wall material?

[vegask]

I searched but could not find this exact case.

I am using 3/4" AC plywood for my inner wall and plan on using 1/8 baltic birch for the interior. I found a shop in town that sells the nice 5x5 sheets at a reasonable price. Would it be ok to use 1/4" (6mm) baltic birch for the exterior wall? Seems like it will be fine but I cant find any cases where people do this. The tear will be skinned in .040 aluminum also.

[tony.latham]

I built a 4x8 that was skinned with 1/8" BB on the inside and 1/4" underlayment plywood on the outside. I think your 1/4" BB would be fine as long as you seal it well with either The Mix or epoxy before you sheath it with the aluminum. The underlayment plywood I buy is better than 1/4" AC and cheaper–-the inner layer is solid with no knots. I once soaked a piece of scrap in a bucket for a month and it never delaminated.

Tony

[dales133]

I agree with tony.
Mines stick frame 3/4 and i went for 6mm internal and 1/8 external but it ends up the same strenth and wall thickness.
Works out good for doors and stuff too

[noseoil]

I used 3/4" exterior plywood for the "skeleton" frame, then 1/8" BB on the inside & outside, covered with .040" aluminum. All the 1/8" has to do is keep the insulation in place & glue to the inner 3/4" panel until the walls are buttoned up & finished. The 1/8" saves money over 1/4" & weight as well. If you're using .040" aluminum for the skins, 1/4" isn't really necessary.

[vegask]

I built a 4x8 that was skinned with 1/8" BB on the inside and 1/4" underlayment plywood on the outside. I think your 1/4" BB would be fine as long as you seal it well with either The Mix or epoxy before you sheath it with the aluminum. The underlayment plywood I buy is better than 1/4" AC and cheaper–-the inner layer is solid with no knots. I once soaked a piece of scrap in a bucket for a month and it never delaminated.

Tony

I am not familiar with underlayment, is that something a big box store would have or do I need to find a lumber yard?

I used 3/4" exterior plywood for the "skeleton" frame, then 1/8" BB on the inside & outside, covered with .040" aluminum. All the 1/8" has to do is keep the insulation in place & glue to the inner 3/4" panel until the walls are buttoned up & finished. The 1/8" saves money over 1/4" & weight as well. If you're using .040" aluminum for the skins, 1/4" isn't really necessary.

This is extremely helpful, I was wondering if I could do that, now I may just do that.

[MtnDon]

I am not familiar with underlayment, is that something a big box store would have or do I need to find a lumber yard?

Very common product in Lowes, HD, Menards, etc. Usually about 5 mm thick. Also usually made from sustainable "factory forests".

[tony.latham]

I live in a one-lumber-yard town, three hours from Lowes, Home Depot and Menards.

On the forward portion of this wall, you can see the underlayment ply. Much higher quality than AC and my retail price here is $22 a sheet:



I've been told that it's some type of Russian birch, but who knows?

Tony

[vegask]

I need to go find some of that, thanks.

On an un-related note, still trying to find what "Scotts Workshop" used in his youtube series for his template. He referred to it as "underlayment but it was larger than 4x8 (4x10 more likely) and was super thin and light from the looks of it.