Roof question

[Tiki Dude]

Aloha from Olympia,

I installed the front section of the roof yesterday sucessfully. I was going to do 2 layers of 1/8" luan on the tight curve section but it appears to be strong enough without an additional layer. I figure with epoxy covering it should be o.k. Any thoughts?

I liquid nailed it to the beams and stapled the #$@&^% out of it.

Mahalo,

Tikidude

[Arne]

if the 'rafters' are close enough, I would think it would be ok "under normal usage".....

My pie in the sky for a potential no. 2 would be to think it through and all wall and ceiling ply would be 1/8"....

Potential disaster if not planned out..... and lots of "do not push here" signs...

Yes, I think it can be done.

[randy chesnutt]

what you do is give it a good woooop with your hand and then decide if you should add another sheet are not

[madjack]

what you do is give it a good woooop with your hand and then decide if you should add another sheet are not

...stand back about 20 feet with a 2" rock and........................
hey if it works for you not much else matters does it...but a good whoooomp test of some sort would not be a bad idea
madjack

[angib]

...stand back about 20 feet with a 2" rock and.........................but a good whoooomp test of some sort would not be a bad idea

This is known (sorta) technically as the 'ball-pein test' and is used for high-tech laminates. There are lots of structures that can be made superlight in carbon fibre and they will have sufficient overall strength, for example to be stood on, but they won't survive being hit hard by the ball of a ball-pein hammer. Using the hammer makes a comparison of different test pieces fairly reasonable. Of course it started as a joke, but then was found to be a decent workshop test!

Usually you have to try impossibly hard (or use a heavy hammer) to puncture 3/8" ply, 1/4" ply is doable with a little effort, but making a hole in 1/8" ply is easy. 1/8" ply with a thin epoxy/glass skin is harder to puncture, but still not that hard. It really depends on whether you want something that's actually bullet-proof....

Andrew

[Arne]

I have a section on the front of my tear where the 2 sheets of 1/8" ply are not snug against each other. It performs well in everyday use, but when I push on it, I can feel a gap of about 1/4". It came about because I was planning on installing a front window and had made a flat on the front of the tear about 12" high. I could get the first sheet to curve up from the bottom, flatten out on that section, then curve up over the top. The second sheet was not as friendly, so with glue drying, I just gave up on the idea and let it set its own curve.... The gap on each side of the tear was just filled with body filler.

Point is, in everyday life, it it not a problem. Even if I push on it it just deflects till it hits the sheet underneath. I think building with 1/8 is fine as long as it is backed with insulation, and any points where it might get a load are beefed up.

In the roof, where it might encounter snow load, that would have to be given consideration. Also, I would not use 1/8 unless I were to use a coating that would increase its stiffness. Since I like using cpes and uniflex, that would be my choice, but I've also used 'wood hardeners' that have greatly increased the stiffness of wood and are very easy to apply.

[asianflava]

I had my hatch leaning on a wall outside my garage. One windy day I found it in the middle of my driveway. When I checked it out it was scratched up from sliding across the concrete and there was a hole. When it fell over, it fell onto a spray can which punched a hole thru 2 layers of 1/8in ply which was epoxied. I'll just put more epoxy, on it then cover it with aluminum.