How do i determine an angle and measurements to layout cut lines?

[Bill Furnett]

I guess i should know this kind of thing, but I just don't and yet i'm at a point where i simply must learn as this "Technigue" will come into play more and more in the near future of my build.

That said, how do i determine (which tool) the angle of my ceiling in an A-frame attic where the ceiling height decreases as you go deeper into the room? In addition to figuring out the angle I need to be able to get the proper measurements so i can layout cut lines on a door that will fit under this angled ceiling. Hopefully my two simple paint drawings can help better explain.

Thanks

 

[tarnationsauce2]

An angle finder will help a lot.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=1028

 

[Dani Pace]

Yep the tool for the job is an angle finder. You can get one from almost any hardware/ building supply store.

 

[Bill Furnett]

Hey thanks guys

That looks pretty straight forward and also rather inexpensive.
I suppose once i obtain such device i'll do a few practice cuts on scrap,
then go for the gold.

 

[RICK FITZPATRICK]

Heres another.
http://www.roofgenius.com/roofangle.htm

And here is another thought. Roof pitches are based on a common ratio fomula that uses a right triangle with specific integers on each leg of the right angle.

The horizontal leg(parallel with the floor is the run. The vertical leg is the rise.

Roof pitchs are usually specified in x"rise for every 12"run. As an example, a5/12 pitch is 5"rise for every 12" run. IF, you know what the pitch is, most angle problems can be extrapolated from the roof pitch Understanding a few conventional roof construction/math concepts will aid in the use of a typical framing square to determine the solution to many problems that occur in layouts of this nature.

http://www.josephfusco.org/Articles/Roof_Cutting/raftercutting.htm


If you don't know the pitch, a simple measurment setup can help. Use a level and a tape measure to determine roof pitch. Measure off 12" from one end of a level and make a mark. Place that end of the level up against the bottom edge of a rafter and level the level. Meaure the distance from the 12" mark up to the bottom edge of the rafter using an imaginary plum line. If it measures 4", your roof has a 4

Then either extrapolate the desired angle/distance etc, using math, or look up the angle in roof pitch calculation tables, or tranlate points on the floor using a square, level, plumb line and a tape.

Personally, I use it all, but mostly I use CAD to TELL me what I need to know. Like this Monitor Soffit framing plan.

It must have worked.

fitZ

 

[Bill Furnett]

Ahhh that little attached image makes a lot of sense. Thanks Rick
I'll be sure to read the linked article, not that i'll understand it, but I'll try.

I haven't seen a pic from Fitzpatrick Castle in a few years. I believe I remember the console in it's CAD design stage. Sweet!
I love the sofit design for monitors, room shape alteration and possible corner trap framing all in one shot and without taking up any significant amount of floor space. So simple, so well designed.

-Love it-

 

[knightfly]

Yeah, but Rick where ya gonna find trapezoidal shaped 1-1/8 plywood??!? :=))

 

[MadAudio]

Hey thanks guys

That looks pretty straight forward and also rather inexpensive.
I suppose once i obtain such device i'll do a few practice cuts on scrap,
then go for the gold.

"Measure twice, cut once." I heard that somewhere.....

 

[c7sus]

A squared plus B squared equals C squared.

SOH CAH TOA

Sine= Opposite/ Hypoteneus

Cosine= Adjacent/ Hypoteneus

Tangent= Opposite/ Adjacent

 

[RICK FITZPATRICK]

Yeah, but Rick where ya gonna find trapezoidal shaped 1-1/8 plywood??!? :=))

Its in the garage. 11 ply POPLAR. Only 3/4" though.

And actually, if I wanted, about a mile from my house theres a CUSTOM plywood
shop. They'll make it up to 4" thick if you need it. Any species too....well, if they have the veneers

 

[knightfly]

Gonna start me a Trapezoidal Tree Farm on the extra 7 acres...

BTW, pix of the soffit framing's lookin' good; you might accidentally make some noise in there in a couple more years

 

[RICK FITZPATRICK]

BTW, pix of the soffit framing's lookin' good; you might accidentally make some noise in there in a couple more years

;Couple of years my ass I'm blastin as I type...baffles or no baffles...still gotta have some music in here. Actually, I put up a couple of old Altec consumer speakers...absolutely WIERD....heard every BAD thing I've ever read about From nulls, to peaks, to a 1" stereo sweet spot...move my head a half inch...yikes....pressure nulls that hurt my ears, yucky ear splitin mids, no lows, drifting highs...man gotta get these baffles up quick.