Replies

1. 
   Guest_ | Aug 24, 2000 04:55am | #1

   *
   Rob,

   Buy a Speed Square at your local tool store.

   Read the book. It has all you need.

   Ed. Williams

1. 
   Guest_ | Aug 25, 2000 02:23am | #2

   *Yep. I agree. Go to Home Depot or Lowes or whatever, buy a Swanson's Speed Square, with the little blue book, and read it. It'll come to you, like a lightbulb, how this works. If it doesn't, come on back...

1. 
   Guest_ | Aug 25, 2000 07:13am | #3

   *do it like we all do, just keep cuttin' 'er till she fits.jim

1. 
   Guest_ | Aug 26, 2000 12:18am | #4

   *Rob,

   What size rafters are you using?

   View Image © 1999-2000"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle

2. 
   Rob_Sheffield | Aug 27, 2000 05:12pm | #5

   *
   Hi Joe,

   I am using 2 x 6's. The deck 15' wide x 10' deep.

3. 
   Guest_ | Aug 28, 2000 03:07am | #6

   *

   Rob,

   Here are some methods you can try. I believe these are by far the simplest way to figure how to cut the birds-mouth and plumb cut for any rafter.

   You will need a tape measure, string line, framing square and a bevel square.

   Whatever the width of your rafter stock is subtract 1-1/2" from it and cut a block that wide. i.e. if yours is 5-1/2" (2x6) cut the block 4".

   Place this block on the rafter plate even with the outside edge. Tack it there.

   
   

   Now tack a string from the ridge to the outside edge of the block.

   Now using the bevel square you can determine the plumb cut angle. Place the bevel body against the ridge and align the beam with the string.

   Also measuring from the two points were the string meets the ridge and the block will give you the length of the rafter.

   Now crown the rafter stock. Put the crown side away from you. Now lay your rafter out the following way. Make one mark at the front of the raft, using the bevel scribe the ridge cut. Measure down the rafter the lenght you measured and make a mark there. Scribe that line, this is the plumb cut line of the birds mouth.

   From the top of the bird-mouth plumb cut line measure down the same 4" you used for the block and make a mark. From that mark draw a line square to the plumb mark in the direction of the ridge cut.

   Now cut the shaded areas and your done.

   If you want to read some more on roof framing try this.

   Good luck.

   View Image

   © 1999-2000

   "The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it."

   Aristotle

1. 
   Guest_ | Aug 28, 2000 08:54pm | #7

   *Nicely done Joe. Quick, clear and easy to understand.Rob, after you've checked the fit of Joe's rafter, bring it back down, tack two chunks of 1/2 or 3/4 to the top of the rafter. One near the house end and one directly above the birdsmouth. The chunks should be perpendicular to the run of the rafter and hang off each side. Now you have the pattern for the rest. Crown the rest of the 2x6's the same way you did the first. Place the pattern on top and pull it till the chunks are tight against the top of the one you want to mark. This will register the important points from one rafter to the next. Mark it and cut it. If the deck line is running true to the wall, they'll all fit like the first. Best of luck.

1. 
   Guest_ | Aug 28, 2000 10:19pm | #8

   *calvin,

   Thanks. I'd hate to admit it , but I've cut more roofs that way then any other way. And as you know I can cut them a few ways :-}

   View Image © 1999-2000"By the time a man realizes that maybe his father was right, he usually has a son who thinks he's wrong." Charles Wadsworth

1. 
   Guest_ | Aug 29, 2000 12:32am | #9

   *Mr. Fusco:A very succinct and useful way of doing the job. It even eliminates the risk of mathematical errors.

1. 
   Guest_ | Aug 29, 2000 03:30am | #10

   *Although I've never tried this, it might work here. First, make sure your wall is straight at the top plate, parallel to the house (and therfore the ridge) and plumb.Second, eyeball the plumb cut at the ridge (after crowning!)Third, get a helperFourth, raise the rafter and slap it to the endgrain side of the ridge and top plate. Put it where you want it. Fifth, scribe it.Leave the line when cutting.Whether or not you can make this work at the ridge is your call. It can also be risky to trust that ALL the rafters will be the same length, even if you thought you did a perfect job straightening the wall.

2. 
   Guest_ | Aug 30, 2000 04:17am | #11

   *How high can you go with your rafters? What is the roof covering material?....I belive shingles must be 3/12 min. The angles are easy to determine but be sure you have enough pitch for the roofing material you plan to use...I concur use the speed square and book with what you plan to do.....either that or use a framing square....hold one side on 12 and the other on the pitch you want and you have the angle for common rafters....one angle is frontside and one is the backside....you will figure out which side is right after a time or two.........a hint.....the shorter line drawn is the one for common rafters....the longer is the backside....

3. 
   Guest_ | Aug 30, 2000 04:28am | #12

   *TomI think it might work assuming the new rafters terminate at the same point the wall makes a corner. If not he will have trouble marking the top cut at the ridge. Of course he could temporarily let the ridge and plates " run wild" beyond the corner or termination point. I guess the simplest way would be to buy a cheap angle finder and lay a straight edge across both and read the angle. If a birdsmouth is used then the ridge would have to be raised the plumb distance from the heel cut to the top of the rafter.

4. 
   Guest_ | Aug 30, 2000 04:34am | #14

   *well, i think joe's method is the closest to idiot proof i've ever seen..and it's especially good for additions because it is often difficult to get the correct rise and run due to obstacles...if the wall and the ridge are parallel, and both are level, it's foolproof.

4. 
   Rob_Sheffield | Aug 30, 2000 04:34am | #13

   *
   Are there any SIMPLE methods around to figure out the angles required for cutting rafters to fit against the exterior wall of my house. I'm planning to build a roof over my deck.