Tucker08
01-30-2013, 10:15 AM
I like to build stuff. I am not much for math. Never have been.
I could not handle the thought of paying $250+ for a roof jack so I started working on an alternative. I was going to do a trash can jack, but ended up looking at a roof jack and saying "i can make that myself."
So, the hard part is the math...and a simple explanation of the math was hard to come by...that is what I needed. I am no expert, but I thought I would offer what I learned in a way that I hope is easy to understand.
Here goes:
I got a 5ft 12" stack with a 12" to 10" collar. I will run the 10 inch stack pipe up through the 12 inch one and will have the collar affixed to the stack pipe about 2 above the top the 12 inch stack so the heat can escape and it creates a storm collar. Will then have threaded screws with captive nuts on the 12 inch jack that I can adjust inward for tightness to use in supporting the stack running inside of the jack (kinda like a Christmas tree holder).
Now for the Math used in creating an ellipse. My roof is a 6 - 12 pitch = 22.5 degrees. I chose to do everything in inches.
The Width of the hole in the roof plate is established. 12 inches. Length is the hard part. As you know, you need create an oval so you need to figure out the long points of the ellipse.
I drew it out on a piece of paper. You draw a vertical line that is 6 inches (in this case; for a 8 - 12 pitch you would draw a line that is 8 inches). Then draw a horizontal line that is 12 inches. In my example, the third line of the triangle to connect the two ended up being 13 3/8. This means the long point of my oval is 13 3/8 or 6 13/16 on either side of the midpoint. Now you just draw the oval by using a string and two pins (There are directions for this on the web).
I welded it up last night, will seal it with roofer's caulk and will put it up this weekend.
Just note: The 12 inch base of my triangle is established because that was the diameter of my pipe. If you are doing the same with a 10 inch pipe for example you would need to figure out your rise/run over 10 inches. This is where knowing the degrees of pitch would come in handy...
I hope this helps!
64936494
I could not handle the thought of paying $250+ for a roof jack so I started working on an alternative. I was going to do a trash can jack, but ended up looking at a roof jack and saying "i can make that myself."
So, the hard part is the math...and a simple explanation of the math was hard to come by...that is what I needed. I am no expert, but I thought I would offer what I learned in a way that I hope is easy to understand.
Here goes:
I got a 5ft 12" stack with a 12" to 10" collar. I will run the 10 inch stack pipe up through the 12 inch one and will have the collar affixed to the stack pipe about 2 above the top the 12 inch stack so the heat can escape and it creates a storm collar. Will then have threaded screws with captive nuts on the 12 inch jack that I can adjust inward for tightness to use in supporting the stack running inside of the jack (kinda like a Christmas tree holder).
Now for the Math used in creating an ellipse. My roof is a 6 - 12 pitch = 22.5 degrees. I chose to do everything in inches.
The Width of the hole in the roof plate is established. 12 inches. Length is the hard part. As you know, you need create an oval so you need to figure out the long points of the ellipse.
I drew it out on a piece of paper. You draw a vertical line that is 6 inches (in this case; for a 8 - 12 pitch you would draw a line that is 8 inches). Then draw a horizontal line that is 12 inches. In my example, the third line of the triangle to connect the two ended up being 13 3/8. This means the long point of my oval is 13 3/8 or 6 13/16 on either side of the midpoint. Now you just draw the oval by using a string and two pins (There are directions for this on the web).
I welded it up last night, will seal it with roofer's caulk and will put it up this weekend.
Just note: The 12 inch base of my triangle is established because that was the diameter of my pipe. If you are doing the same with a 10 inch pipe for example you would need to figure out your rise/run over 10 inches. This is where knowing the degrees of pitch would come in handy...
I hope this helps!
64936494