Skylights: double up the rafters?

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Hi,
My carpenter just told me that if I am having a skylight put in between two rafters, I should double up each rafter because the hole in the wall weekens the roof. Do you agree with that?
Thanks,
Aaron
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Aaron,
I'd be looking for a new carpenter. This statement by s/he, speaks volumes about their knowledge.
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On Fri, 24 Oct 2008 18:57:40 -0400, Toffee Monday wrote:

Reasoning is incorrect, but I would double up the rafters to stiffen it up to guard against flex-induced cracking. I like to overbuild so I don't have to do any repairs later.
Mike D.
P.S. get off googlegroups. Many a wise man blocks them out and your post is only seen if a less wise person fails to filter them.
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You miss what the OP said, about in between rafters. Doubling up the rafters will no absolutely nothing, but waste time.
If you're referring to me about googlegroups, you might what to learn about servers. I'm not posting through Google.
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Mike Dobony wrote:

Skylights often leak, so the reasoning may be that if there is a leak and rot later on, doubling up will help ensure strength and support of the roof.
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Skylights leak, simply because they're not installed properly. I had one architect tell me all skylights leak, he wondered why I looked at him like he had 4 heads. Then I explained about installation.
Doubling up rafters offers nothing. If this were the case, every penetration would need doubled up rafters. Such as vents, soil stacks, chimney flues, etc. Take a peek in your attic, you'll not see a doubled up rafter at any penetration, unless you have an over-sized chimney spanning several rafters.
When installing skylights, you do need to put blocking between the 2 rafters.
People tend to think because the sheathing ends at a skylight, you need double rafters. If this were the case, you would need double rafters on the entire structure, since sheathing starts at the eave & ends at the ridge. In other words, it has to start somewhere, and end somewhere, and there's no blocking at the eave or ridge.
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On 10/24/2008 3:40 PM Aaron Fude spake thus:

Yes.
--
Washing one\'s hands of the conflict between the powerful and the
powerless means to side with the powerful, not to be neutral.
  Click to see the full signature.
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Wrong information, for the question asked.
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Normally, the rafters are not doubled up. A typical skylight requires one rafter to be cut to make a large enough opening, and that is what is done. Then the opening is boxed in to the right size using a doubled cross piece the same dimension as the rafter at the top of the opening and at the bottom that is tied in to the rafters on either side. That provides sufficient structural integrity. In essence the cut rafter is still there and carrying load, it's just tied in now with the skylight framing.
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I'm very proficient in framing, you needn't attempt to tell me how framing is done.
You missed the OP's question, I suggest you re-read it. They're not cutting any rafters.
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Last time I checked, people in this thread were giving advice to the guy who made the original post, not you, so no need to get testy.

Well, I did mis-read the question a bit. And you could certainly take the question that way. However, just because some homeowner on here says they are putting a skylight between 2 rafters, doesn't mean they aren't cutting one out in between the two. If you cut one in the middle, you still have a skylight between two rafters. No mention was made of the size of the sklight or the spacing of the rafters. Just that fact alone should tell you that the person seeking advice may not fully understand the situation.
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You replied to me specifically, not the OP. Look at the thread, if you wanted to reply to the OP, don't do it through me.
LOL, you're trying to tell me not to get testy? I have news for you, don't reply to anything, if you're going to attempt to dictate the responses.

If you want to read something into the question posed, that's your right.
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I've been a carpenter for 30 years. I have yet to see a communities building code that doesn't require doubling up the rafters. It's typical for bigger towns and cities. Lou
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Even if it isn't code, there is nothing lost by over engineering a modification, much can be lost by doing the minimum or worse.
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Absolutely not. I call you on this. You may have been a handyman for 30 years, a carpenter, no. There's no code which calls for "doubling rafters", in the OP's situation.
In fact, type into your favorite search engine on how to install a skylight.
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Call me on it all you want you moron, there are codes on this. It has to do with any sizable opening in the roof whether for a skylight, chimney, or even a dormer. Not only have I been a card carrying carpenter for 30 years, I can out build you, out work you, and apparently out think you any day, any time, any where. You are obviously nothing more than a hack with daddy's hammer. Get back behind the McDonald's counter where you belong. Lou
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Geez, I seemed to hit a nerve! BTW, there's nothing wrong with being a handyman, if you have a clue!
Now I know you have a reading comprehension problem, but the OP said they were going between rafters. Since you obviously do not know how to use Google, I took it upon myself to do part of your homework for you.
Here's an article from Fine Home Building, page 86 will help you with your lack of knowledge. http://tinyurl.com/6bk4c8 -OR- http://books.google.com/books?id=_-F9Ni7rg04C&pg=PA81&lpg=PA81&dq=skylight+install+double+rafters&source=web&ots=aQrLTsVRfU&sig=PANZwIi7xkQK4qt_S6237xtoz0o&hl=en&sa=X&oi=book_result&resnum=2&ct=result#PPA86,M1
Please quit making yourself look like a fool! Anyone with any knowledge knows if you've been a card carrier for 30 years, please 4 years of apprenticeship, should not still be doing any type of framing work! Your agility is shot, and you had better moved on to at the very least, supervision!
Now, it's time to show that code you been trying to play or shut up!
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Geez, I seemed to hit a nerve! BTW, there's nothing wrong with being a handyman, if you have a clue!
Now I know you have a reading comprehension problem, but the OP said they were going between rafters. Since you obviously do not know how to use Google, I took it upon myself to do part of your homework for you.
Here's an article from Fine Home Building, page 86 will help you with your lack of knowledge. http://tinyurl.com/6bk4c8 -OR- http://books.google.com/books?id=_-F9Ni7rg04C&pg=PA81&lpg=PA81&dq=skylight+install+double+rafters&source=web&ots=aQrLTsVRfU&sig=PANZwIi7xkQK4qt_S6237xtoz0o&hl=en&sa=X&oi=book_result&resnum=2&ct=result#PPA86,M1
Please quit making yourself look like a fool! Anyone with any knowledge knows if you've been a card carrier for 30 years, please 4 years of apprenticeship, should not still be doing any type of framing work! Your agility is shot, and you had better moved on to at the very least, supervision!
Now, it's time to show that code you been trying to play or shut up!
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Geez, I seemed to hit a nerve! BTW, there's nothing wrong with being a handyman, if you have a clue!
Now I know you have a reading comprehension problem, but the OP said they were going between rafters. Since you obviously do not know how to use Google, I took it upon myself to do part of your homework for you.
Here's an article from Fine Home Building, page 86 will help you with your lack of knowledge. http://tinyurl.com/6bk4c8 -OR- http://books.google.com/books?id=_-F9Ni7rg04C&pg=PA81&lpg=PA81&dq=skylight+install+double+rafters&source=web&ots=aQrLTsVRfU&sig=PANZwIi7xkQK4qt_S6237xtoz0o&hl=en&sa=X&oi=book_result&resnum=2&ct=result#PPA86,M1
Please quit making yourself look like a fool! Anyone with any knowledge knows if you've been a card carrier for 30 years, please 4 years of apprenticeship, should not still be doing any type of framing work! Your agility is shot, and you had better moved on to at the very least, supervision!
Now, it's time to show that code you been trying to play or shut up!
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Aaron Fude wrote:

ridge. A typical residential skylight, no more than 24x48, will be no problem unless the roof is weirdly framed. It is usually a good idea to box the 2 rafters around the hole, though. Keeps the area stiffer, and makes the skylight less likely to leak. I'm old fashioned, I like to see a box frame extending through the roof, with the metal skylight frame several inches above the shingles. Makes it easier to change down the road when it fails, since the skylight waterproofing is above the main flashing where the shingles and box frame come together. It also reduces the chances of ice dams on the skylight. Unless you have a cathedral ceiling, you'll be framing up a tube down to the finish ceiling anyway.
-- aem sends...
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