Using aluminum seemed so simple

[OzarkRay]

So, I'm at the point where I'm ready to put my .030 aluminum on (just the roof) and I've got a couple issues I haven't figured out.
-Is this just supposed to go on top of the plywood (after I've sealed the joints and edges with fiberglass tape and sealed the wood) or should I put something like roofing felt or some sort of weathertight membrane down underneath it? To me, I see that this would help isolate the hot aluminum even more, provide another failsafe in case water gets through the aluminum somehow, and would help absorb some of the impact if the aluminum gets hit by a rock kicked up from the wheels or other road debris. Having a big dent with cracked plywood underneath sounds like a real pain to fix.
-I'm making a 5X8 and of course, all I can find locally is 4X10 sheets. There's going to be some cutting and riveting going on. Is it better to do it in 4-ft chunks and have a horizontal line of rivets, or should I cut the pieces lengthwise and have a vertical rivet seam down the middle? Which is more water tight?
-My aluminum is black on one side, white on the other. I had planned on having the black side out, but when I think about it, it seems like that would get really hot in the summer and would hold heat even after the sun went down. Looks-wise, I think the black would look much classier. But practically, I wonder if we'd fry inside this thing (I'm not installing an AC, just a good quality exhaust fan).
Hoping to have this ready by the first of the year! My wife will be glad to have the carport cleaned out. She hasn't given me a deadline yet...

[woodywrkng]

I reckon if I were in your shoes I would make a roadtrip to whoever carries 5' sheets. The result will be so much nicer without any joints. It was easy to find 5' sheets here in central Iowa. The roofing felt is an interesting idea, perhaps someone else will have a good opinion on that. Personally, I applied some strips of urethane caulk between the plywood and aluminum so the metal wouldn't "oil can", but I think plenty of people let the aluminum float in the center with no problems. Go with white on the outside. It would be easy to touch up if scratched as well as much cooler.

[Roo Dog]

OR,
Pre painted steel sheet all over.
Glued straight onto the ply.
Over two years old no problems.
RD

[tony.latham]

I've never heard of putting anything between the aluminum and the wood. A black tear? I'm thinking you'd fry on a hot summer day. I suppose it depends on your temps and if you've built your walls and ceiling with insulation.

There have been some real success posts on this forum with seaming the aluminum horizontally. Lapping it with a good sealant. Start searching.

Can I come down and borrow that tear some summer (as long as it's not black)?

TL

[KCStudly]

Look at aggie79 (Tom's) Silver Beatle build thread. He demonstrates very clearly an excellent method for lapping horizontal seems.

[OzarkRay]

Look at aggie79 (Tom's) Silver Beatle build thread. He demonstrates very clearly an excellent method for lapping horizontal seems.

Thanks, that answers all my questions. Yesterday, I stumbled upon a trailer parts place in my area that does have the wider rolls of aluminum. Of course, I already purchased two 4X10 sheets a month ago, so I figure I'll go ahead with the horizontal lapping. I've already got plenty of ideas for how I'll make the next one differently!

[crazycyclist]

I would ditch the 4x aluminum sheets and go with 5 foot wide for the roof. The extra expense would be worth the assurance that you will not have a seam in your roof.

Not to mention the time you will save in a much simpler skinning process.

[jonw]

Granted the 5 foot wide pieces would be easier (ie. no seams) but since you already purchased 4 foot wide aluminum I wouldn't shy away from using it. Seams are not the end of the world if done well.

As for backing I just have mine "floating" on the roof spars and held in place by the holes drilled through the side molding and screwed down. However my aluminum is heavier .040 in thick. With your lighter weight aluminum you might want some ply backing but you could still just let it float if you want.

[madjack]

Granted the 5 foot wide pieces would be easier (ie. no seams) but since you already purchased 4 foot wide aluminum I wouldn't shy away from using it. Seams are not the end of the world if done well.

As for backing I just have mine "floating" on the roof spars and held in place by the holes drilled through the side molding and screwed down. However my aluminum is heavier .040 in thick. With your lighter weight aluminum you might want some ply backing but you could still just let it float if you want.

I did virtually the same thing, cutting my .040 4x10 sheets into 4x5 sheets and turning them side wise...they are floated directly onto the spars with no underlayment ...I do have a front box built directly on the tear and covering the first two feet of the roof...I located the AL and shot a couple of staples into each side edge to keep it place and then my trim, which is screwed down, captured and holds it in place...

...at the seam, which overlaps about 4"(2" orso would be sufficient) I used urethane windshield adhesive/sealant and flat head SS screws set 2"s apart...this gives a "riveted" look with a screws fastening capacity...I predrilled all my holes, and squirted a dab of sealant into each hole as well...no leaks after five years.

I plan(one day) to coat all the roof in bedliner and since I live in Louisiana and camp in generally well shaded camp grounds, I wasn't worried about the sun and heat with a Fantastic Fan vent...I do have a PetCool AC unit but rarely use it, especially since, I am never in the tear during the daylight hours...doit like you want it...good luck.......
madjack

[tony.latham]

When it was all-said-and-done. The aluminum was about the easiest part of my build. Feel better now?

It's the truth. I had a side pattern to use to cut my sides with. I found my jig saw with a metal blade was just the ticket. I cut 'em a bit proud, just to make sure. Using a trim router bit worked great –even at high speed.

So relax. For me, the hardest part of the aluminum was finding the shiny stuff.

TL