skylight install (horizontal vs vertical)

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  #1  
Old 03-07-08, 06:22 PM
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skylight install (horizontal vs vertical)

I am putting on addition and there will be skylight. The plans show the skylight vertical (long axis up/down). the framers put opening that way but I noticed on box that it said two part numbers and when discussing with them, I found out that it could have been put horizontal (long axis side to side). It is Andersen SKS 2446/4624. I would really prefer it horizontal--4624. I may redo the framing in the area to make it fit. I asked my general about having it done and he said that the bigger expense is going to be from roofer. Why would this be? I see that we have an Andersen shingle flashing kit for it but have not opened the box to see if it can be used either way or only for vertical install. I tried to call Andersen but got some girl who really didn't know anything. Also, would I be using the fold out mounting brackets or straight brackets? It is a little confusing in the literature I did find. One place it said straight brackets are for certain flashing types and someplace else it says that vertical install uses the fold out ones and horizontal uses straight one? I have about 4/12 pitch and will have shingles.
 
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  #2  
Old 03-07-08, 07:22 PM
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I would stick with the vertical. On horiz. roofer will have to
build up larger dam areas to direct water away & around skylight. Vertical will provide less area & less problem of water entrainment.
 
  #3  
Old 03-07-08, 07:22 PM
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OK, I opened up one of the shingle flashing kits. It does not appear that it would work with horizontal application since the sill flashing and head flashing are only wide enough for the short sides. According to the Andersen rep I spoke with earlier, this is the only flashing kit? so how do you flash a horizontal application? Maybe have to make your own? And that could be the extra cost. Seems strange that they wouldn't make a horizontal shingle flashing kit.
 
  #4  
Old 03-07-08, 07:27 PM
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the skylight is actually trying to direct light into another room-the kitchen-not the room that it is installed in-the dining room. Can't install in kitchen since there is 2nd floor over it, but not in dining room. And putting it vertical means that it is over dining room table and therefore can't put up light over the table. Horizontal really works better for our layout and what we are trying to do with the skylight.
 
  #5  
Old 03-07-08, 07:35 PM
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Skylights are notorious for leaking--stick with the vertical
 
  #6  
Old 03-07-08, 07:42 PM
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With horiz. - make sure you get a special warranty
 
  #7  
Old 03-07-08, 08:33 PM
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If you can return your skylight, then call Velux and ask them what they now have available. They have a nice flashing kit. Also for more light, into the home "flair" your top and bottom framing header between the rafter rough openings. Your framer will know how to do this. Works good too. You need to stay vertical though. Horizontal traps everything, snow, leaves, etc. Good Luck.

Indii
 
  #8  
Old 03-08-08, 07:18 AM
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Got to agree w INDII...

Velux will probably have something to better fit your needs.
Andersens aren't bad, just not as good. Velux basically invented skylites as we know them.

Also, have you thought of maybe 2 smaller skylites? 2 FS2222's or equivalent? It might even simplify your framing a bit. You would have to skip one truss/rafter because of the flashing width though.
 
  #9  
Old 03-08-08, 07:44 AM
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thanks for all the replies, but I am limited since we already have the unit. I can't "eat" the cost of another window. I already had to with a $700 unit! Although those were special order (between panes grills)and contractor said they could not be returned. Maybe skylight could be returned? I will check with him and check velux website.

I understand that the chances of leaking are greater with horizontal, BUT, the location of this skylight on my house is such that I don't really think it will be issue. I would post picture if I knew how. It will be on a shed roof way at top near where the roof ties into a wall (my 2nd floor wall). The second floor also has a shed roof, the overhang being about lined up with the top edge of skylight. So most of rain will be captured by gutter on the upper shed roof and taken away from skylight. And there are not trees near this area. leaves would have to come from other side of house and because of the overhang of upper shed roof, would not likely pile up near skylight. And I will have a window in the 2nd floor room that will give very easy access to skylight (it will be practically reachable from inside the house) if I need to remove leaves, etc.
 
  #10  
Old 03-08-08, 08:46 AM
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@gunguy45
In case your are curious--skylights were invented by a guy
named Max Waserman who started the Wasco Co (still in business today ) He stole the idea from the bubbles used on WW2 bombers--all Co's came later especially flat panels like
velux
 

Last edited by j HOWARD; 03-08-08 at 09:54 AM.
  #11  
Old 03-08-08, 09:30 AM
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"Does my house suck?"

Velux and others do skylights like you described. They are typically in banks say of two or three. The flashing kit has a channel between them. There are lots of opportunities for the more complicated flashings to leak, especially when leaves and debris collect.

Oddly enough we had better luck on commercial buildings with the cheap bubble skylights. We just had to have the velux skylights sash glazing redone because it was leaking. We had some commercial aluminum/glass skylights fail after 15 years. These were fixed skylights. Another building had plastic bubbles that were still going strong after 20 plus years.

Part of your question is whether you need opening or fixed skylights and what type of room you had. All three of the buildings had low pitched membrane roofs and the flashings were in the roofing. From our experience I would say that comp roofs and membrane roofs were the least problematic. Tile, shake, and wood shingle roofs are the most problematic.

If you use a wide flashing above the skylight you would probably have to have a special flashing made that had a "cricket" built it going up from the center. This would turn the water coming off the roof to the outer edges.

Another thing that you should consider is whether your house is under a negative pressure. In this situation lower pressure on the inside of your house is trying to suck air/water from the outside. This means any small leak or crack is an opportunity for a leak.

An architect asked me to take a look at a house that was leaking on a high vertical outside window wall. While we were there a gust of wind came up and a stream of water the size of a small finger came out of a window corner. When I told the homeowner what happened he questioned, "Are you saying my house sucks?"

Jim
 
  #12  
Old 03-08-08, 09:45 AM
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One thing about installing the skylights perpendicular to the slope of the roof: if the skylight is more than 30" wide in this dimension, a literal reading of the IRC requires a cricket:

R905.2.8.3 Crickets and saddles. A cricket or saddle shall be installed on the ridge side of any chimney or penetration more than 30 inches (762 mm) wide as measured perpendicular to the slope…

And despite that fact that only the most conscientious roofers install water diversion above such skylights, the code makes no exception for this application and this requirement is in addition to the factory supplied or recommend flashing.

So even though the "required" crickets are seldom installed, at my inspections I note skylights when they are absent – because when that skylight starts leaking, and it's not installed with a cricket, I may end up on the wrong end of a lawsuit unless I've noted this I my report - along with whoever installed the skylight sans cricket in the first place, even if it passed municipal inspection....

The same, BTW, for the absence of a required curb on low-slope roofs - which may apply is the case of hammerash's shed roof.
 

Last edited by Michael Thomas; 03-08-08 at 01:30 PM.
  #13  
Old 03-08-08, 10:20 AM
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Sorry j Howard

Have to disagree with you, but not too much.

I should have qualified my statement a bit..."Velux basically invented 'flat glass' skylites as we know them today"

Velux http://193.163.166.98/COM/history/#

Wasco http://www.wascoskylights.com/about/company_info.php

If you look at the company history links here, Wasco didn't come out with even their dome style until 1949, while Velux developed what they called a 'roof window' in 1942. Wasco didn't even market a flat glass skylite til 1974.

Looks like Wasco was probably the inventor of acrylic dome types tho.

I guess what I think is most impressive about Velux is that their better products don't rely on any roof cement or caulk to seal. Its all mechanical, like any good roof flashing job.

In many parts of the world, Velux is used generically as a name for skylites, much like 'kleenex" is used for paper tissues.
 

Last edited by Gunguy45; 03-08-08 at 10:36 AM. Reason: oops, forgot the links/date correction
  #14  
Old 03-08-08, 10:32 AM
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Modela

I can completely agree with you about the domes vs glazed skylites for commercial apps. Do you think it it is due to the types of roofing used in commercial buildings, plus the extremes in pressure changes (like when you open an entry door in a large office building and almost get blown out the door)? Since the domes are basically one solid molded piece, with more 'give' to them, it would make sense to me.

I just don't like the hazing effect i've seen on most of the bubbles after a given number of years. And they still market so many of the non-energy efficient ones, people get sucked in by the low price and then are so turned off of skylites in general, its a shame.
 
  #15  
Old 03-08-08, 10:33 AM
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Maybe I should have said the plastic dome business was a huge market for many years-flat panels not much until later.
We killed the suns rays on the Astro dome with Hillsdale Ind. co. dome skylites but we gave them astro turf.
You have no idea how happy I am that I am out of commercial constr. & retired 9 years after 45 years in the rat race
Amen....................
PS: we never heard of Velux in the commercial business.
We did get into residential skylites later & got out fast--nothing but leakers in the old days.........
 

Last edited by j HOWARD; 03-08-08 at 12:22 PM.
  #16  
Old 03-08-08, 10:39 AM
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Is curb required for 4/12? Where can I see a picture of a "cricket" that everyone is mentioning. I didn't see it on velux or andersen sites.
 
  #17  
Old 03-08-08, 11:10 AM
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A curb is basically made to elevate the skylight above the roof line. Some skylights like Velux have built-in curbs and use their flashing systems. If you want wide skylights with Velux you would typically gang them side by side using their flashings systems.

Others like dome skylights require a curb to be built
(http://www.bristolite.com/HTML/INDEX2_PROD_R.HTM).

A cricket is an inverted funnel shape that goes on the upward roof side to keep water from pooling on top. You can see a chimney cricket at http://www.lowes.com/lowes/lkn?actio...ngNewRoof.html. A skylight cricket is similar and is needed on wide skylights to keep water and debris from building up.

Jim
 
  #18  
Old 03-08-08, 11:15 AM
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Bristolite Follow-up

It looks like the bristolite like is not working but you can go to www.bristolite.com and go to standard products. Their data sheets show a curb detail.

Jim
 
  #19  
Old 03-21-08, 10:05 PM
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I'll start by saying windows do not belong on roofs. install the skylight vertically, use the flashing kit provided and under the flashing kit use a ice and water shield (rubber adhesive membrane). A 4/12 pitch roof is the minimum requirement for an Andersen skylight for proper water deflection, so you should be fine. a note to the roofer is to leave 1/4 gap between the shingles and the skylight to prevent shingle buckling. Do not butt the shingles tight to the sides of the skylight. They need to be able to move during weather changes.
 
  #20  
Old 03-23-08, 04:02 PM
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with a name like andersentech should you be saying that
windows don't belong on roofs ?
 
  #21  
Old 03-23-08, 05:34 PM
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sometime the truth hurts.
 
  #22  
Old 03-23-08, 10:02 PM
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No he says that because he's probably had to change out more than a few Roof Windows. Andersen literally had hundreds of warranty issues with their roof window. My dates might be inacurate but the roof windows made from around 1982 until 1987 had some serious problems with water leaking around the seal. If you've ever changed a RW4446 on a 12/12 pitch, 16' up in a cathedral ceiling you would say the same thing, Windows don't belong on a roof.

I will say this for Andersen, they took care of them, parts and labor. Andersen's service department is second to none. I don't claim to bleed orange and black, but there's a reason why they are one of the top window manufacturers. Customer Service.

But for a skylight--buy a Velux
 
  #23  
Old 03-23-08, 11:25 PM
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We were in the commercial Skylights & smoke vents.
We went into residenial & got out faster than a cat on a hot tin roof.................nutnnin but leakers..........that was before Velux got really going.......
 
  #24  
Old 08-15-08, 06:33 PM
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I assume the skylight you refer to is a nominal 2' x 4'. I'm having the same problem with the flashing kit for a 2' x 4' Velux. So I'm going to buy the Velux flashing kit for a nominal
4'X4' skylight. This is about $30 more. This way the top and bottom sections are exactly the right length, and I am left with some surplus pieces of step flashings for the sides. Maybe Anderson has similar products
 
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