Roof infill strips recommendation to prevent water ingress

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.

Originally Posted by 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



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.

Originally Posted by cyclic

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

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.

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

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

Originally Posted by 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

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.

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.

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?

Originally Posted by 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?

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.

Originally Posted by cyclic

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.

Originally Posted by DaleBlack

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.

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

Enough silicone will fix any leak.

Enough silicone will fix any leak.

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

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