First off, let me say that this is my first time framing a roof. The roof is a 12/12 pitch and I am doing a simple rafter and joist framing.
I am going to install the rafters soon. When I looked at the different type of hurricane clips (h-clips) there were two different kinds. The first one – lets call it type “A” for discussion sake – worked with a brids-mouth cut into the rafter. H-clip type “B” is designed in such a way so that the rafter didn’t need a birds-mouth cut into it.
Does anyone have any experience or information about the type “B” hurrican clip? If I didn’t need to cut birds-mouths, I could save a lot of time and frustration.
Thanks in advance,
JPS
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Replies
You need to cut the birds mouths
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Why?
I'm not a framer so i don't know the in's & out's of framing.
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
A bird's mouth will place the load of the rafter (and therefore the roof) onto the walls.
Particularily important with a 12/12 pitch, a bird's mouth helps keep the rafters and roof from wanting to slide down the outside of the walls.The heck, you say?
Those swivel thingles might be fine fro down south with a 1/12 or 2/12 roof and no snowloaad, but for real framing, that method would put all the stress on the sheaar strength of the nails and the integrity of the steel in th eclips. I am betting that a thorough read of the Simpson literature would severely restrict how those would be used and where.The cut is there to place the load on the wall.Besides, anybody who cannot lay out and cut a rafter should bnot be building a structure. When it comes to safe construction methods, theeasy way is almost always the wrong way. short cuts just don't cut it.
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Piffin
I sorta understand about the reason(The Physics involved) for cutting the birds mouth. But, are you and Diesel saying that the greater the pitch the greater the need for the birds mouth? Makes sense.
Obviously if you had a 2/12 pitch there wouldn't be a need for a birds mouth at all.
Just curious, I have no plans to do either!
Doug
"You need to cut the birds mouths"
Not if you do a bevel block atop your plate. But, I will be the first to admit, the birdsmouth notch is a wonderful assembly and alignment aid.
the skill and satisfaction that you'll get from cutting and installing good rafters with proper bird's mouth will be worth the time and frustration, even if it won't seem that way until after.
the only one that's hard is the first one. after that it's all template work.
Hey Joe.... can you possibly help this guy out with one of those slick diagrams you do? Your diagrams can explain more than 10 paragraphs ever could.
I'll do something later because I have to go to work. I don't get what the problem is with cutting a Birdsmouth. It's so simple and takes 2 seconds to do and makes it that much easier for nailing in the rafters.I know the guy said that it's his first roof that he's framing so using those simpson ties or whatever he's using, he's going to kill himself trying to hold those rafters exactly in place and then go through the 4 or 5 step process just to nail them in.Joe Carola
That's why I figured you might be able to help. Have a good day at work and don't smash your thumb. :)
Joe -
It is not that I don't want to cut the bird's mouths on the rafters. I want to be as efficient as possible, and if removing a step like cutting the bird's mouths could be removed, then I could save myself some time.
I was planning on cutting brid's mouths without H-clips from the beginning. I had never even heard of a H-clip until the other week. When I went to invesitgate what H-clips were, I saw there were the two varieties. Without being "in the trade" - I am a homeowner building a workshop - I came to FHB to investigate which of the two varieties of H-clips are commonly used and what the pros and cons were for using the type "B" clips that allow the framer to not need to cut the bird's mouth. Obviously the connection is not going to be AS strong as with a bird's mouth, but that doesn't mean that it is still not strong enough.
I think I know the answer now. I am going to frame with the bird's mouth and use the type "A" H-clip.
Thanks for everyone's input. You can see the progress of my project, and the perfectly cut bird's mouth's at http://www.theworkshopproject.com
:-) JPS
"It is not that I don't want to cut the bird's mouths on the rafters. I want to be as efficient as possible, and if removing a step like cutting the bird's mouths could be removed, then I could save myself some time."All I was trying to say was that it will take you 10 times longer by NOT cutting a birdsmouth and also STRUGGLING with the rafter and then trying to hold a rafter in it's EXACT place that it has to go in by marking a line representing the outside of the building.For me since I'm a framer if I was forced to do this I wouldn't mind because I have joist hanger guns that I could stick the point right into the joist hanger hole and shoot the nail in but that's me. I do this every day, you don't. So my advice to you would be to make it easier on yourself and cut the birdsmouths and work like a gentleman and be safe.Joe Carola
cut a conventional rafter..... fully seated on the plate... the reason rafters are cut like that is because it IS the most efficient way to cut and install rafters
and don't refer to them as "h-clips" , it's a dead giveaway that you don't know your jargon.. an h-clip is the clip used to keep plywood aligned in between the rafters.. you should use them too..
but a Hurricane clip is a hurricane clip , not an "h-clip".. you can refer to the "hurricane clip " by it's mfr's designation... like an H2.5 , etc.. but there is a specificity about all of this hardware that becomes important when you talk to Building Inspectors ..
take the time to do it tried and true... there is no short cut to framing a roof with special hardwareMike Smith Rhode Island : Design / Build / Repair / Restore
Mike:
Re the term H-clip see my .14 and his .15 reply above...
Notice I was even polite ;-) I guess I get noticed better when I'm not ;-)
RE the cutting of the birdsmouths, remember, there are people here who frame with screws because it's "easier" than nails LOL!!!
Edited 11/9/2005 8:25 pm ET by Matt
Just as an FYI, I think when most people use the term H-clip they are referring to plywood clips. http://strongtie.com/products/connectors/PSCL_PT.html
BTW - are you the guy who was asking about sizing of your joists, etc? Plans specified DF but you couldn't find any? If so, what did you end up using. I see some pretty pretty joists in those pics...
Project looks to be coming along well.
Matt -Thanks for the website. The H-clips I was referring to are Seismic and Hurricane Ties. You can see the different ones I found at:Type "A"
http://strongtie.com/products/connectors/LTS-MTS-HTS.htmlType "B"
http://strongtie.com/products/connectors/H.htmlI was the one asking about the joist material. After looking and asking around, I went with the SPF joists. I've heard some people have concerns about it, but I also found some that said that SPF were fine. I also found a span calculator from the American Wood Council on it and the calculator said that SPF would work. I put the links to the calculator on my website if you would like to see them. The URLs are pretty long to paste here:http://www.theworkshopproject.com/references.php#generalI also have a thread on Breaktime that tracks the progress I have made on my shop:
http://forums.taunton.com/tp-breaktime/messages/?msg=58466.46JPS
Edited 11/8/2005 7:26 am ET by JPSzcz
>> The H-clips I was referring to are Seismic and Hurricane Ties. << - right. I knew that you meant hurricane ties.
Project looks good!
Let us know how you feel about the 2nd floor performance.
Edited 11/8/2005 7:39 am ET by Matt
Reading the fine print on the Simpson web site, the type "B" is for use with trusses. The truss just sits there in one piece, it doesn't want to slide off and down like a rafter.
A 12 in 12 is the easiest bird's mouth to make, because the angle (45 degrees) and depth are the same for both cuts. You can clamp a bunch of rafters together, tack down one by guides, and gang cut them.
-- J.S.
The hurricane clips will support the load they are rated at.
They do a fine job without bird's mouths.
"The hurricane clips will support the load they are rated at.""They do a fine job without bird's mouths."The point I'm trying to make is that it's not the load that they can support it's the difficulty with the installation of of the clips and the rafter. There's to many steps involved with struggling to hold the rafter exactly in place and then nail them into the clips.Why not cut a birdsmouth for ease of installation since he's never cut a roof before why should this guy struggle with installing rafters?What clips are you talking about anyway?Joe Carola
bs... they are designed to resist uplift... they won't stop deflection and spread
they are designed to do a specific job ... not to replace a seat cut / birdsmouth Mike Smith Rhode Island : Design / Build / Repair / Restore
Perhaps you should read the manufacturer's literature and directions and review the National Design Standard for Wood Construction.
Yeah, sure!
Have you ever built anything?
is it still standing?
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If you want to eliminate a birds mouth, you would have to use vpa.
http://strongtie.com/products/connectors/VPA.html
"The hurricane clips will support the load they are rated at."
This is true, however, the load they are rated at is an uplift, as Mike has pointed out.
Those VPA's are the ones that I was talking about in this thread and another thread and trying to explain that there's no time saving and to many steps involved just to nail a rafter in without cutting a simple birdsmouth.http://forums.taunton.com/tp-breaktime/messages?msg=64346.3Joe Carola
were you planning to place the "B" clip on the outside of the wall. In most cases the ties get placed on the inside. in which case without a birdsmouth the tie will not be able to be attatched to the rafter as the the underside of the rafter would be aligned with the outside of wall as opposed to the inside of the wall. So I don't see how these ties could be designated for rafters without birdsmouth. unless of course they are meant for outside of wall placement. which I have never seen But I could be wrong. I beleive it was mentioned that they are meant for trusses which makes more sense.