Spacing of spars when using 1/4" plywood

[zlamb0002]

I will be insulating all the walls, floor and ceiling. I was thinking of putting a spar every 12" and was wondering if that would be sufficient.

[48Rob]

Depends on what you're using for spars, and what size the spars are.

Pine, Poplar, or similar wood 3/4" thick x 2" wide spaced at 12" should be enough.

Rob

[vrooom3440]

Wouldn't it depend on how the insulation is fastened to the insulation?

If you glued the entire surface of the interior and exterior plywood to the sandwiched insulation, couldn't you only run spars where you needed attachment points?

(around the perimeter, around edges of doors and windows, probably one vertical from top to bottom where door hinges attach in wall, where front/rear inside cabinets and bulkhead walls attach)

[48Rob]

Maybe I misunderstood the question?

I always understood "spar" to mean a horizontal support.

In the context of building a trailer, to mean the horizontal roof supports.

Were you asking how far apart the roof framing should be, or were you asking something else?


Rob

[planovet]

In his second post, he sounds like he is talking about the wall framing. The first post DID mention the ceiling. I also see the word "spar" and think of horizontal support, not vertical. I'm confused.

[zlamb0002]

Sorry for all of the confusion, I thought that a spar was all framing not just horizontal.

[48Rob]

No need to be sorry, glad you got us straightened out!

Now that we all know what it is we're talking about, we can give you better answers and information you can use.

I haven't followed all your posts, so don't know exactly what type of construction you plan on, and all the dimensions of the planned material, but...

If you plan to use 1/4" ply on the outside, and you'll be insulating, then I'll guess you'll be installing 1/8 or 1/4 on the inside too?

If so, then 12" spacing for the wall framing will be fine.
You could go as much as 16", but the weight savings of a couple less framing pieces isn't worth the loss of rigidity.
If you glue and nail, or screw and nail both inside and outside ply to the framing, you'll end up with a very strong wall!

For the roof, 12" is good, but no wider if using 1 x 2.
I like mine strong...if I can't walk on the roof, it isn't built well enough...
If the roof is paper thin, and I have to "be careful", I might as well have a tent.

Good luck with your build!

Rob

[mikeschn]

If you use 1/8" plywood, and that's pretty thin stuff, it would behoove you to strengthen it any way possible.

Here's a couple ideas...

Use 8" spacing on the spars.

Use the R-tech insualtion, and glue the plywood to the insulation

Put a layer of fiberglass on the outside of the plywood

Okay, so that's a few ideas...

Mike...