Using wood under the Aluminum

[Sean the Leprechaun]

Hi All. I am about 2/3rds done with my Generic Benroy build. I have just finished insulating and have decided to put .040 mill finish aluminum on the sides and top.
My question to all is "should I use 1/8 Luan or Baltic Birch under my Aluminum skin on the roof / hatch. Why do the plans call out for using 1 pc of Birch or 2 skins of Luan of the same size?

 

[Miriam C.]

oh oh. We dropped the ball here. So Sorry Sean. If you haven't figured it out yet you just need 1/4 inch of something. I doubt the kind of wood makes too much difference under aluminum.

PS---are you done yet?

 

[madjack]

Sean, my take is you don't need more than 1/8th" material under the AL...in fact, with .040 or thicker AL you don't actually need any substrate at all...for many years, the most popular plans out there, where the Cubby plans from Kuffel Creek and they used no ply under the Al roof skins...the acknowledged leader in the commercial TD field(Camp-Inn) used no ply under the roof skins...on our last build we did the same and will continue to do so on any future builds...this is not to say that you shouldn't use a substrate...just that it is not absolutely essential.....
madjack

p.s. we do put our ribs(struts) on 8" centers..........MJ

p.s.s. by the way...where are da pics...we just luv 'em...doanchano

 

[johnthom81]

Madjack, thanks so much for that. This answers my question of whether or not to use a substrate under the roof skin. The 8" center ribs makes good sense and should give better strength against that occassional football that might hit the roof. My motorcycle trailer is out being lengthened from 7' to 10', then I can get started with my 1st build also.

Thanks!

 

[2008hiloguy]

Hi there,
this is an old thread but i am hoping you see this. Did you end up going without a substrate? How did it go?
Question how do you attach the aluminum without a substrate? Just use adhesive on the cross spars and top framing of sidewalls?
Thanks in advance!
mariann