Properly put together cribbing

[unitlink]

So I'm wanting to create some cribbing for our 5th Wheel since our drive slopes downward a bit. The legs have to be extended pretty far and I think I would feel better if I had some cribbing to place underneath.

While I did Google how to build some cribbing, I'm kind of looking for some instructions tailored more for trailers.

Anyone have a quick how-to on how they built one for their trailer?
What would be the maximum height you would build on up too?

[Old-Biscuit]

NOT what you want to use.......




You want solid wide cribbing so that weight is spread out.

Example.....




NOT a fan of this.......plastic gets brittle




NOT a fan of this kind of cribbing.....blocks all going same direction can be unstable if any movement going on inside 5vr

[MnTom]

Here are the basics: Wooden Cribbing Basics - Boron Extrication

[easdsa]

What's the best practice regarding blocks under the front legs and rear stabilizers? I understand that a sloping site will require a different practice, but assuming a fairly level site, should I build up the cribbing so that the jacks and stabilizers don't have to extend very far, or should I keep the cribbing fairly low and let the jacks and stabilizers extend as far as needed?

[ralphie]

WRT height, I would make the cribbing roughly no higher than the average ground height you normally experience when set up in a CG, and neither under nor over extend your front jacks accordingly. Also, ensure the cribbing is plumb.

[unitlink]

Originally Posted by MnTom

Here are the basics: Wooden Cribbing Basics - Boron Extrication

So looking at those examples, doing a 3x3 would be ideal for RV's correct?
In that case it would like I would use 4x4's and go about 3 to 4 levels high with the base being 4 4x4's to make it solid.

How long should the 4x4's be cut too ideally?

[easdsa]

Well, let's see. Your coach is somewhat over 12,000 pounds gross weight. Figure 2000 pounds on each tire and the same on each jack. If you had a base that was 12" x 12" you would have about 14 pounds per square inch. A 4x4 is actually more like 3.5" on a side, so three of them would be 10.5" square, or a little over 18 psi. I'd be tempted get two 8' 4x4 treated posts and cut each of them into nine 10.5" lengths. That would give you a cube 10.5" on a side and shouldn't put too much weight on the base layer. You could even cut some 1x4s to 10.5" and screw them to the ends of the three 4x4s that form a layer so that you could handle one layer at a time instead of messing with individual pieces.

[grashley]

Originally Posted by unitlink

So I'm wanting to create some cribbing for our 5th Wheel since our drive slopes downward a bit. The legs have to be extended pretty far and I think I would feel better if I had some cribbing to place underneath.

The OP was asking about a sloped drive.

I suggest you take a 2 foot long level to the drive. Place it on the drive, under a jack, running the long direction of the RV. With one end on the ground, measure the height of the other end when level. Assuming 6" over 2 foot, you have a drop of 3" per foot.

Take a 2X4 one foot long and mark it for a diagonal cut, 0" at one end and 3" at the other end. Cut along the line. Make several of these. Put together with the cut edge on the driveway, the top should be level. Several nailed / glued / screwed together will make a solid, level base for your cribbing. If the drop is greater than 3 ½", use wider lumber.

I would suggest the cribbing height be about level with your tires, so the jacks are extended about the same distance they would be on level ground, assuming this is low enough to comfortably unhitch from the truck.

Use treated lumber and treat the cut edge to slow rotting and make them last longer

[Dogpatch]

Originally Posted by unitlink

So looking at those examples, doing a 3x3 would be ideal for RV's correct?
In that case it would like I would use 4x4's and go about 3 to 4 levels high with the base being 4 4x4's to make it solid.

How long should the 4x4's be cut too ideally?

You need to be able to hook up and unhook your 5th wheel so you can't really get much more blocking than would be allowed by the distance to ground from the leg fully retracted while hitched.

In my case, that's about 8". I use (2) pieces of rail road tie cut at 10" each and use one on each side. I just use leveling Jacks from there. I also use the "sizzor" expandable chocks between the dual tires for extra stability when parked.

If you have to extend more than a comfortable amount of Jack, I'd be looking for a different place to park.