Replies

1. 
   stossel1 | Jul 23, 2003 06:57am | #1

   Heres how I do Gable walls, maybe it will help you out.

   1 Lay out your bottom plate and tack it down.

   2 Pull 42" up from the bottom of your bottom plate and make a mark. This is the height of your side wall. Tack a 2x the same width as your side wall to this mark.

   3 Calculate your rafter length. Cut both your rafters and lay them so they are resting on your block  {side wall height}  and meeting in the middle {ridgeline}. If you did everything right it should fit together like a puzzle.

   4Now you have a pattern, remove the blocks that you used to establish top of wall and frame your wall to the bottom of your rafters. You can easily figure out your ridge pocket as well.

   5 Sheath the whole mess and lift it with the same crane you will use on your ridge. If you have room you can frame both your gable walls , then have the crane lift them both and set the ridge at the same time. Make sure your bottom plates are nailed down securely.    good luck

2. 
   sweetwater | Jul 23, 2003 07:06am | #2

   I would draw the wall exactly on the floor, snapping lines for top of wall and stud heights (parallel) and include all windows, doors, beam pockets, whatever. I might leave out the ridgepost (6x6, etc) and stand that alone with column cap after the wall is up, plumbed and braced.

   With that much weight, I'd split the wall in half at that pocket. I wouldn't leave a gap for the rafters - just double-check and go for it. You will need wall jacks or a crane to lift each sheathed half as it is; don't try it without one of those, it's just too top-heavy to control.

   One caution: the accuracy of the wall framing will only be as good as your math and the levelness of the floor. If you feel the floor is out of level, then I'd just stand the wall without shearwall, plumb and line before shearing later.

   Good luck, have fun!

   Don

1. 
   dieselpig | Jul 23, 2003 04:14pm | #3

   Any of the ways already mentioned will work.  Coupla pointers (I do this every coupla weeks).  First, and it doesn't matter whether you use wall jacks or a crane, use steel bands that come with your lumber to secure the bottom plate to the deck.  On a 26' wall I'd probably use at least three.  Let em about 16" into the room and nail em through the decking preferably into a joist, thread under the top plate, up and around it and back into a stud or jack/king stud combo.  Hand nail the straps, for safety (ricochets) and also so the gun nails don't blow through weakening the straps.

   Pole jacks or wall jacks can be rented in lots of places if you don't think you'll use them much, however IMHO they are an awesome investment.  They also have a good resale value and are easy to get rid of if you have to buy them and don't wanna keep them.  I'd rather use jacks than a crane or even my lull any day.  The jacks offer plenty of control and you can raise the gables at what ever rate you are comfortable with.  This lets you really keep an eye on things while the wall goes up, a lot can happen while raising big heavy gables.  It's much easier to just stop pumping if something looks out of whack, rather than trying to wave off a crane operator who is probably focused more on the wall than you.

   One more thing, I also use "strong backs" or half backers (usually about 12').   Two or three of them nailed  through the exterior sheathing into framing can really stiffen up a gable for raising.  It keeps the wall from getting all distorted and "whipped" while raising it.

   Sorry for the long post, but raising gables is no-joke.  It should be done efficiently, and the more thought you put into the forces involved, the smoother it should go.  Every safety precaution available to you should be taken.

1. 
   urbanmr | Jul 23, 2003 06:40pm | #4

   Hey Dieselpig-

   I'm an interior guy who wants to start doing mudsill up kind of work, so I'm interested in your posting but have no idea what you're talking about--the metal straps go where?  I've heard of using them as a kind of hinge at the sole plate, but I didn't understand about threading under the top plate, etc.  Also, the strongbacks--are they just 2xs that sandwich the framing from the inside?  If so, how do you slip them under the wall?

   If you have a minute to explain you'd make me a happy fledgling framer.

   thanks,

   Michael

1. 
   dieselpig | Jul 23, 2003 10:19pm | #5

   Michael,

      Sorry one major typo on my part....the steel bands are threaded under the BOTTOM plate of the wall, not the top plate as I wrote!   OOOPS.   Picture your wall all framed and laying on the deck, prior to sheething.  Take about a 2' piece of the steel banding that wraps your bundles of framing lumber.  Pick the thickest piece you can find....not all are equal.  Thread it between your bottom plate and subfloor.   Nail the part of the band inside the frame to the floor (preferably into a joist and not just subfloor!).   Bend the other end up and then wrap it around the bottom plate and back up the wall...nail it down as well.   What happens when you stand that big wall up is that the bottom plate wants to shoot right off the frame rather than just roll up....like footing an extension ladder against something while raising it.  I hope this is a clearer picture.

   As far a strong back or half backer goes... just take a couple of 12' or so 2x4's and nail em together edge to edge to make an L like half of a partition channel or pocket of halfbacker or whatever you call em where you're from.  These get nailed right to the face of the gable, through the sheathing and into the framing.  Up here in MA it is common practice to just build a regular wall same height as the rest of the floor and then frame the gable on top of that...and just sheathe the whole dang thing.  We do this pretty much anywhere that there isn't a vaulted or cathedral cieling, in which case we balloon frame.  This hinge point created by the top plate of the wall and the gable on top of it is a major stress point while raising gables.  The strongback I described above span this joint and helps  a great deal to stiffen the gable during the lift, no matter how it was framed.  Wall jacks (or just about any other method of raising a gable) can cause the wall to have a "whip" in it where the connection to the raising device is made.  Strongbacks help the wall get raised evenly.

   Whew....sorry so long winded.  That's about as clear as I can describe it.  I'd love to show you instead sometime if you're ever in MA!!    ;)

1. 
   urbanmr | Jul 24, 2003 01:16am | #6

   Thank you so much.  That's crystal clear now.  What part of MA do you build in?  I'm actually going to be building my first house (start to finish) in Wellfleet--even though I live in NYC.  I'd happily hire myself out for laborer's wages to learn some of this stuff first hand! Let me know if you're ever hiring.

   thanks again.

   Michael

3. 
   MikeCallahan | Jul 24, 2003 06:01am | #7

   12/12 roofs are very pleasing to the eye and also easy to build. Since the total rise and run are equal then figuring is easy too. For a 26' wall the total rise would be 13' or half the total run. If you put that on a 42" wall then the total height should be 198" and not 192" as you stated in your post. If you build to a height of 192" then your pitch will be 43.8 degrees and not a 45. Not good. Engineers frown on a 6" birds mouth and I don't know what your notch detail is so maybe your original height of 192 was allowing for a six inch birds mouth. Actually on second thought with 1/2" shear on the outside then 192" is right on.

   The diagonals are proportional to the square root of 2 so multiply 13' or 156" times 1.41 and your top plate length is 220.61". Shorten the top plate by half the width of your glulam (2.75" x 1.41 = 3.88") Frame the gable walls inside the side walls so your top plate should be shortened another 5.5"x 1.41 = 7.75" assuming your side walls are 2x6. Your top plates will be 209" long to short point.

   Snap lines on the floor. Build the wall. Gable studs will grow the same as the layout spacing so if you have 16" centers then each stud will grow exactly 16" in relation to the shorter one next to it. The first stud against the side wall will have to shorten so the double top plate will line up with the inside edge of the side wall. In your case then, 3" of top plate would be 4.24" high,(3 x 1.41) so your first gable stud would shorten 1.25" at the short point in relation to the side wall stud. If your side wall stud is 37.5" then your first gable stud should be 37.5 - 1.25 = 36.25" at the short point. Find the length of your longest stud at your beam pocket by adding the length of the short stud to the total run which is 156 -(2.75) -(5.5) + 36.25 = 184" to the long point.

   Nail the hinge straps described in a prior post so the bottom plate is lined up exactly on the bottom plate layout line. Gable walls are hard to reach so I like to at least shear the wall before it goes up. Run your shear past the top plate to provide nailing into your rafters.

   I like to overlap the rafters on a beam instead of hanging them. You have enough head room to allow it. You will probably have to add web stiffeners to the top of the rafters. If the rafters overlap then you will have to drop the beam pocket. The beam should drop half the width of the beam plus the height of the beam. So the rafters don't bear on a point you will have to rip blocks at a 45 and build up the top of the beam Here in earthquake country, having shim space on top of a gable wall is a no no. The rafter should fully bear on the wall so you can attach all those A-35s that are specced. They don't do anything if your shear continues above the top plate and nails to the rafters but duh, I'm no engineer.

   I also like to use the wall jacks. Be sure to place the stop on the wall jacks at the right spot so you dont jack the wall over the edge. The stop directions are on a label on the Proctor wall jacks. You will have to leave a notch in the overlapping shear to accomadate the wall jack.

   Whew... Did you get all that? Sorry I did all the fun stuff(calculations). Now go build that wall. Good luck.

   We may be slow, But we're expensive.