# Joining 4 2x4s at one point



## One (May 29, 2013)

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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## Dominick (May 2, 2011)

Go check out chain carver Steve's gazebo. 
You may find your answer here. 
http://www.woodworkingtalk.com/f13/gazebo-build-51486/


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## bzguy (Jul 11, 2011)

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


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## One (May 29, 2013)

bzguy said:


> 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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## woodnthings (Jan 24, 2009)

*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 (Jul 11, 2011)

One said:


> 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.
> 
> ...


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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## afx (Feb 5, 2010)

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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## One (May 29, 2013)

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 (Feb 5, 2010)

One said:


> AFX you freaking rock!
> 
> Thank you so much for the angles and drawings.
> 
> ...


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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## One (May 29, 2013)

afx said:


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



Yikes...

:hang:


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## woodnthings (Jan 24, 2009)

*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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## FrankC (Aug 24, 2012)

One said:


> AFX you freaking rock!
> 
> Thank you so much for the angles and drawings.
> 
> ...


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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## afx (Feb 5, 2010)

FrankC said:


> 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.


I would assume that the gazeebo is 8 feet by 8 feet.

I still personally think that 4 support's isn't enough.


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## afx (Feb 5, 2010)

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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## woodnthings (Jan 24, 2009)

*it's a cube, not a hexagon*



afx said:


> 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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## afx (Feb 5, 2010)

woodnthings said:


> afx said:
> 
> 
> > 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)
> ...


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## One (May 29, 2013)

afx said:


> woodnthings said:
> 
> 
> > I'm assuming that he is capable of subtracting 2 from 6
> ...


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## afx (Feb 5, 2010)

One said:


> afx said:
> 
> 
> > There are other numbers past 1?!
> ...


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## woodnthings (Jan 24, 2009)

*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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## afx (Feb 5, 2010)

woodnthings said:


> 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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## One (May 29, 2013)

FrankC said:


> 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.




Alright, you guys got to try the sh!t I was smoking last night when I was drawing this out... heh.
So I built the roof structure. Dragged it and slapped it onto my 8' cube. Started fastening it to the sides. And boom! It hit me! FrankC was right to be confused with my drawing because I DEFINITELY SHOULD OF HAVE MOUNTED RAFTERS DIAGONALLY. 

It looks so freaking funny you guys will have enough comedy material on me for ages.

Back to the drawing board I go.

:chef:


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## One (May 29, 2013)

afx said:


> 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?



afx, I can't have the overhang because the canvas structure I'm draping over the frame does not have the room for one. You have my permission to call it a shed!:laughing:


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## One (May 29, 2013)

One said:


> Yikes...
> 
> :hang:




btw afx, you called it. I was pretty much half way done!


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## One (May 29, 2013)

OK, so generally I do not post photos of my massive failures, but as you guys have been such good sports I will give you guys a rolling laugh.


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## One (May 29, 2013)

You guys will notice the strange diagonal 2x4's at the top of my cube. Those came handy when the bottoms of my "triangles" weren't quite on top of the cube.


A botched job to boot. I'll give it another try over the weekend -- this time with a much, much, better plan, I hope.


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## One (May 29, 2013)

woodnthings said:


> 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:



After closely studying your drawing, I decided that it is probably my best bet at the moment. 

Originally I was hoping not to use so much wood mainly to keep the inside as open as possible. The "roof" structure that I've built, although probably quite laughable, is pretty darn solid. I really don't care it it survives a hurricane. We don't have many hurricanes here and so I was hoping to give a good-enough method a try (I'm usually a perfectionist). If a hurricane comes and destroys my roof -- I'll have a bonfire and rebuild it a bit better a week later.


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## woodnthings (Jan 24, 2009)

*ok, dude you R so lost....*



One said:


> OK, so generally I do not post photos of my massive failures, but as you guys have been such good sports I will give you guys a rolling laugh.


Hopefully there is some more lumber in that black box at the lower left side of the photo montage.... :yes:

You can't use a 2 x 4 on the flat without any support under it. :no:
You have no diagonal braces to prevent racking. :no:
I would remove the chair from underneath and relocate it about 10 ft away... 
You need to put a plumb level on all 4 verticals then brace them when you get it plumb. Diagonal braces in the upper corners at a minimum. This thing will fold like a damp cardboard box that been out in the rain. 

Where r you located. We'll be right over....... :yes:


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## One (May 29, 2013)

woodnthings said:


> Hopefully there is some more lumber in that black box at the lower left side of the photo montage.... :yes:
> 
> You can't use a 2 x 4 on the flat without any support under it. :no:
> You have no diagonal braces to prevent racking. :no:
> ...



I'm in Theiveland, just down the way from you!


I know I need braces! :tooth: Don't rub it in :furious:.

:laughing::laughing::laughing: 

I have to make sure the structure is movable by two people because it is getting relocated. On the other hand I had five people swinging from all sides of the cube couple of days ago to "test" for rigidity. That's what? ~800lb of a dynamic load? It held! That cube is pretty darn solid, but you are right, I will brace it after I move it to it's permanent location.



Sir, I shall do better for my next try!


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## afx (Feb 5, 2010)

Woofabear,

I mean it isn't too bad....But.....You just need to get it in place and double up on everything. I'm sorry but I'm calling shenanigans on your friends swinging on the sides because a 2x4 isn't going to hold that much weight lying down.

I'm having trouble trying to think up solutions because of the canvas you want to lay over the top of it. I kind of think you're wasting $50 in wood trying to save $50 in wood.

My best suggestion would be to double up on everything with some wood glue and nails and put some corner supports everywhere to help support the roof. It wont take a hurricane to get that thing airborne especially when you're about to attach a sail to it.

These are the projects we all learn from. I cant tell you how many projects I've thought I planned for in every way but in the end was disappointed and embarrassed to use it.


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## One (May 29, 2013)

afx said:


> Woofabear,
> 
> I mean it isn't too bad....But.....You just need to get it in place and double up on everything. I'm sorry but I'm calling shenanigans on your friends swinging on the sides because a 2x4 isn't going to hold that much weight lying down.



afx :thumbdown: for doubting me! Now I have to get everyone back together and back on it for a photo op! Btw, it's hard to notice from the photos, but there are two 2x4s making up each corner post of the cube.



Not sure that you mean about wasting $50 in wood trying to save $50 in wood -- other to call my build pointless. I guess it is pointless really... :shifty:


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## afx (Feb 5, 2010)

One said:


> afx :thumbdown: for doubting me! Now I have to get everyone back together and back on it for a photo op! Btw, it's hard to notice from the photos, but there are two 2x4s making up each corner post of the cube.
> 
> 
> 
> Not sure that you mean about wasting $50 in wood trying to save $50 in wood -- other to call my build pointless. I guess it is pointless really... :shifty:


Hey hey now, I wasn't calling your build pointless. 

I'll give you an example of what I meant. When I first started woodworking, I made a coffee table, the top was made out of pine boards jointed and glued together. When I finished the top I noticed I only had enough wood to make a top that was 30 inches wide instead of 32, I hadn't taken into account how much material jointing would remove. Instead of going to buy another plank of wood I just shrunk everything else down to 30 inches. As it turned out, I wasn't that good at shrinking stuff because everything was off and the table looked like crap and I scrapped it. In the end, to save $5 on a plank of wood, I ended up wasting $50 in wood making a table that I ended up scrapping.

On the 2x4 corners comment, it looks like you butt jointed them together which isn't going to lend any strength at all. You need to glue them face to face and double the thickness of the 2x4.


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## One (May 29, 2013)

I kind of lost interest in the build for a while...

I did not like the fact that I had to put a heavy roof on the 'zebo. This will make it a chore to move around. Who moves their gazebos around? I do! So there. Like it or not, I have to make the 'zebo light and relatively safe. How to do that? Well, I'll give you guys a clue: what is a 5gal bucket filled with concrete to a roof of a gazebo? 



Pictures are on the way!













afx said:


> Hey hey now, I wasn't calling your build pointless.
> 
> I'll give you an example of what I meant. When I first started woodworking, I made a coffee table, the top was made out of pine boards jointed and glued together. When I finished the top I noticed I only had enough wood to make a top that was 30 inches wide instead of 32, I hadn't taken into account how much material jointing would remove. Instead of going to buy another plank of wood I just shrunk everything else down to 30 inches. As it turned out, I wasn't that good at shrinking stuff because everything was off and the table looked like crap and I scrapped it. In the end, to save $5 on a plank of wood, I ended up wasting $50 in wood making a table that I ended up scrapping.
> 
> On the 2x4 corners comment, it looks like you butt jointed them together which isn't going to lend any strength at all. You need to glue them face to face and double the thickness of the 2x4.


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## Tman1 (Jan 14, 2013)

I have to make a few comments on your structure. 

1 - 2x4's attached at a 90 degree angle actually make a better structural corner post than gluing them up into almost a 4x4. 

2 - The key to prevent racking is triangles. More importantly, it is triangles in the fasteners. The bigger the triangle, the stronger the protection against racking. If the 2x4's are attached using a triangle pattern with the fasteners, it will tend to resist racking. But, the stress on the fasteners may be pretty high and over time they could loosen. The good news is that by joining the corner posts at a 90 degree angle, you made some bigger triangles. Based on what you are after, if it doesn't rack now, I would leave it alone. If it starts to rack later, I would go back and add some short 1x4 braces to reinforce the structure. They should be pretty light so, if you wanted to, you could do it now. The key on the 1x4s is to use lots of screws so that there isn't opportunity to loosen up over time. 

3 - As far as the roof structure goes, I think you did a good job, you just need to go from the corners instead of the sides. Again, on the bracing, you should be able to use 1x4s instead of 2x4s, but use lots of screws. 

That's my 2 cents.


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## One (May 29, 2013)

I finally had time to finish this project! I used woodnthings' measurements and my style of brace construction at the top. It's basically just like my old one. I corrected the mistake by making the roof from the corner posts. I am going to install a hammock and see if it can hold couple of people. I'll shoot some photos if everything will work out well.


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