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Discussion Starter · #1 ·
I'm building a gazebo. I am pretty much done except for the roof. I would like to join four 2x4s at one point. I have a really nice miter saw with all sorts of angles on it. I haven't used it for much though so I am unfamiliar with all of the angles. I know what I am asking is pretty complex, and I am probably not giving you guys enough information, but that's because I have no idea where to start and what to measure. My gazebo is more or less a cube made out of 8 foot 2x4s. I made it to fit the canvas structure that I had from a store bought gazebo that fell apart because it used cheap thin metal poles for the frame. The roof is not flat and it needs four supports that angle upwards from the cube (main gazebo structure) to provide the steeple.


Let me know what I have to measure and if pictures will help.


Thank you so much!

:smile:
 

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Discussion Starter · #4 ·
This link is for figuring compound angles for a rectangular pyramid.
Your pyramid is square, punch in the dimensions, 8' X 8' X ?

http://jansson.us/jcompound.html#pyramid

This is pretty helpful!

The thing is that it doesn't give me the length of the 2x4s and I think it also assumes that I will be dealing with sheets rather than just a carcass of 2x4s. Also what would be the angle at the cube? this just calculates the top joint angles.

How to measure the length of the 2x4s?


Thanks for all your help!

:smile:
 

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where's my table saw?
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use trigonmetery

or the Pythagorean Theory. a2 +b2 = c2
The center of the square is 1/2 the diameter.
Determine how high you want the peak off the side wall....slope of the roof.
a2 is 1/2 the diameter, b2 is the height of the roof... then solve for c2 which is the length of the roof rafters. You can extend them beyond the walls if you like that style. You don't need complicvated angles on the ends at the top. Just attach a square block in the center and use metal fastener hangers or toe screws at an angle You can put a 4 x 4 down to the ground to hold it. You can use clamps to hold the rafters in place while you attach them.

2 means squared
 

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bzguy
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This is pretty helpful!

The thing is that it doesn't give me the length of the 2x4s and I think it also assumes that I will be dealing with sheets rather than just a carcass of 2x4s. Also what would be the angle at the cube? this just calculates the top joint angles.

How to measure the length of the 2x4s?


Thanks for all your help!

:smile:
Your canvass structure determines the height of the"pyramid" at the top of the square sides. The 1&5/8th's edge of the 2 X 4's becomes the "face" of the pyramid sides/sheets.
 

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Ughh, damn these eyes! I thought the entire time I read this thread that you were wanting to JOINT 2x4's I was thinking "how come no one has told him to use a jointer?"

My answer to your REAL question would be that you're wanting to do more work than you need to, say you are using 6 supports for the roof at a 22 degree angle, take a 4x4, cut 7 inches off of it and then make it a hexagon by cutting 6-60 degree cuts. Now all you have to do is cut the 2x4's at the proper angle which I think is 112 (or 68 on your miter saw) and nail all them into the 4x4 hexason you just cut out, then BAM you're done.

IF you REALLY want to do the math and draw it out. Essentially you would take the angle of the 2x4, say 22 again, cut a 112 degree cut (68 on the saw) and then cut a 60 degree angle on it so the 6 2x4's would join to make a 360 degree circle. That is REALLY complicated though.

On a final note, I made my example with 6 supports because I think 4 is too few and wont lend enough support to the structure.


Here is a pic I drew up to hopefully illustrate the harder way.




And here is a pic of the easier way.


 

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Discussion Starter · #8 · (Edited)
AFX you freaking rock!

Thank you so much for the angles and drawings.

I had a wee bit of time to think about the problem myself and I also came up with a possible solution that follows the venerable KISS method:

I want to implement a variant of this rafter/collar tie system:


The above system has multiple "triangles" parallel to each other where I basically will construct two "triangles" placed perpendicular to each other and call it a day: that will create the effect that I am looking for (four 2x4s joined together in one spot).




Using this calculator, http://www.csgnetwork.com/righttricalc.html , I calculated that if the height of my right "triangle" is 3' and it has a 4' base (8'/2) then I will have to cut the angles in this manner:








What do you guys think?


:)
 

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AFX you freaking rock!

Thank you so much for the angles and drawings.

I had a wee bit of time to think about the problem myself and I also came up with a possible solution that follows the venerable KISS method:

I want to implement a variant of this rafter/collar tie system:


The above system has multiple "triangles" parallel to each other where I basically will construct two "triangles" placed perpendicular to each other and call it a day: that will create the effect that I am looking for (four 2x4s joined together in one spot).




Using this calculator, http://www.csgnetwork.com/righttricalc.html , I calculated that if the height of my right "triangle" is 3' and it has a 4' base (8'/2) then I will have to cut the angles in this manner:








What do you guys think?


:)
I think you're going to get half way through building it And think "what the hell was I thinking?"

You're good to go any way you chose. I'm not understanding your rafter method but that doesn't mean it won't work. Good luck and keep us posted with pictures!
 

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where's my table saw?
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build the trusses on the ground first

Lay out the length of the side, .... 8ft, find the midpoint, ...4 ft, set a vertical to approximate the height and then locate your rafters, the length needed to for your canopy to fit. You adjust the vertical to suit the peak of the canopy and the rafters will adjust themselves automatically if there is just one nail on the vertical to pivot on. Let them run "long" and then cut them after it all fits.

Then attach the collar tie to hold it together. Set the first truss on the top plate then allow the second truss to slip under the first one with a gap for the thickness ...1 1/2" at the top. Vou don't need a fancy block if your are just using 4 rafters. Once you get the 4 midpoints and want to do the corners you can just cut them to fit ....no math needed for the lengths.

I would not attempt to build this "in the air" from a ladder.... except for the corner rafters.
 

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AFX you freaking rock!

Thank you so much for the angles and drawings.

I had a wee bit of time to think about the problem myself and I also came up with a possible solution that follows the venerable KISS method:

I want to implement a variant of this rafter/collar tie system:


The above system has multiple "triangles" parallel to each other where I basically will construct two "triangles" placed perpendicular to each other and call it a day: that will create the effect that I am looking for (four 2x4s joined together in one spot).

Using this calculator, http://www.csgnetwork.com/righttricalc.html , I calculated that if the height of my right "triangle" is 3' and it has a 4' base (8'/2) then I will have to cut the angles in this manner:








What do you guys think?


:)
Won't the rafters have to run from corner to corner, if so your calculations will have to be based on the length of the diagonal not one of the sides.
 

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alright broskie, here's what I want you to do, use my first suggestion with the hexagon and toenail the 4 supports into it, then toenail 2 additional supports between each beam for added support, notch out the joist to inlay with the top of the gazeebo and secure it with hurricane clips (find them at home depot)

Here is another drawing to illustrate. The first is the top itself, the second is the rafter layout.



 

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it's a cube, not a hexagon

alright broskie, here's what I want you to do, use my first suggestion with the hexagon and toenail the 4 supports into it, then toenail 2 additional supports between each beam for added support, notch out the joist to inlay with the top of the gazeebo and secure it with hurricane clips (find them at home depot)

Here is another drawing to illustrate. The first is the top itself, the second is the rafter layout. Pardon the picture size, I'm at work and dont have my usual editing programs

His drawing:

 

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alright broskie, here's what I want you to do, use my first suggestion with the hexagon and toenail the 4 supports into it, then toenail 2 additional supports between each beam for added support, notch out the joist to inlay with the top of the gazeebo and secure it with hurricane clips (find them at home depot)

Here is another drawing to illustrate. The first is the top itself, the second is the rafter layout. Pardon the picture size, I'm at work and dont have my usual editing programs

His drawing:

I'm assuming that he is capable of subtracting 2 from 6
 

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Discussion Starter · #17 ·
I'm assuming that he is capable of subtracting 2 from 6

There are other numbers past 1?!
Holy buttermilk pancakes!!!

Why haz i not bin informed?!
:furious::censored::furious:


Seriously though, all your guys' suggestions have been very helpful. I am going to mix and match and take pictures of the Frankenstein!


Give me another couple of hours, eh?

:thumbsup:
 

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There are other numbers past 1?!
Holy buttermilk pancakes!!!

Why haz i not bin informed?!
:furious::censored::furious:


Seriously though, all your guys' suggestions have been very helpful. I am going to mix and match and take pictures of the Frankenstein!


Give me another couple of hours, eh?

:thumbsup:
Hah, sounds like a plan!

Some of my best work comes from mixing and matching different ideas/styles.

Definitely take pictures!
 

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where's my table saw?
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here's what I got for ya

The hip rafters, to the corners, will be longer than the jacks to the center. 7.13 ft by my calculations. The base length to the corner is 5.65 ft. the height is 3 ft the angle at the top is 36.8 degrees and at the bottom it's 53.1 degrees.:smile:
 

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The hip rafters, to the corners, will be longer than the jacks to the center. 7.13 ft by my calculations. The base length to the corner is 5.65 ft. the height is 3 ft the angle at the top is36,8 degrees and the b ottom is53.1 degrees.:smile:
The only 2 things I would change about that is 1. you want some sort of overhang for a gazebo right? otherwise it's just a shed with no sides :laughing:

Secondly, It looks like he want's the rafters to intersect with the middle of the 2x4's, not the corners.

Am I misunderstanding what you were trying to say?
 
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