Roof Strength Question

[Scooter]

Sandwiching 1x1 or 1x2 between two layers of ply is a very strong and lightweight method, very similar airplane wing spar const.

[Denny Unfried]

Probably as important as the size is the type of wood used. Something soft like fur won't give much strength or hold screws well. I used 1 X 2 clear poplar on 12" centers because it's very stable, strong, glues and holds screws well. Here in the West the termites don't care much for it and it is dry rot resistant. Might as well build with good materials since it's next to impossible to redo roof ribs. Just my 3¢ worth.

Denny

[David Grason]

I've also been concerned about what I'm calling "inferior" building materials that have been specified in the Kuffel Creek plans. Primarily, the Kuffel Creek plans specify 2x2 pine roof supports, 2x2 framing material and ACX plywood for the sides. Having gotten past the halfway point in my boat building project, I'm actually appalled at the gnarliness of this nasty (IMO) material called for to build a teardrop. My boat is made of Honduran mahogany for the frames and sheeted with Okoume BS-1088 marine ply. The stuff is a pure joy to work with while the ACX is just plain crap. The ACX even takes on a new warp every time the tempurature and humidy changes.

But here's my final opinion. (at least at this point. I may have a NEW final opinion later. <embarrassed ha ha> ) The farther I get in my project, the more I realize that, as everything goes together, the teardrop takes on a synergistic strength because everything works so well together. The warping of the ACX will stop because each piece will be so well fastened and glued that the wood won't be able to warp. The roof supports will also draw strength in monocoque fashion from the inner and outer skins not to mention that these plys are tortured into place. Then there is the solid foam insulation. The interior will be cabinet grade veneer and the exterior will be covered with sheet aluminum. So why use the expensive stuff when everything will have sufficient strength for the task and will all be covered anyway?

At first I was thinking that Kuffel Creek was dropping the ball when everything else Kevin had done had been with an eye toward real quality. But now, I think everything will be just fine and I stand corrected in my thinking. I think that combined with everything else, the pine roof supports (rafters) will be more than satisfactory.

[Arne]

Was watching a 'this old house' segment recently and I noticed Norm mentioned he sizes up a contractor by how they store their wood. Off the ground, covered up (from rain) and strapped together till used (wood can develop an incredible warp when it dries out).....

One of my concerns was building the wall and cutting out the door... would the door warp?..... It has worked out fine, maybe a bit of change, but not enough to mention..... I used 1/4 inch ply in and out with 3/4 in between.. going to a thicker middle piece would make it even more stable..

Just thought about it. If I build another one, I'll brush on some epoxy around where the doors will be cut out... That would make it more stable, as well... just 2 or 3 inches inside and out.. don't want no stink'n warped doors to deal with...

[Scooter]

The farther I get in my project, the more I realize that, as everything goes together, the teardrop takes on a synergistic strength because everything works so well together.

Bingo!! My greatest joy in building things is seeing the combined strength of ordinary "flimsy" materials transform into a functional thing of beauty. I'm no poet but I think most of you know what I'm talking about.

[bdosborn]

I'm pretty happy with how strong my roof bows turned out. I used two 1x2 poplar boards glued together.
Bruce