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skylight flashing


John Dirks Jr
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What percentage of the time do you find skylights that have their flashing installed correctly and to the best practice?

Can you post some diagrams of what proper skylight flashing should look like?

Thanks

Most of the skylights that I see are properly flashed.

The flashing should look exactly like chimney flashing.

- Jim Katen, Oregon

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When Velux skylights came into vogue fifteen or twenty years ago and were sold at local supply houses, the products and installers were both sub-par. But the learning curve was relatively short and leakage isn't much of a problem anymore . . . uh, like Jim and Randy said.

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Should you always see the step flashing on the side like in this picture?

For most curbed skylights, yes. There are some self-flashing ones that don't require step flashing.

The one problem I see with the diagram you posted is that it doesn't show a gap between the shingles and the top of the curb. There should be a couple of inches of exposed head flashing on the top side of the curb so that pooling water doesn't wick up between the flashing and the shingles.

- Jim Katen, Oregon

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For most curbed skylights, yes. There are some self-flashing ones that don't require step flashing.

Like the crappy manufactured home one's?

The one problem I see with the diagram you posted is that it doesn't show a gap between the shingles and the top of the curb. There should be a couple of inches of exposed head flashing on the top side of the curb so that pooling water doesn't wick up between the flashing and the shingles.

I don't know how many others do this, but I will often recommend trimming back shingles at all flashing areas. The installers most often butt the shingles too tightly against flashing at sidewalls, sides of skylights, pipe jacks etc. The problem is that debris can catch in these areas; moss then grows and can be problematic.......

On another topic, does anyone have a detail showing how to properly install a cricket/ saddle on a skylight that is wider than 30"? Never seen a cricket/ saddle installed at these areas, and can't figure how they are going to do it without substantially rasing the entire curb.

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Like the crappy manufactured home one's?

No, those leak even if they are put in right. Veluxe makes a gasketed skylight called the Q series. Wasco as been making their E class unit for 20 years now. Check them out to see what they are all about. I have installed both, and they work pretty well.

Tom

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The "easy" way to do that is to break some sheet metal/aluminum into a cricket. I have a guy that does it for me. You gotta have some sheet metal guys out there, don't you?

Skylites >36" wide are pretty scarce. I've got 2 of the largest Velux available; I think they're about 40", no crickets, no leaks.

I'm a very big fan of WR Grace all around the perimeter of the lite before the shingles or flashing even go on. That pretty much makes leaks impossible.

I've got 6 Velux lights on my crib. Never a drop in 18 years.

Also, if the light is on a roof pitch <3:12 (I think that's right...), you have to have an auxiliary curb to bring the pitch up so the glazing drains.

Velux has special packages for all those conditions. All sorts of gang flashing packages, curbs, and related equipment are available, and they all work.

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As a builder, all I used were Velux products after I discovered them. Prior to that, I built curbs and had a sheet metal shop make custom flashing that did what Velux flashing kits did right out of the box. I consider Velux products as virtually foolproof if you read the instructions. Unfortunately, not all installers do.

Check out the photo below from the home of a retired "builder". This mess was easily visible from the deck even w/o walking the roof, and it was about a ten year old installation. Yes, there were waterstains on the ceiling.

But it could be worse. I went on a roof of a home I was building exactly 20 years ago where I was checking out the work of a roofer I hadn't used before. On the positive side, he had used the step flashing, and it was under the shingles as it should have been. Unfortunately, he had installed it where the top edge of the lower sections was to the outside of the lower edge of the upper ones. In other words, water would be guaranteed to get where it didn't belong. I attempted to educate him in a courteous manner; strangely enough, he wasn't interested in learning anything from me that day.

When I started learning the home building business, my dad told me that roofers were the lowest rung on the construction ladder. For years, I considered one with all his teeth and a working telephone as almost a godsend. Seems a shame that something that important is left largely in the hands of guys who often don't have two functioning brain cells working in concert.

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tn_200935214348_HPIM0271.jpg

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Keven,

What's wrong with the flashing...[:-slaphap

I pulled up some installation instructions for Velux: http://www.domwebx.com/inet/techdocs.ns ... penelement

They show that shingles must be installed within 0- 1/4" at the side step flashing areas. This must be for cosmetic reasons only? I say it's just plain dumb to butt the shingles against the flashing (moss./pooling reason). Can anyone think of any reason why holding out the shingles say 3/8" would be a problem?

Also, they require a rain/ snow diverter on any roof between 12/12 and 20/ 12--------- woops, never seen one installed.... I can't wait to call that one out some time

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Keven,

What's wrong with the flashing...[:-slaphap

I pulled up some installation instructions for Velux: http://www.domwebx.com/inet/techdocs.ns ... penelement

They show that shingles must be installed within 0- 1/4" at the side step flashing areas. This must be for cosmetic reasons only? I say it's just plain dumb to butt the shingles against the flashing (moss./pooling reason). Can anyone think of any reason why holding out the shingles say 3/8" would be a problem?

Seems to me, the more gap between the edge of the shingles and the flashing, the greater the chance that water will hit the flashing and seep under the shingles, rather than run off on top of them.

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Tom:

Veluxe makes a gasketed skylight called the Q series. Wasco as been making their E class unit for 20 years now. Check them out to see what they are all about. I have installed both, and they work pretty well.

Thanks for the info.

The Velux self flashing skylight makes me nervous just looking at it. Here's the link to that one: http://www.domwebx.com/inet/techdocs.ns ... penelement

I can't say I've ever seen one of these installed (at least that I can remember). I guess the upside is you don't have to frame a curb. I assume that the reason that I don't see these used is their cost. Anyone know the price difference between self- flashing and non self- flashing Velux units?

I noticed that on this self flashing skylight they do not allow it to be used under 3:12 roof slopes, while non self flashing units can (with ice/ water shield)

The "easy" way to do that is to break some sheet metal/aluminum into a cricket. I have a guy that does it for me. You gotta have some sheet metal guys out there, don't you?

A house last week had a skylight that was really wide. (new construction). I told the client not to worry about the lack of a cricket on it because it started only a couple courses down from the ridge.

I'm just trying to picture how to comply with current building code that indicates the need for a high cricket on a steep slope. It's gonna look really weird.

Kurt,

Jim probably knows of someone that does quality sheet metal work, but I don't. I rarely see any sheet metal work on residential construction, and the stuff I see is usually awful.

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Seems to me, the more gap between the edge of the shingles and the flashing, the greater the chance that water will hit the flashing and seep under the shingles, rather than run off on top of them.

That could be the reasoning, but what about all of the other keyholes or shingle joints on the rest of the roof? Water is going to run beneath the exposed sections of shingles, which is why fastener placement is critical. On site- built flashing, I like to see the head flashing run out a couple of inches past the top corners, which would keep most roof drainage away from the flashing. I guess on the Velux units, a lot more water will be shedding up against the flashing due to the design....

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. . . I'm just trying to picture how to comply with current building code that indicates the need for a high cricket on a steep slope. It's gonna look really weird.

It's not a skylight, it's not very big and it's on a standing seam roof, but here's what it might look like:

Download Attachment: icon_photo.gif Leetle Cricket.JPG

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Jim probably knows of someone that does quality sheet metal work, but I don't. I rarely see any sheet metal work on residential construction, and the stuff I see is usually awful.

Pioneer Sheet Metal does pretty good work.

Washington Roofing's metal work always looks nice. I don't know if they do it themselves or if they sub it out. You might call Harold Washington and ask.

I once had NW Gutters do a small amount of custom sheet metal work for me --that was close to 20 years ago, but they were very good.

The last time I needed some custom flashing, I called my HVAC guy, Bob Hedin, in Gaston. I just gave him a drawing of what I wanted and he origamied it up in a day.

- Jim Katen, Oregon

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Are/ will you be calling out the lack of crickets at wide skylights?

I woudn't on the velux units unless they are installed outside the stated pitches. The building I work in (day job) has 14 velux 606's, the 40" ones without crickets and no leaks after 14 years. Curb mounts or other custom flashing jobs I suppose it would depend on what they look like.

I wouldn't hesitate to use a self flashing skylight on new construction and prefer the wasco e class for this, but for retro fit the velux s series is the way to go.

Tom

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Thanks Jim,

That's a cute little cricket. I just think that on a 2x4 or 2x6 framed opening, it's nearly pointless to have a cricket. Now, if someone want's to use some 2x12's a cricket would probably do some good.

Are/ will you be calling out the lack of crickets at wide skylights?

No. I think it's a silly requirement.

- Jim Katen, Oregon

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