I am doing a deck that is rectangular (28’X13′) with one long side against the house. The two short sides are actually about 8′ long to the corner then it bows out on along the other long side to it’s widest point (13′) and then back to the 8′ other side. Can you see it?
Well, I am having trouble figureing out my board sizing and mitre angles for the curve on the deck and the railing. The decking with go with the house, but will be “framed” with a band of decking all the way around and mitred on the corners. Cany anyone lend me a hand so I don’t need to call my elementary math teacher? He would be so disappointed.
Regards,
WIT
Replies
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The two times that I did this, there was a 6' patio door in the center of the wall, and I was able to establish my point for the radius inside the house. If you don't have this luxury, I suggest using the ol' neandrethal method of getting a piece of 1" pvc of an appropriate length and bowing it to the radius, marking the cuts for ends of your joists and going from there.
ok, I just did the math and according to your measurements, the radius needs to be 22' 1-1/8" so I guess you can scrap the "establish a point inside the house" theory. I'm voting for gluing two 20' pieces of pvc together on this one.
Or you could draw everything out on a big flat surface and just measure every "joist"
You could probably get a pretty close to accurate aproximation of the angles to cut them at two.
Mark,If he's at 28' in width and 13' from the house I get 14'7/16" for the radius. Unless I don't understand what he is saying but I think Huck's drawing shows that without the measurements though. Maybe my brain is fried because I played miniature gulf today with my son and it was pretty hot.Joe Carola
I'm with Mark "If I were a carpenter", I come up with a radius of 22' 1 3/16" (which he rounded to 1 1/8).
Square 1/2 of span, divide by rise, add rise, divide by 2.* [14' squared, divide by 5, add 5, divide by 2. I come up with 22.1 feet.]
or...Rise squared plus half the width squared divided by twice the rise.*
[5 feet squared, plus 14 feet squared. divided by 10 feet. Still come up with 22.1 feet.]
* link
edited to add: I think the problem is with the 13' from the house. The deck is 13' from the house at the extremity, but the deck is rectangular for 8', then the only the last 5' comprises the rise of the arc. That and the miniature golf.
Edited 5/14/2005 10:17 pm ET by Huck
Huck,If it is like your saying with a 28' x 8' rectangle and then 5' past that to give it 13' off the house it would have a 28' width and a 5' height and I would come up with a 22'1-3/16" Radius also. Picture #1 would be what I think your talking about.My first post I thought it was a 28' width and a 13' height giving it a Radius of 14'7/16" as in picture #2.Maybe Wit can tell us which one it is or I'll give up miniature golf....:-)Joe Carola
Thanks for the drawings. It was actually the first with the 8 X 28 rectangle and the 5' curve.
I have all of the posts, beams, and joists located. I am having issues with the skirt. HO does not really like lattice work and their previous deck had 1X3 boards attached vertically around the deck.
Regards,
WIT
If you are talking about the rim-joist, then I have always just used 1/2" plywood laminated (built up in layers). I just rip the plywood the same width as the joists and bend it around the ends of the joists 3 times using ext. glue and screws to give me a 1-1/2' thick rim joist that has a nice curve to it.
Your illustration would work except the pivot point is somewhere in the basement of the house. Any other ideas? I don't have a way to accomplish this...
Regards,
WIT
of course.. It helps to read all posts prior to responding. If any of you have any photos of curved decks and frameing can you send them on? I am struggling defining the skirt detail.
Regards,
WIT
I would lay it out on some scrap plywood or osb sheets somewhere there's room enough. That's just me, but others have mentioned bending something to approximate the curve.
wit... lay it out in CAD , then plot the points...
or have a local designer lay it out in CAD.. then plot the points
as you can see from Huck's drawing... there are a lot of points that can be located
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once those perimeter points are located you can lay out the true curve with battens in exactly the same manner boat builders loft the curves
battens are easier to work with that pvc
Mike Smith Rhode Island : Design / Build / Repair / Restore
Edited 5/14/2005 6:13 pm ET by Mike Smith
Does anyone have an secrets for determining the width of the material needed to get the curve out and also some strategy for determining the size of the segements that go around the curve? Things like number of pieces, angles etc.
Thanks so much!
WIT
You should be able to solve most of this stuff yourself if you're going to tackle a project like this. Is this your own house or are you hired to do it for someone else?
Try drawing it out at a 1" scale. Get some plywood and draw it out full scale. There's two secrets for ya, any more you have to pay for.
Mike
It's a rare carpenter who could/would use math to calc something like that. Most of us use 'descriptive geometry' to do odd shapes, angles, curves, etc. If you can't get inside the house to swing a trammel arm, I would go with Mark's idea and bend a piece of pipe or wood, starting at the 8' points, and pull it out to 13' feet in the middle. If you have the joists already in place and run wild, you can mark them carefully against the pipe and then take your cut angles with a bevel gauge.
Picture-framing the decking is a nice look. I am just finishing a curved deck and decided not to do that because I don't want a spot between the edging and the decking ends where water and grit collect. I also didn't want the extra framing to deal with the ends of the decking (that depends on the width of your band, or course). However, if you do it, I would first bend the rim joist around the ends of the joists, and then find a method of 'tracing' that curve onto the decking. I bent the rim for mine out of three layers of 1/2" PT plywood and guerrilla glue.