Orientation of spars?

[Donutboy]

I'm ready to fit the walls and install the spars. Is there a preference for installing the spars this way:

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versus this way?

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It seems that the first method would allow for more insulation, whereas the second method would allow for 3/4" more headroom (assuming 1 x 2 spars were used). But are there other advantages to either method?

[doug hodder]

Yes...more strength! Less chance of bowing once the roof skin is on giving you a flatter roof surface. You'll also want as much insulation in the ceiling as possible given what you are using for spars as that's where all the heat rises. Just my opinion. Doug

[Steve F]

I did the spars in the roof, front wall and hatch as per the first pic. As Doug says more strength and thicker insulation. Mine is 2" thick in the roof and front wall where as the side walls it is 3/4".

Cheers
Steve

[asianflava]

I used method 2, most use 1. I wanted more interior room and didn't need more insulation. It is plenty strong even though I sheeted it with 1/8in ply. The radius also lends a lot of strength to it.

As you'll find, there isn't any one way to build your trailer. They are all unique.

[jplock]

I agree there is more strength in the first example, also when installing the spar put the crown side up ( as example look at the spars before installing the you will usually see that they may be a little warped one way or the other. Put the bowed side up. Then when weight is applied with the skin it will tend to flatten out.)
jplock

[Donutboy]

Thanks for the advice everyone. I'll be using the first method. That was my plan all along, but I started to outthink myself. Couldn't have been the late night brewskies, could it?



Reading the replies reminded me of why I went to the effort to insulate the walls in the first place: because it gets freaking hot in Texas in the middle of the summer!!!

[bobhenry]

Mine were 1 1/2 by 1 1/2 I didn't have to decide just put crown up.
I cut them from 2x12 # 1 grade southern yellow pine ( about 45 to 50 percent stronger than SPF lumber) The rabbet fits into a 3/4 deep by 1 1/2 wide notch cut into the side I screwed thru my sides into the spar at an upward angle and used glue generously as well.