Parking your heavy trailer on concrete

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Boonieman

Boonieman

Well-known member
Joined
Feb 19, 2017
Posts
382
Location
Meade County, Ky
Years ago my dad had a concrete/asphalt business. A lot of times we would pour concrete in someone's back yard for a garage or patio, which meant backing a concrete truck back onto an existing drive. That is a lot of weigh per square inch where those tires are resting on the concrete. To prevent the concrete from cracking, we would lay down boards for the truck to back up on, which spread out the weight from those heavy trucks. We never cracked anyone's drive using this method. We just built a pole barn with a concrete floor, and I have the toy hauler wheels parked on 2x8's to prevent too much weight from being placed on a small surface area. Concrete cracks, fact of life, it's gonna do it. But this is one method to allow it to crack where you want it to. (Expansion joints, etc)  Lots of people here probably already know this, but for those that don't I'm just passing along what I have learned.
 
True...but I don't think the trailer tires are putting anywhere near the weight of a concrete truck onto the concrete pad. Farmers park farm machinery on concrete pads all the time and they don't usually put boards down. Sounds like overkill to me.
 
Thanks for the reminder Boonieman. Something I knew but hadn't thought about in this circumstance. I suppose the thickness of the concrete could be minimized while still getting good long use from it as well.
Bob
 
Thing is, there are different grades of concrete, based on psi strength. Normal residential concrete can be as little as 2000 psi, while commercial is much higher, all the way up to bridge strength. I was just offering a tip because one of my neighbors saw the boards and asked, and it made me think about it. I am totally into overkill.  ?
 
WFD said:
True...but I don't think the trailer tires are putting anywhere near the weight of a concrete truck onto the concrete pad. Farmers park farm machinery on concrete pads all the time and they don't usually put boards down. Sounds like overkill to me.
Click to expand...
But many motorhomes will. So it depends on, not only the driveway construction, but the RV, too.
 
For what it is worth; I think it is a good idea not only for the weight issue, but for the fact that to my understanding concrete holds moisture for it's entire life time.
I have an earthern floor in my pole barn, but still leave the trailer parked on wood, just for that reason.

jack L
 
And yet there are thousands of firehouses across the country that don't seem to have a problem.
 
Yep. I was once a fireman. 5000 psi rated concrete 8 inches thick with reinforcement wire vs normal homeowner drives of 2000-2500 psi 4 inches thick, no wire.  Anyway, not going to argue. Just trying to help a normal RV owner to hopefully prevent them from cracking their driveway. Cheers.
 
Your trailer tires are probably inflated to 60-80 PSI.  Even a large motorhome seldom runs much more than 100 PSI.  That's how much pressure the tires put on whatever surface is supporting them, and that's way below the rating of even 2000 PSI concrete, no?

Divide the weight on the tire by the inflation pressure in PSI and you'll get the contact area in square inches.  Subtract a little fudge factor for the sidewall stiffness.  For example, a tire carrying 3000 lbs at 60 PSI will have a contact area of approx. 50 square inches.  Each square inch will be supporting 60 lbs.

Of more concern is the surface the concrete is poured on, it's compressibility and the resulting span loading of the concrete under the tires.  Park over a weak spot that lets the concrete sag downward under a load and you may exceed the concrete's span strength, creating a crack.

If the concrete was poured over a properly compacted base, you shouldn't have any problem.

 
Yes Lou, I believe your math is very close to correct. And if the concrete was poured correctly, with a good base, it would probably be ok. But a lot of people didn't see when their concrete was poured, and there are a few shady contractors (or homeowners doing it themselves) I have seen pour concrete straight on dirt or other poor construction techniques, or poor drainage gets under the concrete softening the base. Usually when concrete cracks due to weight, it isn't directly where the load is setting. It usually cracks next to the load applied as the concrete tries to "bend". Near the edges or at corners of expansion joints are particularly vulnerable, as those spots tend to have less support underneath. And sometimes the darn stuff cracks no matter what.
 
Damn! why do people ALWAYS think that contractors are out to screw them?  Yes, some try, fortunately they get weeded out pretty quickly
40 years in the business and I NEVER cut corners,  I know the men and women I worked with and around were just as honest... by the way, here in central New Jersey concrete sidewalks are spec'ed at 4" @ 3500 psi and only carry an occasional fat guy like me... That said, garage floors and car driveways are spec'ed at 6" min and 4500 psi, more than enough to carry the weight of an RV.
I apologize for the rant but I'm sick and tired of all the comments about crooked contractors... just like EVERYONE knows someone killed on a motorcycle... Hey, the checks in the mail!

Keith
 
I think in another Post but:

Ask around. Everyone knows someone who's had concreate work done. Ask Who did it and are they happy with it. Yul learn right Away quik.. who to contact, and who to stay away from.

We had a Contractor.. Friend of a Friend.. poor in a 6" deep, 30'L x 10'W driveway, connected to a 45'L x 25'W pad, on the side of the S & B.. all with [Composite Strands] in the mix.

12 years old now.. expansion joints every 12 feet, minor (to be expected) cracking, but none under the FW tire area. No settling.

(FWIW, they did the ground prep on Friday. I trenched & stubbed Sewer/Water and 30 amp electric on Sat & Sun, they did the base, and pored on Monday) (planning ?)

Life is good.  :) :) 
 
When we built our house, we asked around like you said and hired the recommended local contractor for a 30 ft. X 40 ft. garage slab.

He put in a single expansion groove in the middle of the 40 ft. side and said the slab would form a hairline crack there as the concrete cured.  He was right.  There have been no other cracks since.

We asked for a level slab.  When we wetted it down during the cure, the water evaporated in a perfect sheet with no pooling at all.

He also did the slab for the local rental center's building and got the same results.  There are good ones out there.
 
I certainly didn't mean to disparage contractors as a whole, after all, I've been one of them. And the topic of discussion wasn't even about that. But I do feel bad if someone took it that way. Probably like Camping World, who gets bashed regularly on here, as well as some RV manufacturers, or Car dealers. It must hurt to be judged by the sins of a few. It has to be disheartening to get lumped in with the fast buck folks that hurt the reputations of the ones that try to do it right. But anyway, I will stick to my $10 boards under my tires, if nothing else to make me feel better.....even if I'm kidding myself. And for those that respond to my posts, even if I don't particularly agree, I totally respect your opinions and appreciate you taking the time out of your day to respond.

Boonieman
 
Thanks Boonieman! Good advice in general to think about what you are doing re: concrete. Nothing more "exciting" than having concrete buckle unexpectedly and ruin your day, for sure.
 
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