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Flat roof: drip : you know the story.


ToughButterCup

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I'll spare you the details.

I'm trying to trace a tiny weeny driplet that is squeezing itself through our brand new flat roof. Yes, it's the installers responsibility. Yes, tell him to sort it. Yes.

 

But I want to find this sodding leak point. I have traced it to one general area. By running a hose over it when the roof is dry. 

Now I need to identify the actual place that leaks.

 

Is there any way of colouring water such that the colour will still show once it trickles through the roof?

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Yes . You can buy dyes . My favourite is the blood red one . I used far less water and it was bright - looked like a massacre- so good “visibility “ .

Haven’t tried the luminous green one yet !

From eBay I recall 

 

water trace dye

Edited by pocster
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33 minutes ago, nod said:

Not being funny Ian et the installer spend time with food dies etc 

 

Perish the thought  Gary.

Yes, of course I will. But I want to know the answer to the question before I ask it. If it takes 10 minutes to pop up on the roof and drop some dyed water and watch where the drip comes through then I'm gonna do that.  I'm done with letting trades do their stuff without me taking an active interest in what they do..... ?

1 hour ago, pocster said:

[...] .

Haven’t tried the luminous green one yet !

[...]

water trace dye

 

??  Top banana.

I'll have a good with free then: so we can swop drip stories in the pub .

19 minutes ago, Ian said:

[...]

Not sure what type of roof you have?)

 

Evalon. 

 

Off to the gym to pump iron  - takes courage does that exercising next to really super fit female stick insects  . Ahhhhh poor me eh?

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whats the roof make-up?  what stage of construction is it at where the leak is manifesting...ie are you seeing a wet underside of roof deck or are you seeing wet ceiling plaster??

 

Where water is coming-out is one thing, where its going in is another....as I'm sure you appreciate.

19 hours ago, Ian said:

some types of flat roof (eg Sarnafil) can be tested electronically for leaks with good accuracy. (Not sure what type of roof you have?)

Apparently the accuracy is not really so good as to provide any truly comprehensive reassurance but it will serve to pick up some installation errors.

 

On tuesday my sarnafil installers will attempt to identify the source of my second leak and i'm bracing myself for the need to possibly remove half of the green roof growing medium (approx 6 tons) and put it 'somewhere'!

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Looks like evalon uses heat welded joints like sarnafil.  I had a 4" length of weld that....wasn't welded. Sloppy installation, although easy to understand how it could happen....it's unskilled mind numbing work, but does require absolute fastidiousness, so if the phone goes while your at it and its the wife wanting a divorce it's easy to see how a fitter might falter.  Check you cant push something like a very blunt bradawl under any part of the welds.

I assume its membrane, insulation, vcl, deck....so if water has got through the membrane it will drop to the vcl, but thats near as dammit waterproof so the water will then run along the fall until it finds a failing in the vcl through which to soak the deck.....probably in a totally different area to the membrane fail.

If your leak is at the extreme low edge of the fall; I believe my current leak will prove to be where the vcl turns up the side of the stop-edge that borders the roof edge which is the low side of the fall...I remember the vcl was installed with varying degrees of radius here rather than being tucked hard against the 90 degree turn, so there would be unsupported bits of vcl with pockets of air in effect, which I think could viably be punctured by the square edged insulation when laid.  If the puncture wasn't entirely at deck level but say 6mm up then my vcl could be holding substantial water built up over time and only now overflowing each time it rains.  None of which informs where the actual membrane leak is.

 

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This might not be helpful but might depending on where the drip appears. I stupidly cut a wee bit of flashing to put at a downpipe outlet and sliced through and put a score in the EPDM (yes, don't even ask, I was nearly done and rather than...you know how it is). 

 

Anyway, I knew exactly where I'd sliced (about 3cm) and boy was it hard to find it again only 5mins later when I had the patch sorted! My point is only - once you've eliminated the other suggestions above, if it's simply a puncture no-one 'fessed up to, it can be hard to find - but easy to fix. You may need to identify a broad section and on hands and knees, work it methodically to try find it.

 

Our EPDM has insulation directly below and then a VCL below that - which means if we ever did have a leak it wouldn't come through - not sure if you're is the same - I don't recall the build up? Point being - wherever the water is entering water could be redirected for the whole length of the pitch assuming a slight fall)?

 

Good luck!

 

 

Edited by jamiehamy
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49 minutes ago, jamiehamy said:

This might not be helpful but might depending on where the drip appears. I stupidly cut a wee bit of flashing to put at a downpipe outlet and sliced through and put a score in the EPDM (yes, don't even ask, I was nearly done and rather than...you know how it is). 

 

Anyway, I knew exactly where I'd sliced (about 3cm) and boy was it hard to find it again only 5mins later when I had the patch sorted! My point is only - once you've eliminated the other suggestions above, if it's simply a puncture no-one 'fessed up to, it can be hard to find - but easy to fix. You may need to identify a broad section and on hands and knees, work it methodically to try find it.

 

Our EPDM has insulation directly below and then a VCL below that - which means if we ever did have a leak it wouldn't come through - not sure if you're is the same - I don't recall the build up? Point being - wherever the water is entering water could be redirected for the whole length of the pitch assuming a slight fall)?

 

Good luck!

 

 

all the reasons given here is why i would not use a rubber roof .

GRP does not puncture .

just cannot see the attraction of a roof that can puncture 

local hotel had one and the crows would swoop down and pinch left over food from the tables  outside --then fly up to roof and then eat it involving lots of pecking .

-you guessed it --

they pecked   holes in the roof

 it was replaced with a grp one --problem solved

 

Edited by scottishjohn
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19 minutes ago, scottishjohn said:

all the reasons given here is why i would not use a rubber roof .

 

 

Why I would not use a flat roof.

 

Of course there are variations on "flat"  I would accept a low pitched sloping "flat" roof.  One of the most stupid ideas I saw was a Grand Designs that had a totally flat roof that was designed to permanently hold a few inches of water (aparently that was the UV protection) and yet you have guessed it, it leaked.

 

There is a good reason most roofs slope, so the water runs off quickly.  Of course a sloping roof can leak, but not as often as a "flat" one does.

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9 minutes ago, ProDave said:

Why I would not use a flat roof.

 

Of course there are variations on "flat"  I would accept a low pitched sloping "flat" roof.  One of the most stupid ideas I saw was a Grand Designs that had a totally flat roof that was designed to permanently hold a few inches of water (aparently that was the UV protection) and yet you have guessed it, it leaked.

 

There is a good reason most roofs slope, so the water runs off quickly.  Of course a sloping roof can leak, but not as often as a "flat" one does.

that was common 40 years ago and you had a layer of chips on it to act as something to stop the water evaporating quickly to stop felt overheating  -usually

-meant to hold up to an inch of water  before it drained off 

my petrol station is like that --and after 20 years it had grown a self seeded roof garden -just had to weed the big things out  now and then  and now its nearly all sedum --never leaked 

Edited by scottishjohn
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One of our BTL's had a flat roof like that over the "out house"  It was on it's last legs and had seen a repair or 2, but thankfully it lasted until we sold the place.  It is still there so presumably holding up still and still not leaking, but most have been replaced with a mono pitched tiled roof now.

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49 minutes ago, scottishjohn said:

all the reasons given here is why i would not use a rubber roof .

GRP does not puncture .

just cannot see the attraction of a roof that can puncture 

local hotel had one and the crows would swoop down and pinch left over food from the tables  outside --then fly up to roof and then eat it involving lots of pecking .

-you guessed it --

they pecked   holes in the roof

 it was replaced with a grp one --problem solved

 

Wouldn't disagree with that - but life is not that simple is it?! The chances of getting the right conditions for EPDM in the west of Scotland are far higher than GRP for starters, also the labour required for EPDM is far less. I know for a fact is we had gone for GRP we would have not had the covering on for a further few months at least (we did the EPDM in Autumn - two bone dry days and zero experience before hand). Not a chance in heck we'd have done the GRP for 270m2 in that window with zero experience! Swings and roundabouts!

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50 minutes ago, ProDave said:

One of the most stupid ideas I saw was a Grand Designs that had a totally flat roof that was designed to permanently hold a few inches of water (aparently that was the UV protection) and yet you have guessed it, it leaked.

 

Wasn't that the couple where he was German and they had a German system and their installers come over to fit it?

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1 minute ago, Onoff said:

 

Wasn't that the couple where he was German and they had a German system and their installers come over to fit it?

I don't recall the details other than it was totally flat with an upstand around it, and was designed to permanently hold water.  It just struck me as bonkers.

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28 minutes ago, ProDave said:

I don't recall the details other than it was totally flat with an upstand around it, and was designed to permanently hold water.  It just struck me as bonkers.

 

I remember nearly 40 years ago being prompted to "just jump down" onto a lower roof whilst doing a survey as a 16 year apprentice. The bloke with me knew they were doing a flood test on the roof, I didn't and it was as still as a mill pond.....

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On 19/10/2019 at 16:28, AnonymousBosch said:

 

Perish the thought  Gary.

Yes, of course I will. But I want to know the answer to the question before I ask it. If it takes 10 minutes to pop up on the roof and drop some dyed water and watch where the drip comes through then I'm gonna do that.  I'm done with letting trades do their stuff without me taking an active interest in what they do..... ?

 

??  Top banana.

I'll have a good with free then: so we can swop drip stories in the pub .

 

Evalon. 

 

Off to the gym to pump iron  - takes courage does that exercising next to really super fit female stick insects  . Ahhhhh poor me eh?

 

Get a sugar daddy tee shirt.

 

Or remember STs ‘pony having a poo’ comment.

Edited by Ferdinand
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8 hours ago, ProDave said:

Why I would not use a flat roof.

[...]

There is a good reason most roofs slope, so the water runs off quickly.  Of course a sloping roof can leak, but not as often as a "flat" one does.

 

Our flat roof slopes 160 mm over 9 meters.  No water stays on it for long.

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