Template for 10″ hole in a 6 in 12 roof
I need to cut my 10″ chimney pipe hole through an 8 1/2″ roof sandwich (plywood top and bottom and 7″ insulation). Obviously if the pipe is plub the hole isn’t round… Anybody got any resources for how to find a template for that hole…. I figure 6 in 12 is pretty common….
Thanks for any help you give.
Replies
Well, conveniently enough a 6/12 results in a 45d angle -you could chop a spare piece of pipe at 45d and use the end as your template.
Or, since we've got a right triangle, you could calculate the length (14.14 inches, and the width stays the same) and just sketch out the oval.
12:12 is a 45 degreee angle, 6:12 is not. Its 26.5 degrees.
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Edited 6/8/2009 3:12 am by Huck
Oh jeez, you and Mongo are right. I should know better than to open my mouth after midnight.
Sorryyyyyyyyyyyyyyyyy
no worries, mate. been there done that. part of being human.View Image"...everone needs to sit on a rock, listen to the surf, and feel the ocean breeze in their face once in awhile."
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Okay, it's a little late at night, but I believe 12/12 is 45 degrees.6/12 is a little less than 27 degrees. Don't have the exact number as I'm without calculator.Cosine of 27 is a little less than 0.9, your 10" pipe diameter divided by 0.9 is about 11-1/8". Since I guessed low, I'd say add on a bit, 11.25 for a tight fit.So an oval 11.25" long and 10" wide would be close. Obviously you'd add on for clearance as needed.
THanks, great help. I'll do a test piece and use it as a template.
Another very easy way is to stand a piece of 10" pipe where you want it and use a level to plumb it. Or set the pipe on a small 6/12 wedge-shaped piece of scrap wood.While holding it in place, run a pencil around the circumference of the pipe. Or elastic a pencil to a paint stick or something similar if you ned something longer for the scribe.
Draw a circle on the floor, laser plumb bob 4-8 spots on the circle up to the ceiling. Connect the dots.
Steve
Or let the laser do the work and burn it thru.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
"If Brains was lard, you couldn't grease much of a pan"Jed Clampitt
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"Or let the laser do the work and burn it thru."
Ah, would that be the PLS-5000 X-Treme? ;-)
To the OP -- I'm no sketchup artiste, but I'm thinkin' you would be able to make a template for that fairly easily with SU.Mike HennessyPittsburgh, PAEverything fits, until you put glue on it.
I'll tell you what, that 89 dollar stanley fatmax plumb bob laser is one of the greatest things since sliced bread. Does what it needs to do and nothing more. I use it all the time.
Add some lenses to it and burn baby burn!Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
"If Brains was lard, you couldn't grease much of a pan"Jed Clampitt
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Its an oval shape. You can create the oval using a piece of string and a couple of nails if you can calculate the major and minor axii.
Almost any basic drawing program is going to be able to draw an ellipse with the major and minor axis specified. Output the ellipse to a large-enough sheet and use it as a template. You want I send you a PDF file?
I wouldn't object to PDF as I'm always jammed for time! (I can deal with Autocad 2000 too). Turns out, I might need it for 14" rather than 10. Checking!
This *might* work...
Do a google search for an ellipse, that's what you have more or less.Very simple to draw out, the website explains it better than I.Make sure you have proper clearance for the chimney pipe. I found the best way was to draw the oval on cardboard or plywood. Put a nail thru the center and center the nail and template on the shingles.
I mark the shingles out and cut them with snips first.Then I cut the sheathing using the shingle cutout for my lines.
mike
You guys are overthinking this.
This isn't piano building. The biggest problem is getting a control point thru the 7" thickness so one can work from the outside.
Find the center of the pipe on the interior. Drill thru plumb to the outside with a long bit or run a SIPS screw thru. Take the shingles up around the control point. Set the flashing boot on the roof centered on your control point. Reach inside and mark the hole at the base of the boot. Get out the sawzall.
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<<You guys are overthinking this.>>You do know this is the internet, right? ;-)
Hey, I think I'll try it that way! THanks.
I think even less: Cut a hole, make it bigger until it's big enough. Always works.
I've tried that, too, but I always have trouble making the hole smaller after too many measurements :)
I thought mine out very carefully, drew the ellipse and cut it, then decided to sawzall it out to the full size of the flashing boot. It's the best of both worlds.
You guys are overthinking this.
This isn't piano building. The biggest problem is getting a control point thru the 7" thickness so one can work from the outside.
Find the center of the pipe on the interior. Drill thru plumb to the outside with a long bit or run a SIPS screw thru. Take the shingles up around the control point. Set the flashing boot on the roof centered on your control point. Reach inside and mark the hole at the base of the boot. Get out the sawzall.
+1
The only thig I will add is to be certain that the hole you cut meets clearances to the pipe. Sometimes, the opening in the flashing is a little tight on the top and sides, the bottom is usually OK (top, sides, bottom referenced as looking at the hole from above the roof).
The flat portion of the flashing that ends up under the shingles is usually big enough to allow a 1" or so overcut.
Make sure your hole going up from inside is plumb.
I used this website to draw the ellipse. You can create as many points on the ellipse as needed and then connect the dots http://carverscompanion.com/Ezine/Vol2Issue4/Judt/Ellipses.html