ZIP Sheathing with metal roof; how to tape offset cleat at eve flashing?
My metal supplier doesn’t have any experience with installing metal panels directly to a ZIP roof deck, but has no issues with it. Huber says it’s fine, and a few of the metal roof manufacturers have signed docs accepting the practice.
Huber recommends using ZIP tape over edge flashing, gable flashing, etc. Perfect, easy as pie, just tape over flashing.
I’m using an offset cleat on the eve edge, over top a pre-hung gutter flange (the gutter has a flange that mounts flat to the roof deck. I’m planning on taping over the gutter flange edge, as would be done over any eve trim.
But, most all of the roofing install manuals specify that the offset cleat is bedded in butyl tape (double sided); I’m assuming this is because of wind-blown rain?
I can use the butyl if needed, but the butyl would have to be applied to the ZIP tape on the gutter flange.
Representative eve detail of offset cleat with traditional underlayment:
https://f.hubspotusercontent30.net/hubfs/6069238/images/trim-flashings/standing-seam/detail-wsd-d3-1.jpg
It looks like Huber says to just tape the upslope edge and call it good….?
Rather limited (but maybe similar) detail from Huber:
https://www.huberwood.com/uploads/documents/technical/documents/MP-1.1-Metal-Panels-over-ZIP-System-Sheathing-Detail-Roof-ZIP-System.pdf
The full stackup would be:
ZIP panel
Gutter flange, edge taped onto the ZIP panel
Gutter straps, screwed flat to the gutter flange and roof deck
Offset cleat, edge taped onto the gutter flange
Metal roof panel, hemmed to the offset cleat
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Replies
chrisd_innc,
I don't like to rely on butyl tape under gazetted fasteners where moisture may get below what is being attached. I take a gasket off another fastener and place it on the screw shaft under the material, so it gets sandwiched between it and the substrate below. That's what I'd do with the cleats. It eliminates any compatibility concerns.
The one downside of gutters that mount to the roof deck is that it makes them very difficult to replace, and gutters are one of the most vulnerable and fragile parts of the building exterior.
Ah, so it sounds like the butyl tape detail is a screw penetration seal of sorts? Makes sense, if the main source of bulk water would be from the eve edge. Maybe I'll wait to apply the ZIP tape until after the cleat gets attached, so the butyl tape can bond to the gutter flange instead (if I'm sticking with the butyl). Huber does seem to call out butyl as being compatible with their products, but.......
The replacement issue had definitely occurred to me, after ordering everything. I do like that it protects the fascia with a lack of fastener penetrations though.
I guess if things get ugly in the life of the gutter, I can remove it off the eve with the electric shear (maybe convert some of it to a drip edge over the fascia wrap) then add a bracket-hung gutter. Luckily this is only a 12x24 shop building, so the work is scaled to a manageable size.
This is the first standing seam roof that I've installed, so I'm trying to fill in the detail gaps. I'm not scared of sheet metal, I've just never used it for a roof. This entire shop build is about trying new things.
chrisd_innc,
I got into installing my own metal roofs partly because the labor component seemed to me inordinately high, but also because it a really fun and satisfying job. I bet you end up doing another one.