Wood Magazine article...

[Owen Gregg]

Hey all,

Just got the new WOOD magazine in the mail and saw the article on the suspended wood ceiling. Looks like a nifty idea, but I was wondering what size of panels you could make before sag became an issue. I noticed they say you can "customize" the size, but I would think there's a point where more reinforcement than what is shown would be needed. Just a curiosity, interested in hearing thoughts.

Thanks.

[Grant Morris]

I haven't read that article but I have installed many a suspended ceiling. Correctly installed suspended ceilings can hold a lot of weight. Sag won't be an issue unless the roof that you are suspending from has problems. The key for a suspended wooden frame that holds the panels is going to be how the suspension wires or rods are attached to the frame.

[Dan Oelke]

After seeing the teaser for that article last month I was really waiting to read it as I've wanted a wood ceiling in my basement, and really don't like the look of normal suspended ceilings.

Owen - If I understand you correctly - you are asking how big a single square/panel could be before you get issues with the plywood sagging. I don't know - but I'll hazard a guess or two.

With the backing ribs - I'm going to guess that you can make your panels pretty big - 3' square or better. Those ribs give you a lot of strength. If I remember correctly, they were 1" high ribs. That means you are looking at how much sag you would get in a 1" high board. Not a lot with the small amount of weight in those panels.

If you are worried, you could put 3 or 4 ribs on the back side. Maybe use half-laps. You can also extend the ribs to be closer to the edges so there isn't room for the skin to sag between the supporting rail and the rib. If you really want to go hog wild or want really big panels you would probably make it like a torsion box with ribs every 8"-12" and a skin on both the top and the bottom. Even with just 1" high ribs you'll have a lot of strength because of the geometry of a torsion box.

Now, even if your panels do sag a little over time, you can always retrofit extra stiffening ribs later on. It might take some serious clamping to straighten them while you put on the extra ribs, but it would be doable.

Final idea - if you are really concerned - make up a panel and suspend it in your shop for a couple of months. Put a book in the middle to give it extra weight and accelerate the testing. That will give you a good idea if it will sag over time.

[Owen Gregg]

Hi Dan,

You were right about my original question. The panels I'm considering are 4' squares and 4' x 6' rectangles. The ribs on the back of the panels I think are actually 2" high, whereas the reinforcing strips on the back of the actual grid are 1" wide.

At first I thought it wouldn't be a problem, I'd just put a hanger in the middle of the panel. Then I remembered the working space I'd have with the panel in place:( .

[Dan Oelke]

4 x 6 - that is pretty good sized.

Even so, using 2" high ribs should give you plenty of resistance to sag. I just think that you would need 3 ribs one way and 4 or 5 the other. That way you have only a foot or less between ribs.

Just thinking about hardwood strips - I have used 1.5" strips that held a fair amount of weight with very little sag. So the problem isn't the sag in the ribs, but that the 1/4" plywood will easily sag under it's own weight.

Going to the sagulator..... If you use their calculations for fir plywood....
A "shelf" that is 48" wide x 12" deep and 0.25" thick and is 3.2lbs in weight will deflect 0.25" (1/4 ply is about 0.8lbs/sq ft). Change that to be just 24" wide and you deflect only 0.03"

Hmmmm - going from that calculator, I would think that a 2' square panel wouldn't sag so much as to need stiffeners. So maybe my gut feeling of wanting a stiffener every 1' is overkill and you could go to 18".

The other problem you will have with bigger panels is that you typically put wire hangers from the joists above to your grid every couple of feet. With panels that big you will probably have problems pushing the panel up and sliding it to the side because you will be hitting the hanging wires. You will also need more "headroom" between your rails and the joists. That space is needed so that you can push the panel up and turn it enough to come down through the opening at an angle. I think with the bigger panels you won't be able to turn them to enough of an angle without more headroom.

[Lee Schierer]

Hey all,

Just got the new WOOD magazine in the mail and saw the article on the suspended wood ceiling.

Wow, I think mine came over a week ago. They must have slow delivery to Omaha. :confused: Or else your spouse is like mine and reads them before I get them since she is home when the mail comes. :D

[Owen Gregg]

Yeah, Definitely need a bit more thinking on this one as far as layout goes. I'd like to make it look nice, but the odd sizes are probably just a bit of overcomplicating things on my part; no real reason to not use 4x4 or 2x2 panels other than to be "different." Just seemed like a great alternative to tearing down a plaster and lathe ceiling and putting up/finishing a new drywall one. Figured I could do the wooden panels nearly dustless, whereas drywall would be anything but. Very important factor with 2 new babies in the house.

Lee-Very possible it's been here for a week. It was underneath one of my wife's magazines, so lord knows how long it was there. I'm not a hug fan of US Weekly;) .