some background understanding of brick and guttering and suchlike...



Around 20 August or so, there were a couple of heavy rainstorms, and we discovered that the guttering at the front of the house had developed a problem.



There is one two-storey downwards pipe which serves the guttering around the top of the bay windows of both our house and next door. The water from each roof discharges onto the bay windows, so this pipe is supposed to take all the water from the front half of both roofs, about 16 square metres per house. Pipe diameter is maybe about 7cm.



During these storms, water was spilling out of the gutter at or near the top of the pipe and running down the wall. It seemed to be overflowing rather than leaking from a hole.



The rooms just below that gutter (in both houses) then developed damp plaster in the corner. I haven't been round next door to look at theirs, but in ours we've got some bubbles in the wallpaper and a few faint bits of mould. Just after the storms there was actually a tiny puddle along the top of the skirting board.



I got in touch with our local go-up-ladders people but they haven't been round yet, but meanwhile I've been trying to work out what's actually gone wrong and what needs to happen to fix it.



Investigations I have made:



Looking at the guttering from above when it was dry. There are no obvious broken bits. (bearing out my impression that the water was overflowing rather than leaking.) It isn't blocked in the open part.



Looking at the bottom of the pipe. I was imagining that there would be a grating there which might be blocked, and hence be blocking the pipe, but in fact the pipe seems to go straight into the ground, so no help there.



Tapping the pipe (about 1m above the ground) to see what sort of noise it made and how much mass it seemed to have, to see if it seemed to be full. I wasn't totally sure, but it seemed to be empty. (Come to think of it, I could probably increase my certainty by doing the same with one I know to be empty, for comparison. It's a plastic one - I wouldn't expect to be able to tell like that with a metal one. The bottom section is metal though, clearly the remains of an older one. The plastic one fits inside the metal one which is probably 3".)



When it rained again the other day, leaning out of the dormer window above the bay window, to see what the gutter was doing. It was working normally. But that rain was somewhat less heavy than the rainstorms in August.



Theories:


  1. There _was_ a blockage in the pipe, but it has gone.


  1. There was never a blockage, and it was just that the rain was so heavy that it exceeded the capacity of the pipe. However, we have had heavier rain blowing towards that side of the house in past years without causing the same problem, so I don't believe this. (But that's why I put in the bit about the roof size and the pipe diameter. Opinions welcome.)

  2. There is a semi-blockage, which slows the flow enough to cause a problem when the rain gets over a certain rate.


  1. Something I haven't thought of.



Questions:


  1. If the guttering problem has cured itself, or when we do cure it, how long is it likely to take the wall to dry, and what should we do to help it? So far I've just been trying to keep the windows open in that room as much as possible when the weather's dry.

(This is the aspect of the problem which I'm mostly worried about - I remember a similar problem where a blocked gutter had been allowed to drench a wall all winter, and it took a very very long time for the wall to dry out, and the skirting board got woodworm. But the drainage at the bottom of that wall was poor, and it had got wet for much longer than this one.)


  1. Is it normal for a vertical pipe taking rainwater from a roof to go straight into the ground? Or if I dig up the garden there am I likely to find a grating obscured by leaf mould?


  1. If there's a blockage in the vertical pipe, and no grating, how do you clear the blockage? (I'm imagining some kind of slightly flexible rods from above, but simultaneously worrying that it means taking the whole thing down)

  2. Where will the underground bit go, and how would we get access to that if necessary? (I'm guessing into the same drainage system as the grid drains in road gutters) And is the bit under the garden likely to be the same diameter as the vertical pipe, or would it be bigger so that any lumpy blockage would flow away if poked along that far? Or is that unpredictable and we'd have to dig up the garden to know?


  1. Are "generic roofing people" likely to be able to sort this out, or do we want someone who specialises in guttering and who'd have particular bits of equipment?

  2. Any other ideas, or useful things for me to know?

Thanks in advance for all expertise and anecdotal evidence :-)


Downpipes don't normally block at the base or in its length, but invariably block at the top in the gutter outlet. It can be a tennis ball or a load of leaves and debris.

It may be that it is blocked just enough to overflow in heavy rain, but lighter rain can get through. Alternatively sheer force of the rain can overwelm any gutter in exceptional circumstances, and there may be no problem.

Under the ground, the downpipe will go into a normal drain and to the public sewer or a near-by soakaway.

Anyone can unblock a gutter outlet - all you need is a ladder, bucket, rubber glove and small narrow trowel.

Be careful though, and use a reputable firm or someone you trust as it is all too easy for someone to con you into more work than is needed as they 'inspect' the roof and you stay on the ground oblivious.

The brickwork will dry out in a matter of days.

Wait until the next heavy rain though to confirm any problem

dg

Also, it is common for the sarking felt which drapes into the gutter at the eaves to rot and so water can seep back into the bedroom.

This is a more involved repair job, but it only affects certain eaves/soffit designs and normally interlocking concrete tiles - not the more traditional 'Rosemary' tiles or slate.

dg

Its probably a blockage in the gutter or top of downpipe.

Rick

Since the storms have you had any overspills from the guttering? If NO then I would put the damage down to storm damage. There were torential down pours in my area in the same month and the rain was flowing over guttering(at the valleys), like a waterfall. This was happening on 4 of the roofs I could see. You could try and contact your home insurance company for advice.

Possibly some lazy git who put the downpipe in position used lengthy screws to hold the sections together or to fix the guttering into its clips. These project into the downpipe and snag anything large that gets washed down, for example a lump of moss. Check to see if there are any screws that go into the downpipe, and if so remove them and rattle the downpipe a bit to see if you can dislodge any blockage ( ensure, of course, that any screws you remove don't leave the downpipe in an unsafe state ).

Andy.

Hello all

Thanks dg, Rick, nthng2snet & Andy for your advice on the guttering problem.

Despite some intermittent airing (perhaps 3 hours of open windows every couple of days?), the wall is still damp (evidence: putting a hand on the inside, it's noticeably colder than the external wall on the other side of the bay window).

Nothing else to report yet due to lack of investigative energy... however I have thought about it a bit and my plan is:

1) Next time we have heavy rain, see if the gutter is still overflowing (provided it's daylight). I haven't been _aware_ of any repeat episodes, but the only heavyish rain has been in the middle of the night and I couldn't be bothered to get out of bed then and go and see. And there hasn't yet been anything as heavy as the August rains at all, I don't think.

2) Someth>Possibly some lazy git who put the downpipe in position used lengthy screws

Incidentally, there is no water standing in the horizontal guttering, but obviously a semi-blockage wouldn't cause that anyway.

More questions...

Regarding the suggestion of contacting the insurance company: I'm wondering if it's worth doing that at this point. My doubt is because none of the damage I'm aware of is anything I'd call anyone in for, so I wasn't thinking of putting in a claim. It just needs the wallpaper bubbles sticking down again and a lick of paint. (Though if the wall is still damp as winter approaches, I may yet spend some time with the radiators on high in that room to help the drying, and that would cost money, but a hard-to-quantify amount.) But maybe I should notify them anyway in case it develops into more of a disaster later? Or can I leave that till "if and when"?

(come to think of it, the insurance side might be complicated by the fact that the overspill was more or less where the guttering of the two houses joins - I'm not even sure who technically/legally owns the downpipe - and I doubt if my neighbour has the same insurer)

Also, given that the wall is still damp after approx 2 months, should I be starting to worry about knock-on effects at this stage? e.g. my nightmare scenario of damp wood favouring woodworm, or anything else I should be looking out for? And any other tips for hurrying up the drying? Would putting the radiators on full actually help or would that be negligible/irrelevant/a waste of energy? & if it would help, is it better to do it with the windows open or closed?

::thinks::

And is the continuing damp conclusive evidence that more water has been added, or is 2 months still within a likely time for a rather wet wall to dry? (I'm a bit worried by the comparison with dg's prediction of "a matter of days", given I haven't seen any more overspilling to "blame it" on.) Is it one of those situations like a dry sponge vs a wet sponge, where the brickwork being already wet through could make it soak up the "ordinary" rain more than it would otherwise do?

Further thoughts welcome...

cheers

I wouldn't get the insurance people involved for this, it's not a big enough deal. You can inform them if and when you have been unable to stop the problem yourself. You will have to determine whether there is still water splashing against the wall. Next time it rains really hard ( next few days might do ) inspect the guttering, if it's dark shine a torch on it to see if it's still overflowing.

It isn't easy to tell how long your walls should take to dry out. My brother had a problem with 18" solid walls. Rain got in via cracked cement render, which could not escape again to the outside since cement render is impervious, so it hung around in the wall gradually oozing out of the plaster inside. He had to strip off lots of wallpaper and run a dehumidifier for 6 months to dry it out.

If you have a cavity wall, that should not take nearly so long to dry out, but I imagine it would still take weeks. Yes, warm radiators will help, it raises the vapour pressure of water and causes it to evaporate more quickly. Yes, ventilation will help too, since water cannot evaporate if the air is too humid.

I don't think you need worry overly about woodworm or rot, but you *do* need to figure out exactly what is causing the problem, else it's all speculation, things will drag on.

cheers,

Andy

Andy writes

Indeed, you are right Andy, and that is just what I was thinking when I woke up at 5am and it was raining! so I have now managed to answer some of my own questions and I have a couple of different ones...

In that not quite so heavy rain, water wasn't coming over the edge of the horizontal guttering, but looking from below I could see it was still dripping from the cuboid boxy bit which catches the angled bits from both sides, I think over the edge of it. :-(

(feeling a bit foolish now, because I probably could have seen something like that last time I had the torch out, if I'd looked from below, but I realise in retrospect I was assuming that the problem would look the same the second time around)

I forgot to say in my previous post that aforementioned go-up-ladders people have been failing to get back to me about either a date to do the job or their arithmetically mistaken written-down estimate. (it didn't add up internally. I had asked for it written down not just as usual good practice but also so that I could show it to my neighbour.) I've left them two messages and now I'm thinking they obviously don't really want the work and I need to find someone else instead.

Incidentally, it also occurs to me that a ladder would not be required if someone were prepared to climb out of the dormer window and lie across the top of the bay to do the job. I recall seeing someone "catching the sun" there at one of the adjacent houses with a book one summer, and it wouldn't be hard to get out there. (In my more reckless days I would have done it myself but now I am more aware of the risks, and indeed of the value of my life :-) )

so my new questions:

Somebody was telling me recently about new legislation about going up ladders above a certain number of storeys. Would it apply in this case? It's one of those houses where there are steps up to a tiny garden and then steps to the front door, so the gutter in question is perhaps about two and a half storeys up from the street (but less if you stood the ladder in the garden, which is probably possible at this point of the frontage).

Second question: assuming I do get someone in from a guttering maintenance company, and assuming all it is is rubbish caught in/near the top of the pipe, roughly how much should I be expecting to pay?

Thanks

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