Flashing Around Shop Skylights

[crokett]

Since these are on the shop, figured I'd post here rather than in HI...

The shop has two skylights that I am confident were reused from somewhere so I have no idea on manufacturer. I know about weaving the side flashing into the shingles. My question is on the top and bottom and more specifically the corners. The only skylights I've done were as a teen when we built our garage. Then we had a flashing kit with premade solid pieces that fit around the skylights. I don't have those. What I am thinking is measure the skylights and look for a kit from HD or Lowes. If I can't find one that fits, get a kit and crosscut the top and bottom pieces to fit the width of the skylight so I have the solid corners, then cover the resulting seam with rubber self-stick membrane and/or a solid piece of flashing. I would take the flashing the full width of the skylight. This way whatever water is there would be forced to the sides and drain down as per normal.

What do you think?

[iceman61]

Sounds like you pretty much have it. Don't forget to start out at the bottom & work your way to the top. The bottom & top pieces are a solid piece of "L" flashing 4" wider on each side to go past the skylight. The top of the "L" will get bent around each side of the skylight. From there go up both sides with step flashing, then a solid piece on the top side like you did on the bottom. Seal along the top with silicon caulk. You can use solid flashing instead of step flashing. Adhesive rubber membrane under the flashing or shingles never hurts. My crews use this stuff religiously on a roof. It's great stuff.

[crokett]

Iceman, I understand what you are saying but was concerned about the corners where I am cutting the flashing to fold around the skylight. I don't want to depend on sealant to keep things from leaking, unless I am just overthinking this too much.

[HarmsWay]

HD sells Velux ECL flashing kits.

http://www.veluxusa.com/products/res...ofileRoof/ECL/

[Hellrazor]

Use the peel and stick window flashing to seal everything and then put the aluminum flashing over it.

[pelligrini]

If you can use a flexible type like Tyvek's Flex-Wrap. You would be able to do a continuous piece around the corners. Most of the straight peel&stick products don't do corners well. Having a continuous membrane flashing would be better than doing it in overlapping pieces.

[iceman61]

Iceman, I understand what you are saying but was concerned about the corners where I am cutting the flashing to fold around the skylight. I don't want to depend on sealant to keep things from leaking, unless I am just overthinking this too much.

You won't be relying on caulking on the corners as the metal will wrap around the corner at the top and the flashing on the sides will overlap this. It's just like flashing a chimney.

The caulk is just an extra precaution at the very top edge of the flashing. If you don't use counter flashing over the step flashing, you'll need it, only in an extreme rain event, but it keeps rain from from getting in at the top of the flashing. Again this is only if you don't counter flash.

[crokett]

I guess I am still not getting it. I have problems thinking in 3-D. Supposing the skylight is 24" wide. I cut a piece of flashing that is 36" wide and fold it in half lengthwise. Then I cut the horizontal side of the fold 6" from each end so I can fold it around the skylight. When I wrap it around the top of the skylight, then it is possible for water to drip down at the corner and get under the step flashing, no? Even if I wrap counterflashing around the corner, it can still drip down at the corner, correct?

Maybe I will go up on my roof and see how my chimneys are flashed.

[pelligrini]

Another way I've seen skylights done, as the ones on my house too, is adding another piece of metal Z flashing at the top. If the skylight were 24" wide the piece would be 28 or so. it helps to cover the top corners and divert water away from the sides. It's the last piece to go on.