# Forum Home Renovation Roofing  Roof infill strips recommendation to prevent water ingress

## DaleBlack

Hi i have a small roof built over a 6m by 1.5m long storage zone, a recent addition to my garage. 
in certain rains water is leaking through, when i tested the gutters with the carpenter who built it using two hoses on full, it drains fine. But there is obviously some conditions that are bringing the water inside. 
So we have thought to put those infill strips in. 
I was thinking of this brand  https://roofinfillstrip.com.au/index...&product_id=55   

> "
> Infill strip may not seem important but when they fail the costs associated can be very significant.. 
>   There are a number of materials used to manufacture this product,  some use an open cell foam and then fill it with bitumen which we would  not recommend as the bitumen is not stable in hot situations & can  leach out and or stain. 
>   Closed cell foam PE foam that  is  imported from overseas has a  potential problem in terms of longevity because you can have no idea how  much filler is used in the foam manufacture which makes it more  vulnerable to degradation, shrinkage & pest attack. 
>   Buy Australian made & you can be assured of the quality and adherance to published standards."

  vs  https://www.bunnings.com.au/ormonoid...ofile_p1063471   

> A pre-formed, flexible, polyurethane foam-sealing strip impregnated with  bitumen. Ormonoid Compriband can be compressed to seal expansion and  construction joints and can also be used in gasket seals.

  
what do you think?

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## SilentButDeadly

If your carpenter built the roof with less than 5 degrees fall and then covered it with corrugated iron...then your solution is on your carpenter. Neither product will save you.

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## FrodoOne

Your post raises a few questions.
"In certain rains water is leaking through" 
 Through where, between the corrugated sheets or 
at the high end, where the roof meets the existing building? 
If between the sheets, do those sheets have sufficient overlap - and does it have sufficient "fall", as *SilentButDeadly* mentioned?
If where the new roof meets the existing building, what overhangs the sheets concerned?  The reason I ask these questions is that we have a pergola, roofed with Corrugated Polycarbonate Roofing Sheet laid on bearers up to the original building and underneath the buildings original guttering on the high side. (An additional gutter and down-pipe was installed on the low side of this sheeting.) 
At times it was noticed that, in one small area, after some rains water was seen to have run down the house wall from "under" the original guttering (probably wind driven.)
 A few "lengths" of a product such as https://www.bunnings.com.au/suntuf-b...-pack_p1010499 between the sheeting and the original guttering at this point seems to have fixed this problem. 
I note that https://www.bunnings.com.au/ormonoid...iband_p1060534 seems to be a 2 metre pack of the 10 metre product to which you referred. 
If your problem is akin to the one that I described, you would need only one of these (or 3 of them), depending on whether the 1500 mm or 6000 mm side of the roof abuts the garage.

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## Marc

Sometimes it is as simple as bending the edge of the sheet at the high side. Yes it should be the norm but as I discovered a few times myself ... it is not.
Of course if it is plastic, bending the edge will prove difficult. Not impossible though.  :Smilie:  
A flat roof requires the sheeting that is designed for ... flat roofs. Building a flat roof with corrugated sheeting is asking for trouble. The edge that is over the gutter can be bent down in a flat roof sheet to stop superficial tension making water run up under the sheet at the edge. Corrugated iron does not like that, it will tear and rust if you do so.  
A picture of the problem roof would help.  
I can also contribute with a bunnings link https://www.bunnings.com.au/200mm-co...liers_p6010577 
However ... as noted by Silent ... if it is too flat, and made with corrugated iron, it will leak at both ends no matter what.

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## cyclic

> Hi i have a small roof built over a 6m by 1.5m long storage zone, a recent addition to my garage. 
> in certain rains water is leaking through, when i tested the gutters with the carpenter who built it using two hoses on full, it drains fine. But there is obviously some conditions that are bringing the water inside. 
> So we have thought to put those infill strips in. 
> I was thinking of this brand  https://roofinfillstrip.com.au/index...&product_id=55   
> vs  https://www.bunnings.com.au/ormonoid...ofile_p1063471    
> what do you think?

  You need to tells us what profile of roof you have, and of course a pic or 3 of the area leaking will get you a definite answer. 
FWIW I have pulled enough of that stuff out to know it is overpriced and not worth the trouble.

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## DaleBlack

> You need to tells us what profile of roof you have, and of course a pic or 3 of the area leaking will get you a definite answer. 
> FWIW I have pulled enough of that stuff out to know it is overpriced and not worth the trouble.

  Hi all, we believe the leak is not at the sheet-wall junction but the sheet - gutter junction, i had seen comments on this foam stuff that over time, say 4 years later it will be brittle and fall out?  does bitumen impregnated help there?
does the bitumen product leak out in Summer? 
I will get some pictures

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## DaleBlack

Above is the approx 1.4M wide (sheet width not gutter) by 6m long skillion roof off the edge of a garage. The above view faces to the back of the property and the far end in the image is the high point.

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## DaleBlack

I only put in two measurements 
would this be the pitch?  https://www.omnicalculator.com/const...the-roof-pitch     https://www.ausstyleroofing.com.au/f...-should-i-use/  
Should the profile be this for pitch 2degrees or less   
or maybe the trimdeck 
for between 2 - 5 degrees? 
but outside of changing the roof, maybe what Marc said   

> the edge that is over the gutter can be bent down in a flat roof sheet to  stop superficial tension making water run up under the sheet at the  edge. Corrugated iron does not like that, it will tear and rust if you  do so.

  though i note your comment re rust, wouldnt the foam , compressed enough stop that water running up the sheet at the gutter end?  outside of it collasping 4 years later?  https://www.mycladders.com.au/5-ways...-roof-leaking/   

> *5 control measures to stop a flat roof leaking*   Install roofing material to the  manufacturers recommendations. This may seem straight forward, but its  something we see time and time again on DIY projects and extensions.  Most manufacturers will recommend turning up the top of the sheets and  turning down the bottom, which must be completed using a turn up and  turn down tool.Extend roof sheets further into the  gutter. The more overhang you can achieve into a gutter, the less chance  you have in capillary action of water creeping back up the roof sheet  and entering the roof. The minimum standard is 50mm. On a flat roof, we  suggest starting at 100mm of overhang. If you can, aim for 150mm. Just  make sure you leave enough room for gutter maintenance.Install a gutter flashing between the  gutter and the roof sheeting. This flashing rests on the front edge of  the lowest batten with a squash fold to direct any possible water flow  sideways instead of back into the roof. This flashing is also a must  when installing profile filler at the gutter edge.Profile fillers at the tops and bottoms  of sheets. At the gutter edge of the roof, install a pre-formed foam  filler between the roof sheet and the gutter flashing. This will act as a  physical water barrier. Install a profile filler at the highest points  under a ridge cap or apron flashing to stop water ingress into the  building.Under seal all flashings with a  substantial amount of quality silicone. Rivet the joints of the  flashings at 40mm increments and fill the rivets with silicone

  I note the 3rd dot point about the gutter flashing, can these be made to work in my case? with a corrugated shape?  does anyone have some clear images or designs of this? 
Thanks

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## cyclic

125mm rise over 1400 is close enough to 5 degrees fall, however,
in 
Pic 1 Left in pic the roof is rising at the gutter line thus changing the 5 degree pitch to less and allowing the water to track back under roof sheet
Pic 2 shows water laying in valleys of corrugations
Pic 3 is ditto + left top corner is very sus
Pic 4 Roof sheets appear to not be at least 50 into gutter
Pic 5 Water may be getting under flashing especially if the sheets under flashing are not weathered (valleys turned up) and why is all that silicone against the wall, did you not slip the flashing up behind the wall sheet ?? That silicone can easily cause leaks.  In Qld the flashing would have a turn down at 45 degrees 30mm and this would be scribed into the roof profile.
Pic 6 shows water in sheet valleys which will track back under roof 
Best way to stop the tracking back is a flashing across the batten 50mm, then down at 45 degrees 50mm, then drop into gutter 20mm

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## DaleBlack

> 125mm rise over 1400 is close enough to 5 degrees fall, however,
> in 
> Pic 1 Left in pic the roof is rising at the gutter line thus changing the 5 degree pitch to less and allowing the water to track back under roof sheet
> Pic 2 shows water laying in valleys of corrugations
> Pic 3 is ditto + left top corner is very sus
> Pic 4 Roof sheets appear to not be at least 50 into gutter
> Pic 5 Water may be getting under flashing especially if the sheets under flashing are not weathered (valleys turned up) and why is all that silicone against the wall, did you not slip the flashing up behind the wall sheet ?? That silicone can easily cause leaks.  In Qld the flashing would have a turn down at 45 degrees 30mm and this would be scribed into the roof profile.
> Pic 6 shows water in sheet valleys which will track back under roof 
> Best way to stop the tracking back is a flashing across the batten 50mm, then down at 45 degrees 50mm, then drop into gutter 20mm

  Is the flashing sort of like the below but the last bit goes down vertical 20mm instead of curling back   
Installed will look like this, except the below has section B vertical not your 45   
This one below also drops vertically in its second stage so i suppose its not a suitable design.   
I was also told to help water get away by weathering the front lip of the roof sheet  down with a pair of plyers. This could encourage water to drip rather  than capillery back under. Essentially the reverse of this process that  should be applied at the top of the roof sheet. But this idea seems to me to be a cheaper way avoiding pulling up the sheets and putting in the flashing whilst possibly also rusting according to Marc above.

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## cyclic

Flashing 20 as you describe, Yes, but it does not have to be 45 degrees, it is just my preference. 
Turning up of the sheets should have already been done before flashing. 
Turning down custom orb (corrugated) is as Mark described, difficult not to tear the sheet, however, even if the valleys are turned down and split, the water will drop off into the gutter except for where the sheets lap/join. 
At the laps, it usually tracks back under no matter what. 
This same problem can also apply to trimdeck, so a flashing into the gutter is necessary, especially as I noted your roof is actually screwed to the point of the roof sheeting being no longer 5 degrees in some places at the gutter.

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## DaleBlack

Cyclic thanks, your flashing is 50mm back from the edge, is that enough is it to stop trackback? ie it only goes about 50mm up a 5degree pitch roof before falling straight down into the roofspace?

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## cyclic

> Cyclic thanks, your flashing is 50mm back from the edge, is that enough is it to stop trackback? ie it only goes about 50mm up a 5degree pitch roof before falling straight down into the roofspace?

  Yes, the idea is, the roof will be sitting on the flashing, so as the water tracks back it will get to the flashing and run down the flashing.

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## DaleBlack

> Yes, the idea is, the roof will be sitting on the flashing, so as the water tracks back it will get to the flashing and run down the flashing.

  Oh, i thought that gravity itself starts to cause it to drop off the underside of the roof at a certain point as the sheet rises up and up, ie the tracking back is limited even if the flashing never touches. 
because the profile is corrugated, how does the flashing ever properly meet?wont the flashing only touch the valleys and not the rises? or I suppose its tracking back only on the valleys :> so it does meet.

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## cyclic

> because the profile is corrugated, how does the flashing ever properly meet?wont the flashing only touch the valleys and not the rises? or I suppose its tracking back only on the valleys :> so it does meet.

  You got it.

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## DaleBlack

Hi Cyclic 
I probably didnt explain it properly but the carpenter mentioned 
"
I cant see that extra flashing helping a great deal in our case  because it doesn't actually fill the gaps, unless it was pushed further  than the ends of the sheets (ill send a picture (B))."    
He mentioned, though i am waiting to confirm, possibly using something like the below cut to the corrugation, siliconed in

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## cyclic

Enough silicone will fix any leak.

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## droog

> Enough silicone will fix any leak.

  Yep, there are even plumbers that believe flashing comes in a tube.

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## peejay

There are only three things in life that are certain...... death, taxes,  and silicone !

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## METRIX

> Hi i have a small roof built over a 6m by 1.5m long storage zone, a recent addition to my garage. 
> in certain rains water is leaking through, when i tested the gutters with the carpenter who built it using two hoses on full, it drains fine. But there is obviously some conditions that are bringing the water inside. 
> So we have thought to put those infill strips in. 
> I was thinking of this brand  https://roofinfillstrip.com.au/index...&product_id=55   
> vs  https://www.bunnings.com.au/ormonoid...ofile_p1063471    
> what do you think?

  Yep, they do work, and make sure the sheets are bent up at the high end under the flashing, what type of roofing is it and what is the pitch ?

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## METRIX

> Yep, there are even plumbers that believe flashing comes in a tube.

  Or ruin everything, I have see many terrible silicon jobs by plumbers, you would think for someone who uses the stuff to fill everything they would at least know how to apply it neatly.

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