I wonder... Gutter discharging onto roof tiles

I'm probably being over cautious (it's what I do best!)

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(video of water discharging from 10m2 flat roof onto double-pantile tiles)

If you look at 0:04, 4th tile from top (inc half tile at top) and

0:08, 1/3 up the video from bottom you will see a nice little bow wave of water lapping up to the tile joint to the left.

Now, it would have to get past 2 more small ridges to leak, but today's rain whilst moderately hard was not torrential.

The other half of the dormer roof has the same arrangement but the water hits the other half of the tile profile so any bow wave would wash clean over the joint top rather than into it.

No evidence of leaks inside, or damp membrane.

Just wondering if I should maybe put an corner onto the end of that gutter to send the water stream left by half a tile. Or not bother...

How tolerant are interlocking tiles of this sort of abuse?

Reply to
Tim Watts
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On Saturday 24 August 2013 16:27 Tim Watts wrote in uk.d-i-y:

Another couple of videos:

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and a close up

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Reply to
Tim Watts

In message , Tim Watts writes

You could put a *stop/end/outlet* and a bit of down pipe to give full control.

We once had leak problems in a chalet bungalow with retro-fit dormers (unguttered). I think rainwater drips were able to find their way under a single tile lap lead apron under some wind conditions.

Time will tell:-)

Reply to
Tim Lamb

On Saturday 24 August 2013 19:21 Tim Lamb wrote in uk.d-i-y:

I think that might be wise in the long term.

I need to go up there (= buy a long enough ladder) to replace the TV aerial at some point. I'll do it then. It's hose testable.

Reply to
Tim Watts

I did this just recently. I didn't use a stop-end, just an outlet. At the bottom of the short downpipe, I cut the pipe off at an angle

90 degrees to the roof surface, very specifically so there was next to no chance of any debris getting stuck at the bottom of the downpipe, which could start a backlog of blockage (seen this very often at the bottom of such downpipes, and this one is pretty inaccessible after the scafolding was taken down). Don't fit a shoe spout either, for the same reason.

Test it with a hosepipe running hard into the gutter, some way back from the low end.

The other thing I would check is what happens at the bottom of the stream coming down the tiles. Sometimes you need extra protection to stop it flooding across the top of the gutter, and/or over the inside edge onto/behind the facia. I caught a fraction of a second glimpse of what looked like an internal gutter at the bottom with a facing glass panel roof. I don't know if/how the glass is sealed to the gutter edge, but again, there may be the possibility of spill-over at this point. Another good reason to test with a hosepipe into the top gutter.

I doubt you'll have any problems with the flow down the tiles.

Reply to
Andrew Gabriel

As others have said stop end outlet and short bit of down spout. Think I'd put a shoe on it so the out flow is directed down the tiles. I've never known a shoe block up unless the grass as grown and built up a lot in front of it. B-)

Looking at the vid that shows the water falling from the gutter I'd be more concerned that the flashing doesn't appear to go under the tiles but is butted against the curved tile edge. Water will get in that gap... I guess if the sarking runs under the tiles and flashing and up the wall a bit in one piece it doesn't matter all that much but it don't look right. B-)

I'd expect the flashing to go under the tile and have an upstand underneath the curved bit, interlocking a bit like the tiles do. Might need to be dressed over a lath running down the roof along that line but not sure if that would work with such thick tiles overlapping each other. I'm used to slate...

Reply to
Dave Liquorice

On Saturday 24 August 2013 21:13 Andrew Gabriel wrote in uk.d-i-y:

Thanks - that sounds like a good idea cutting the pipe outlet at 90 degrees to the roof.

Yes - it hits into a quite deep box gutter for a (new) conservatory. That seems fine, except for the noise of the water hitting.

I mind that less as any leaks would be immediately apparant. When I finish th edormer work inside, leaks from the tiles will not be visible until it's too late.

Many problems would be solved by discharging the gutter the other side (hits the right half of the pantile profile, misses the conservatory) - the big fly in the ointment is the flow would come out onto a short flat lead roof section (1m deep, 4m wide) *right on top* of a lead roll joint which is possibly why the roofers avoided doing this in the first place.

The original gutter for the dormer had a short central downpipe down the front dormer wall screwed into the tile - but they were very much against screwing anything into the tiles after changing them.

Reply to
Tim Watts

On Saturday 24 August 2013 22:44 Dave Liquorice wrote in uk.d-i-y:

Agreed :)

That's actually a full tile there - the lead dresses over the high edge down into the valley, and up untder the side tiles.

They went to some trouble getting the tile layout optimal - as it happened, all of the tiles up the side of both dormers are whole and uncut.

Yeah - you get a different dressing with interlocking pantile style - and the odd subtle problem like concentrated water flows like this one (normal tiles it would of course spread out).

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Reply to
Tim Watts

A shoe would look nicer. B-)

If that's the noise on the vid looking up it would drive me potty.

12 to 18" bit of gutter up under where the flow from the dormer roof comes down and pointing in the direction of flow in the box gutter? Might need to have the bottom end supported a bit (1/2"?) above the box gutter so it doesn't trap debris.

Bit of dreessed lead under the relevant tile to direct the flow onto the flat lead roof or into a bit of gutter laid mostly across the roof to its gutter. Don't want to take it to the edge as the chances are the flow will be moving quite quick and overshoot...

Reply to
Dave Liquorice

OK, didn't really think you'd have let your builders get away with such a thing. Not familiar withe the techniques that fancy curved tiles require. B-)

Reply to
Dave Liquorice

On Sunday 25 August 2013 15:53 Dave Liquorice wrote in uk.d-i-y:

SWMBO said the same.

It is a very difficult problem - as mentioned earlier, it was the only easy place it could discharge - unless they make glue-on gutter clips so I could fit a central downpipe and miss the conservatory. No way am I going to drill the vertical tiles - if you break one, you'd have to strip that section right to the top to replace it (roofers said so) on account of things being mortared together.

Impossible to fit now - but it's given me an idea: I reckon I could do something similar with a bit of lead bent into a saddle and just sat in the bottom of the box gutter so the flow hits the lead and gets pushed sideways in the direction of flow. The lead would be like a ski ramp sat up on 4 legs

Water hitting lead doesn;t make much noise...

Reply to
Tim Watts

gutter?

Think my explantion might be a bit off. Length of gutter in the box gutter to catch just the flow from the dorma roof as it leaves the tiles and redirect it the correct way down the box gutter.

Yeah might work, have the lead up close to the bottom tile so it more just flows onto it and is redirected rather than have it fall very far. A bent U shaped channel, wide at the tile end narrows towards the bottom where it allows the flow into the box gutter. If the water falls far onto the lead it is likely to transmit the thumps to the plastic (? it sounded like it) box gutter.

Reply to
Dave Liquorice

Any possibility you could get a brown coloured down pipe tucked in as best you can to the "gully" part to the right as viewed from the bottom to carry that flow?..

Reply to
tony sayer

On Monday 26 August 2013 15:57 tony sayer wrote in uk.d-i-y:

You mean in the gulley region between the hipped roof and the dormer vertical side wall?

Not a bad idea! Given most of the weight would be taken by sitting in the groove - there would be a slight tendecy to slip down but it would be easy to wedge it at the bottom and have a 90 degree bend shooting the water the right way.

Reply to
Tim Watts

In article , Tim Watts scribeth thus

Yes something in that area along those lines. Can you get transparent down pipes I wonder?, or some that won't discolour. I've got a similar problem coming up for "sorting" like that 'ere long;!...

Reply to
tony sayer

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