Foundation for fifth Wheel as Permanent Home

[jray]

Hi There,

This is pretty urgent....

My cousin and I own a 4-acre agriculturally zoned property on the Big Island, Hawaii.

He purchased a large fifth wheel rv and it will be delivered to the completely undeveloped property on the 24th of this month (4 days from now).

Can anyone out there point me to online resources or otherwise suggest how best to permanently set the rv for use as a primary dwelling?? To be more precise, utility hook-ups are not a problem....I'm interested in knowing the best possible foundation to use.? ?That is, is a platform or concrete foundation necessary??

He and his wife will be the first to move onto the property and I will follow, so I'd like to mitigate problems for him and then go down the same path for my wife and myself.


Thank you, in advance for any help,

JRay

 

[Bob Maxwell]

Welcome to our RV community -a great place to get questions asked and enjoy meeting new RVer's.

My full-timers I know have a cement pad designed for they way they want to use it. It's especially handy in times of heavy rain. The weight can cause you to sink into wet soil, and unevenly at that. I sure a landscape service could tell you what you need for weight bearing at your specific location and maybe even put in a bis for the contract or recommend contractors.

Where are 5th wheel units made in Hawaii?

 

[jray]

Hi Bob,

Thanks for the prompt reply!

Other than cement...is there an alternative like, say, gravel that will allow us the ability to decide on a more permanent location later?

Otherwise, I'll have to get that cement pad PDQ.

The fifth wheel wasn't build in HI.
It will be shipped in from the mainland.

Best Regards,

JRay

 

[Carl L]

As Bob said, a concrete pad is probably the best. ?Have it poured by reliable contractor. ? Given the critter population of the Big Island you may well want to screen off the underside. ? A set up for a large propane tank should be in your considerations.

A 5th wheel in the Islands? ?Bob wants to know where they are built. ?I am curious about who can make a living selling them. ? ;D

 

[Tom]

Baserock from a landscape yard would work as a temporary base. Use maybe 8" and it will compact pretty good and be a decent temporary base. As Bob suggested, check with a local landscape service for recommendations specific to the soil conditions.

 

[jray]

Tom & Carl,

Thanks for this valuable insight!
And for your speedy response to my request.  ;D

Now I've got 2 options.

JRay

 

[Chet18013]

Not knowing the local soil and drainage , makes it tough to suggest anything. Having said that, why don't you do like the do here in the mainland for most mobile homes? Set  the fifth wheel up on concrete blocks, It you use enough of them and take care leveling, you should have a solid, yet easily moved foundation. I have a 12' x 55' office trailer that I mounted on concrete blocks (cinder blocks) stacked 3 high over 15 years ago and it's as solid as a house on a foundation.  The stacks of blocks are 8' apart--give or take a bit. For extra stability, you can always fill the cavities in the blocks with concrete. With the trailer up on blocks, it's easy to apply insect control around the base of each block also.

Remember, when you mount the trailer to take the wheels off and store them inside, out of the direct sunlight. This will greatly reduce the rate of oxidation of the compounds in the tire rubber.  Then you'll be less likely to have a tire problem when you want to move it in the future.

Chet

 

[Carl L]

Other than cement...is there an alternative like, say, gravel that will allow us the ability to decide on a more permanent location later?

Well, yes, pea gravel can make a good base if it the pad is cut and backfilled to a depth proper to the rock used and the soil it is in.  However, you are in Hawaii.  Your entire island is basalt, and only basalt, and a lot it is scoriacious basalt --.  How well that will work as pea gravel in your climate I suspect may be dependent on whether you are on the leeward or windward side of the island.  Check it out with your local contractors. 

 

[Gary RV_Wizard]

I wouldn't be afaid to use local stone for temporary foundation, even if temporary is a year or two. Just put down plenty of a large size stone (e.g cobblestone) to support the weight.  But if it is to be permanent, you may as well jack it up and remove axles and wheels. The tires are going to be a total loss in 5-6 years anyway ( due to drying out), even if never used.  May as well sell them while still new. Concrete blocks are the time-honored method of support "mobile" homes - use double colums at the corners and a columm somewhere in the middle of each side, about where the axles were.  And make sure the blocks have a solid foundation underneath as well, e.g. the stone as was suggested for the wheels. Something to keep them from sinking too deep in the soil and allowing drainage.  But once you take if off its wheels, there's a good chance that local building codes will dictate how it must be anchored to the ground, so check first.  If removing the axles change the status in ways you cannot tolerate, leave them on but I would suggest the blocks anyway.  If blocks aren't OK with you (or the zoning board), you could always have appropriate sized columns poured. Just get them close to the right size and do final adjustments with pressure treated wood shims. Or better yet, one of the new synthetic woods that are insect and rot proof.

Since its a fifth wheel (why a 5th wheel???), it will have "landing gear" in the front, which are adequate for fairly long term support, but I would still reinforce the front corners with blocks to take most of the weight. And keep the front up in case the front hydraulis ever fail (are we talking years here?).  Its may also be a good idea to support the king pin (the hitch under the front) to reduce vibration and the tendency to sway slightly. I don't think there will be any need to do this once the rest of the rig chassis is firmly supported, but if the trailer is standing on its wheels and front jacks you will probably want a king pin jack to firm things up. They sell specialized portable bipod or tripod jacks for this, but you can jury rig something if you plan for a permanent foundation later. The ubiquitous concrete block colum (at least double blocks, because it is tall) probably would work with a little scissor or bottle jack added at the top. See http://www.pplmotorhomes.com/parts/rv-jacks/fifth-wheel-stabilizer.htm and http://www.pplmotorhomes.com/parts/rv-jacks/fifth-wheel-jacks.htm for examples.

Does Hawaii have high winds like we do here in Florida?  If so, I would suggest metal strap tie downs to make sure it stays on whatever foundation you end up with.  Check with local building suppliers for tie downs and anchors fo rportable building (if local codes allow them at all) - if there is enough soil you may be able to use giant screws as anchors (I'm talking 10 inches wide and 4-5 fet long). But if  they say you can't have portable buildings or they have to be tied to a undergorund concrete footing, be warned to (a) be circumspect with local building officials and (b) get out of the trailer before any winds come. The last is good advice anyway.

 

[Karl]

Just wondering if PSP (Perforated Steel Plate) wouldn't be helpful in distributing the weight over a large area? Might work well over a bed of crushed stone/pea gravel/etc.