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Discussion Starter · #1 ·
Hi, How should I flash a window sill bump out that is under the roof overhang. This is not my area of expertise. The rough opening is framed with 2 layers of 2x10's and the counter tops will extend into the sill. The opening is about 45" x 40"

I posted pics, but the forum said I wasn't allow to untill I have 15 posts, so I don't know how to show you guys.


How should I flash the outside of the bumped out rough opening? Tar paper, building wrap? Will I need something more specialized for this. The roof overhang does cover the bump out. Vinyl siding btw.
 

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Use Photobucket to upload the pics and provide a link...but if the overhang covers the window...why should you need any flashing at all?...around the window just use Ice and water shield
 

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Discussion Starter · #5 · (Edited)
Photos

Here are some attached pics. I can't link to photobucket untill I get 15 posts. This is annoying requirement for a newb trying to get advice!

The outside photo is old, now I have 2 layers of 2x10's built up on the inside and the window sill height is the same as the cabinets.

What should I wrap the outside of the exposed framing with? I plan to put trim around the edges but I didn't know how to seal this type of window from water. I'm in Seattle.
 

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KemoSabe
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OK, here is my take.
1. Remove existing siding to a coarse below the window.
2. Bend an L flashing from the lock on the siding up the wall and out to the face of the box. Run it 3" past each side, cut and fold the 3" overhang up the wall.
3. Bend a similar L to run into the inside corner on each side, run 3" long on each end, cut and fold each overhang flat to the wall.
4. Now bend a counter flashing to cover the sill, face of box and return 3" under the box.
5. Do the same detail on the sides.
6. Caulk entire perimeter of window opening, leaving a few small weep openings along the bottom, assuming the window will have nailing flanges. Install window.
7. Now is the time to fit a flashing at the top of the box that will cover the nailing flange as well as shed water from getting behind it from above.
8. I personally would trim the entire enclosure with a vinyl trim board product.

NOTE: If you remove the siding and find felt paper behind it, it will be in good condition.
If you find Tyvek, please open a thread stating the condition of the product.:thumbup:
 

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Discussion Starter · #9 · (Edited)
Should I wrap the outside of the "box" with tar paper before I put on the 3" metal flashing?

Here are some people doing a similar window bump out but it's just a photo gallery, no step by step instructions.

home-and-garden.webshots.com/album/48273144EDvCmx

BTW, thanks for the reply.
 

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Capra Aegagrus
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Should I wrap the outside of the "box" with tar paper before I put on the 3" metal flashing?
Not necessary, but you can if you want. By the time you get all of that metal on there, you will have completely enclosed the "box".

I'm trying to figure out why you extended it so far outward.
 

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KemoSabe
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Should I wrap the outside of the "box" with tar paper before I put on the 3" metal flashing?

Here are some people doing a similar window bump out but it's just a photo gallery, no step by step instructions.

home-and-garden.webshots.com/album/48273144EDvCmx

BTW, thanks for the reply.
Paper would not be a bad idea if you can keep the bends clean and sharp. I've creased it in a metal brake before.:thumbsup:
 

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Ok, here you go, i think i have the picture-- are you trying to avoid removing the siding? If you are, it will be difficult to protect the area between your framing and the j-channel.
 

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KemoSabe
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Run your sill flashing in at least 6 or 8 inches and make sure you really seal the bottom of the granite at the window/flashing location.:thumbsup:
 

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That last photo shows wood siding brought tight to the box, that detail is very different than your condition with vinyl and a j channel
 
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