Exterior trim details for round window and metal siding
Hi all, I’m installing a “outie” round Upvc window (flush with exterior insulation), then 1/2” furring strips and vertical metal panel siding. My original trim detail is unfortunately no longer possible and I’m looking for some guidance on a new plan!
The original plan was to first install a custom round pvc casing, matching the depth of furring…1/2” (this is already fabricated and on site). Overtop of this would be a custom round metal j-channel (with a 1” reveal of pvc casing) that would accept the cut metal panel. Alas, my local sheet metal manufacturer cannot accommodate the profile I need on his 3d machine.
What are some other options (ideally still using the pvc casing on site)?
1. Could a round j-channel be fabricated by hand instead? It seems complicated to end up with a front “leg” with a paintable finish.
2. Perhaps copper? But I’d have to separate it from the steel panel into avoid galvanic corrosion (would tape work?)
3. Glued-up wood casing with a 3/4” jamb (to cover the panel edge/ribs)?
Thanks for any ideas!
Adam
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Replies
The only way I can think to make a curved sheet metal J-channel with a profile that deep would be with a metal stretcher to curve 2 pieces of L channel and then welding/bonding them together to form the asymmetric "U". A stretcher can't easily be used on a piece of J channel, because one leg of the "U" always obscures stretching the other leg, which is why two pieces of L channel are needed.
Could possibly do with PVC or another plastic, by thermoforming into shape.
Either method would likely be highly skilled. and expensive.
That's a very deep profile for rolling with a roll former (and custom dies) if using a piece of aluminum extrusion as the J channel, which is similar to what aluminum window companies would do to make a curved aluminum window. Also very expensive for tooling.
There are other ways to make trim for that, I just don't think J metal is going to be a viable option.
Thanks Chris, what are the “other” ways you’re thinking of?
There does seem to be a few places that will do custom curved metal trim; Google "arched j channel metal".
Nice, that’s an option. But wow that’s pricey
Adam,
Ah - the joys of curves!
I'd be tempted to get a ring fabricated from something like 1/8" steel you could get powder-coated. Not cheap, but it is a main feature of that facade.
Thanks Malcolm. That could work, it would need a short jamb leg to cover the panel ends right?
If it was copper, just dreaming here, how would you attach it to the siding but keep it isolated?
Adam,
Would there be any common fasteners? The flashing ring would be fastened to the PVC under it. The cladding gets fastened several inches away. There should be only incidental contact between the two, and the pre-finished panels will have some protection from their coating, but I'm really not sure whether that's enough to rely on.
Something like this?
Adam,
That looks like it would work. Maybe cover the backside of the copper with a piece of peel & stick?
Great! Tape is a good idea. The L- channel should be less complicated to fabricate.