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johnsuch 10-12-2006 02:36 PM

rafters
 
Have no clue how to measure,cut,or how to do bird'smouth in rafters.Help:(

joasis 10-12-2006 06:29 PM

Use the framing square reversed from the rafter cut, at the point the rafter intersects the wall plate.

Double A 10-12-2006 06:52 PM

Try Joe's site. He explains it quite well.

http://www.josephfusco.org/Articles/...%20length%20CR

Not Sure 10-12-2006 10:09 PM

Quote:

Originally Posted by Double A (Post 20636)
Try Joe's site. He explains it quite well.

http://www.josephfusco.org/Articles/...%20length%20CR

I don't know a lot about rafters and such, but I found Joe's site very interesting. I'm going to bookmark it!

Joe Carola 10-13-2006 07:07 AM

Quote:

Originally Posted by johnsuch (Post 20617)
Have no clue how to measure,cut,or how to do bird'smouth in rafters.Help:(

1) What is the width of the building?

2) What size rafters?

3) What size ridge?

4) What size is the overhang?

5) What is the pitch?

6) What is the wall thickness, 2x4 or 2x6?

Are you using a framing square, speedsquare, calculator?

joasis 10-13-2006 07:58 AM

I typed up a lengthy discourse on doing this, before deciding I was making it really difficult. I probably learned how to do this when I was 13 or 14...my Grandfather beat me over the head with a framing square to see if anything would stick, I think. It is a lot easier to show someone then explain it.

A few years back, one of my guys was painting tools for identification purposes, and painted my framing square..:furious: .it was the very same one my Grandfather had bought new from Sears and Roebuck in the 1930's. I have it put away, waiting for the chance to get it to someone who can strip and restore it, no matter what it will cost. And if you wonder why it was in with the tools we use every day, well...I was showing one of the guys how to do hips and valleys, and I hate the new squares.:censored:

Joe Carola 10-15-2006 01:49 PM

Quote:

Originally Posted by joasis (Post 20682)
I typed up a lengthy discourse on doing this, before deciding I was making it really difficult. I probably learned how to do this when I was 13 or 14...my Grandfather beat me over the head with a framing square to see if anything would stick, I think. It is a lot easier to show someone then explain it.

A few years back, one of my guys was painting tools for identification purposes, and painted my framing square..:furious: .it was the very same one my Grandfather had bought new from Sears and Roebuck in the 1930's. I have it put away, waiting for the chance to get it to someone who can strip and restore it, no matter what it will cost. And if you wonder why it was in with the tools we use every day, well...I was showing one of the guys how to do hips and valleys, and I hate the new squares.:censored:


Joasis,

Cutting rafters was always way back when and still is my favorite part of framing. What do you use now to figure them out?

joasis 10-15-2006 02:23 PM

We do very little true roof framing, per say, since when I build the spec homes, we use engineered trusses. One the few occasions every year we have to frame a roof, I use the tables from a speed square book, or my drafting program will call out the lengths and angles of hips and jacks. I worked with a guy who cut the roof free, never even knew what the tables were on a framing square...and you would never know it from seeing his work.

Joe Carola 10-15-2006 04:49 PM

Quote:

Originally Posted by joasis (Post 20870)
I worked with a guy who cut the roof free, never even knew what the tables were on a framing square...and you would never know it from seeing his work.

Joasis,

What do you mean that he cut the roof free?

How did he figure out rafter lengths? If he didn't use the framing square,did he use a calculator, book, what? He had to use something.

joasis 10-15-2006 05:04 PM

He would set the hip or valley rafters, and then measure the length of the first jack rafter, and then run with it. I think he had done enough, he knew he would be angled correctly, and the difference between the full and jack was what he subtracted. What I mean above was cut a roof free hand....maybe not the best choice of words there.

Joe Carola 10-15-2006 05:26 PM

Quote:

Originally Posted by joasis (Post 20884)
He would set the hip or valley rafters, and then measure the length of the first jack rafter, and then run with it. I think he had done enough, he knew he would be angled correctly, and the difference between the full and jack was what he subtracted. What I mean above was cut a roof free hand....maybe not the best choice of words there.

Joasis,

What I'm getting at is, how would he figure the length of the common rafters? They have to be in first in order to set the hips. After he sets his commons then he measures his hips or just precuts them without measureing.

To get his common rafter length for any pitch, he has to have a reference to go by. Whether he's using the hypontenuse on the framing square table,or a Construction Master Calculator, Scientific Calculator or a Rafter Book.

Bonus 10-15-2006 06:53 PM

You can use a string, an angle gauge and a tape measure and never know the pitch of the roof.

Joe Carola 10-15-2006 07:13 PM

Quote:

Originally Posted by Bonus (Post 20893)
You can use a string, an angle gauge and a tape measure and never know the pitch of the roof.


Yes you can, on something that's existing. I'm talking new work.

Your given a pitch and you have to find the length of a rafter. So you need something to go by.

joasis 10-15-2006 07:34 PM

I know what you are asking now...duh.....he did the math with a pencil..you know, a/sq + b/sq = c/sq for the common run + tails I would guess...this has been a lot of years ago. Like 29 of them, when I was first learning framing...and he taught me a lot, but not a lot of what I use today.

Joe Carola 10-15-2006 07:45 PM

Quote:

Originally Posted by joasis (Post 20900)
I know what you are asking now...duh.....he did the math with a pencil..you know, a/sq + b/sq = c/sq for the common run + tails I would guess...this has been a lot of years ago. Like 29 of them, when I was first learning framing...and he taught me a lot, but not a lot of what I use today.

Joasis,

There you go, Pythagorean Theorem.

He's given a pitch and he would have to figure out what the rise was and then the rise/sq along with the run/sq and then he would get the hypotenuse /length of rafter.


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