super wide tray flashings for low pitched metal roofs. Deserves a fresh look.

Ajouté : 2026-05-07

[00:00:00]Now recently I was flying a drone over some roofs to do some roof inspections and I came upon a new development. Now this is a flat roof and I love talking about flat roofs in modern houses. And as I flew the drone over this particular development and looked at this roof and how they lay the roof out, I found something really interesting because you know how I don't like box gutters on flat roofs and I always insist on the roofs draining to ease gutters and not box gutters. Now, I happened to see that on this particular roof, even though they had box cutters, there was this section of roof where they totally eliminated a length of box cut gutter.

[00:00:45]And I went, well, that's interesting how they've managed to do that. So, how do you totally eliminate a box cutter from a flat roof? Now, that's an interesting question. And what I saw on this particular roof was that it seems like that the designer had designed out the box cutter. And as a result, the roofer had to come up with a solution to roof this particular area that didn't have a box cutter. What it looked like was that this whole section of roof was covered by a flat flashing. However, we call it a super super wide tray flashing because that's how you eliminate a box scatter.

[00:01:23]Put in a tray flashing. in this case super wide one. And this got me thinking a little bit because we come across the need for super wide tray flashings because when the penetrations get big then the tray flashings get proportionally a lot wider. And we've come up with a means of designing and installing these super wide tray flashings. And to look at how we do this in detail, we've got a training video here that looks at how we design and approach installing tray flashings. Now, we're going to be looking at tray flashings in here and specifically the super wide tray flashings. Now, we use tray fleshings a lot. We would use tray flashings to go around duct tights and we would use tray flashings where there's a problem with the joints in the sheets. So there's many areas where we use tray flashings. And the standard narrow tray flashings are very simple to do and they're not usually problematic.

[00:02:27]Now where tray flashings become a little bit of a problem is when they become super wide. For instance, this roof here with this big skylights, you got to use very wide tray flashings for the skylights. And as a result, these tray flashings have a little bit of a challenge to them. And the challenge is to do with the materials because the coils that are used to make up fleshings for us, they are limited in their width.

[00:02:55]Now coils come in all different widths, colorbond coils, sync coils, but the maximum width of a coil supplied by blue scope is 1,200 mm. So because of this limitation on a 12 mm wide coil, when you have a tray flashing that's wider than 1200 mm, you can't have a single width tray flashing. It's got to be done in multiple widths. And the way that is done on this particular roof, the skylights, is that the fleshings has been put crosswise. And as you can see here, the skylight is wider than 1200.

[00:03:40]So, as a result, the fleshings can't be done in a single length because it's wider than 1200. So what this particular roofer has done is that he has used the 1,200 mm wide tray flashings crosswise.

[00:03:58]So it's going across the roof. So as we can see here, the tray flashings are roughly about 1,200 mm wide going across the roof. And this results in multiple silicon lap joints. And the problem with lots of lap joints is that you got to get all the laps 100% perfect because if you get any leaks on the laps, then you could get a leak going in under the tray flashing and then you have a skylight leak in this particular instance. So this is a super wide tray flashing done with the flashings installed crosswise to the roof. So, what if we install the fleshings lengthwise in the same line as the roof sheeting? So, on this particular job, this is what happens.

[00:04:50]You've got a super wide tray flashing and it's installed lengthwise in the same direction as the roof sheeting.

[00:04:59]Same thing, you're limited to the 1200 wide sheets and they go up and down the roof. So you've got less joints as you go down the roof because you can install the tray flashings 1 1200 mm wide in the lengths that you can transport. So it's in whatever length you can transport and so you get a joint a lap joint as you work down the roof. But you also got a very very long lap joint up and down the roof. As you can see in this particular instance, there's a very very long lap joint that if it's not done 100% then they will leak and then you got a problem. Now is an aside which has got nothing to do with the water leakage.

[00:05:47]Some of you may ask what are those diagonal stiffness put on top of the tray flashing? Well, it does a couple of things. I think it stiffens the tray flashing up so that you don't get the tray flashing bouncing up and down on the roof as the wind blows. So, it stiffens the tray flashing up, the super wide tray flashing. But it also does another thing because on this particular roof, we wanted to divert the water off to one side of the roof. So, it went into the box gutter on the right hand side. So what these stiffeners do is that they divert the water on the diagonal down onto one side of the tray flashing and down the roof so that it can go into the box cut scatter. So we haven't got a water that is not flowing down the super wide tray flashing without any guidance. So it's guided down the tray flashing and that's what the stiffness are for. So the stiffness are a good idea. So, if we combine the stiffness with a super wide tray flashing, what do we get?

[00:06:58]So, back to this roof with the skylights. Is there a better solution for the super wide tray flashings? So, what we've done is we've come up with a solution that we are using now. So when you guys come up with this type of tray flashing, you'll know why we've developed this solution and how it's actually used. So what we've done is we've actually stolen from Lysart because Lysart's got their Zenith roofing which is meant to be a wall cladding and also a can be used on the roof. This particular Imperial is 525 wide. It's not as wide as we want to, but basically the design of the Imperial 525, this basic profile is what we've stolen of Lysart. So what we're doing is that our super wide tray flashing is a combination of this particular design.

[00:08:06]So we come up with six standard flashings that when we combine them gives us the flexibility to install a super wide tray flashings of any width and any length. So when you see these flashings on your job sheet, you'll know how they go together. Now, if we look at if you wanted a super wide tray flashings, you could put the three combinations together and it can make up almost a 3 m wide tray flashing. So, this combination would give you a a tray flashing about 3 m wide. Of course, if you want to go any wider, you can double up one of the inner trays to just increase the width of your super wide tray flashing. So, this particular combination allows you to go and run the super wide tray flashings up and down the roof because the edge flashing is feathered to either the trim deck, the corrugated or the clip lock profile.

[00:09:13]Now, what if you wanted to install the super wide tray flashings not up and down the roof but across the roof in a transverse direction? So what you can do is there are two flashings that has the flexibility to be installed on the edges of the super wide tray flashing. And what you do then is that you can put these fleshings on the edge. The super wide tray flashings go across the roof.

[00:09:44]And what you do is you do a side bend.

[00:09:47]And the side bend can then go on either side of the roof or both sides. and it will create an apron on the upstream side or it can do something else on the downstream side. Now, one critical thing to remember when you install these tray flashings in a diagonal or in a transverse direction is that the sequence of laying these flashings really matter. Because what you need to do is you need to always have this particular edge of the roof on the upstream edge. Because this means that if the water is actually deep enough to flow over the edge rib, it doesn't go in through the lap even though we should seal the lap when we install the fleshings. So these six standard fleshings gives us the flexibility to do any sort of super wide tray flashing in whatever configuration you like. So, how does this work in practice? Now, we had this roof here that had a leaking soaker gutter. As you can see, um should have been a box gutter there. They didn't put a box cutter in. It was too difficult.

[00:11:09]So, we ended up with a solution of installing a tray flashing, a super wide tray flashing to eliminate the soaker gutter altogether. So, what we decided to do was put the tray flashing in at an angle. And what this does is that it doubles up as the stiffener on these previous installation we've done, we've just added an angled stiffener on top of the super wide tray flashing. But in this instance, the stiffness is actually incorporated in the tray flashing. And so the tray flashings has got a stiffener that runs at an angle.

[00:11:46][clears throat] And what it also does is it's a guide for the water. So if you look at the water flow on this particular super wide tray flashing that we did, you can see that the water hits the joints of the super wide tray flashing. And the joints actually performs as a water guide and guides the water out of the corner of the roof and then onto the adjacent roof sheets where the water can then drain away to the gutter. Now, here's another example that we've used this super wide tray flashing. And the question on this job was, how do we eliminate this problematic valley, a very low pitch valley that had a stay right in the middle of the valley? And what we did was we came up with the solution of using the design concept of the super wide tray flashing. And we put two pieces of tray flashing together. And that allowed us to totally eliminate the low pitch valley. And that made flashing and waterproofing of this particular awning roof a lot easier.

[00:12:57]So now if you come on a job and it requires a super wide tray flashing and you get these flashings in your delivery, you now know what to do. So now that based on our training video, you know a little bit about the super wide tray flashings. Back to this roof with the super wide tray flashings, it brings up an important concept because eliminating box gutters from flat roofs is a genuine need. And if we use our super wide trade flashings concept to achieve this, then surely there's a little niche in the market for these types of flashings. Thanks.