Flangeless Windows – Drip Cap/Head Flashing
Tim_O
| Posted in General Questions on
I am working through some of the siding details I should have given more thought to previously. We have Euro style flangeless windows, set about 2″ back inside the window RO. Face taped all around to the WRB. Then 1×3 strapping for a rain screen. I intend to use 1×4 cedar to make an extension jamb and butt the siding against that, or leave a slight reveal gap.
All that said, as you can see, we have done most of the rain screen details already. I’m thinking I should have put a drip cap tucked under that top horizontal 1×3. How have others detailed a drip cap? Attach it to the 1×3 and back tape to the WRB over the top of the 1×3?
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Replies
Tim,
The rain-screen furring should all be vertical with no horizontal pieces above or below the window. The head-flashing should be lapped by the WRB, and the trim held up 1/8" above the flashing to allow moisture to drain.
The furring being all vertical makes sense. The framer might not be so happy about removing the horizontal ones. Shouldn't the drip edge go over top of the trim? I could tape the drip edge to the WRB.
Tim,
Where the head-flashing goes depends on whether the trim is installed directly to the WRB, on the furring, or on top of the cladding.
- If the trim is on the WRB, the head-flashing should be installed above it.
- If it's to be on the furring, then it goes above and the furring strips need to be broken so the head-flashing can go back to the WRB.
If it's on top of the cladding then it goes below.
With a rain-screen, including end-dams is a good idea. Bed the head-flashing in caulking, and tape the vertical leg to the WRB.
https://hammerandhand.com/best-practices/manual/1-flashing/1-2-head-flashing/
This makes sense. I sketched up a picture in PPT, I'm no CAD jockey, haha.
I think I need the horizontal buttons removed unfortunately, to make this work.
Your detail is what I would do (and have done.) Malcolm is right; you can't have a continuous batten above the windows; I have seen that result in moisture problems more than once. I project the jamb extensions beyond the face of the siding since achieving a flush condition is very difficult. I leave a gap between the siding and the cap flashing.
Another way I have done it is to stop the extension jambs at the back of the siding, and run the siding over the jambs. That requires a drainage gap and flashing between the back of the siding and the head jamb.
Thanks Mike, I will work with the framer to pull those off and go with my detail.
I need to figure out how best to handle the fin jamb extension with the external roller screens I have mounted. If you were to case the window in addition to the jamb extension, where would the drip edge sit in that case?