RV side yard concrete

[cruzinZ]

A couple of years ago we built a home and I was able to move the footprint of the foundation to one side of the lot. This left me with 5’ on the short side and 15’ on the RV side. We had a metal gate installed and currently have a 22’ ski boat, 22’ class C motorhome and PWC on the side yard.

I would like to upgrade the class C to a 40’ to 45’ class A diesel pusher. The flatwork concrete I had laid down has fiber added to the mix but no rebar or metal mesh. The ground is about 6’ of hard clay soil. I doubt that we will have an issue with subsidence. Just curious what others with similar experience have had with concrete flatwork? I’m guessing it’s about 3.5 to 4 inches thick. Found a good deal on a 38’ motorhome that aim planning on checking out next weekend. Sure would be nice to upgrade. Current class c is getting around 4.5mpg’s. Should be pretty easy to double the fuel mileage with a 32,000 to 36,000 lb rig. https://www.garagejournal.com/forum/images/smilies/hellobye.gif

 

[dcg9381]

I've got a 38' 5th wheel pulled by a 1-ton truck.
We're in Texas and sitting on solid limestone. I have 40x60 pad, it as a 24" beam all the way around and two 24" x 24" beams across the middle. Concrete is 4.5" thick elsewhere. This is with rebar.. The fiber mesh foundations aren't common here. This foundation has a few cracks (non-structural)

Smaller RV pads - I have a 15x60' attached to this structure, no mid-beam spans, just perimeter beams and rebar. No cracks.

I've always gotten 8-10mpg on 35" Class-C RVs with the Ford V10. 4.5mpg would concern me, unless you're driving mountains.

The 1-ton (diesel) truck gets 8-10 mpg towing also, our RV is about 13'-3" tall. Mileage is better if you can keep it under 65.

 

[Renegade1LI]

I would go with a 6" thick pad, with wire mats, if the ground is good I wouldn't worry about adding an aggregate base. My own drive way is 6"thick with wire on good subase,20 years later still good and I have brought some heavy equipment over it, plus parking my own 42' 5th wheel. Make sure the contractor specs a design mix similar to either the town or county DOT uses for road base. Never trust the concrete supplier, they all try and cheat if they can get away with it,especially if they know it's residential. Around here they will give you bankrun if you don't ask for blue stone.

 

[rburke65]

Your concrete is good for 3-4,000# PSI. Your tire ‘foot print’ area, times the number of tires on the RV will give you the area placed onto your concrete. Weight of RV divided by total tire patch area, will give you weight on your concrete. You’ll be fine. I’m sure someone will corr3ct me if I have fuzzy math.

 

[Renegade1LI]

Your concrete is good for 3-4,000# PSI. Your tire ‘foot print’ area, times the number of tires on the RV will give you the area placed onto your concrete. Weight of RV divided by total tire patch area, will give you weight on your concrete. You’ll be fine. I’m sure someone will corr3ct me if I have fuzzy math.

That's not quite how it works, psi is just the compressive strength, you could have two inches of 4000psi and it will break fairly easily, you need a certain mass to spread the load. Most H-20 precast tops are 8" thick, just did a bus garage, similar weight as a class A, 8" thick with#5 rebar 12" oc. I am not a engineer, but I pour a lot of concrete in nyc for the mta, sca,dep so I see a lot of different designs and mixes. Typically,sidewalks are 4", driveways 6" with 8" aprons and most h-20 slabs on q deck are 8". Almost all slab in grade requires a minimum 6" compacted aggregate base.

 

[Sumboodie]

I've got a 38' 5th wheel pulled by a 1-ton truck.
We're in Texas and sitting on solid limestone. I have 40x60 pad, it as a 24" beam all the way around and two 24" x 24" beams across the middle. Concrete is 4.5" thick elsewhere. This is with rebar.. The fiber mesh foundations aren't common here. This foundation has a few cracks (non-structural)

Smaller RV pads - I have a 15x60' attached to this structure, no mid-beam spans, just perimeter beams and rebar. No cracks.

I've always gotten 8-10mpg on 35" Class-C RVs with the Ford V10. 4.5mpg would concern me, unless you're driving mountains.

The 1-ton (diesel) truck gets 8-10 mpg towing also, our RV is about 13'-3" tall. Mileage is better if you can keep it under 65.

A 24"x24" beam? Why would you stick that in a slab?

 

[Firebrick43]

A 24"x24" beam? Why would you stick that in a slab?

The concrete is formed/ reinforced in a beam section. Its not a steel beam placed into the concrete.

This is done typically in areas with expansive clay soils such as texas.

A diesel pusher heavily loaded can get quite heavy. I probably would reinforce the wheel areas of the pad quite heavy with #4 on 12" centers but the center area could be less so to save on material. There is no reason that 4" with a good sub base of compacted stone couldn't support the weight.

As for fuel economy, my wifes grandfather had a 2001 winnebaggo with an 8.1 gm v8 in it. It was the largest gas engine model(37' if i remember correctly) on 22.5" tires with 3 slide outs. It averaged about 9mpg over the 120,000 miles he and grandma put on it. It would get 11 on the flats but they lived in california and went to arizona many times which means mountains.

The previous monoco with a 454 only got 4.5 mpg and was nutless in comparison.

 

[cruzinZ]

I've always gotten 8-10mpg on 35" Class-C RVs with the Ford V10. 4.5mpg would concern me, unless you're driving mountains.

The 1-ton (diesel) truck gets 8-10 mpg towing also, our RV is about 13'-3" tall. Mileage is better if you can keep it under 65.

I’ve herd that 7-10MPG’s is pretty common with the newer units. Our current MH is a 22’ class C. Chevy 350 with a 3 speed transmission. Our 4.6MPG’s was mostly flat ground between 60-62mph and some hills. Our regular campground that we go to is 42miles away up an 11% grade.

 

[dcg9381]

A 24"x24" beam? Why would you stick that in a slab?

That's what I mean. Concrete beams are "under" the concrete pad. Basically we framed a "table" with cross beams and then pour a top.

 

[dcg9381]

I’ve herd that 7-10MPG’s is pretty common with the newer units. Our current MH is a 22’ class C. Chevy 350 with a 3 speed transmission. Our 4.6MPG’s was mostly flat ground between 60-62mph and some hills. Our regular campground that we go to is 42miles away up an 11% grade.

Ahh.. Carb / TBI... I get it. With a 3 speed. That's hurtful!

 

[38Chevy454]

I guess I look at it like this: use what you have for the new higher loading motorhome. If it is not up to the task, later you have to remove the old concrete and redo it with thicker and reinforced. Or you can do the demo and new concrete now. Why not just use what you have for now and then make decisions later once you know better if the current is up to the task?

 

[firebirdparts]

I agree. Step 1 is to do absolutely nothing. Destroying concrete to prevent it being damaged is crazy.

Step 2 is wait for it to break. You might wait forever.

 

[Sumboodie]

The concrete is formed/ reinforced in a beam section. Its not a steel beam placed into the concrete.

This is done typically in areas with expansive clay soils such as texas.

A diesel pusher heavily loaded can get quite heavy. I probably would reinforce the wheel areas of the pad quite heavy with #4 on 12" centers but the center area could be less so to save on material. There is no reason that 4" with a good sub base of compacted stone couldn't support the weight.

As for fuel economy, my wifes grandfather had a 2001 winnebaggo with an 8.1 gm v8 in it. It was the largest gas engine model(37' if i remember correctly) on 22.5" tires with 3 slide outs. It averaged about 9mpg over the 120,000 miles he and grandma put on it. It would get 11 on the flats but they lived in california and went to arizona many times which means mountains.

The previous monoco with a 454 only got 4.5 mpg and was nutless in comparison.

Ahhhhhh, derr!

We just call that a footer edge. Like my patio is 6" with a 12-26" footer. Built it like that we the idea I could incorporate it into a garage expansion if needed.

 

[Sumboodie]

Single digit MPG doesn't sound crazy. My Dodge truck with 6.7L diesel gets 10-12mpg empty.

Truck is maybe 8500lbs or so, never weighed it. The bed floor is 3 sheets of 1/4" plate.
Was discouraged as my square body with a gazillion miles averages 8-9mpg and weighs about 17,000 when loaded.

The couple diesel pickups I had with tin can beds averaged about 15mpg.

 

[Firebrick43]

Ahhhhhh, derr!

We just call that a footer edge. Like my patio is 6" with a 12-26" footer. Built it like that we the idea I could incorporate it into a garage expansion if needed.

Well, not quite, these might run across the center or several across the middle, basically as if the slab was suspended. The advantage is that the ground itself is the form work unlike a suspended slab.

The Idea is that the whole slab is truely monolithic no mater what happens underneath it.

If you have just footer edges it assumes that the center area of the slab will stay dry, thawed out, and stable.

 

[Falcon67]

I did a 12x12 perimeter with a 12x12 down the middle and 3 across on my 24x40 slab. Hasn't moved in 10 years.

>Single digit MPG doesn't sound crazy. My Dodge truck with 6.7L diesel gets 10-12mpg empty.

The 1993 F-350 460 gets 9.9 dead empty and about 5 with 12,000 lbs on it at 60 MPH. It only weighs 5800 lbs. The new F-350 7.3L gas gets around 12~13 and over 7 pulling 12,500 over non-flat territory @ 70. Think it weighs about 6800 - haven't put the combo on the scales yet. Old vs new has a huge difference.

I see Class As in driveways all over the place here. If it's a standard type driveway slab it's very likely just fine. The drag strip sees a lot of big toters, Class As with stacker trailers and such, I think they used 8" in the pit area.

 

[Bluearmflames]

I’m originally from Clovis. If the soil hasn’t been disturbed I wouldn’t worry about it to much. The ground is probably about as hard as the concrete over it. Keep water from migrating around the slab and you will most likely be fine.

 

[mx500]

just bought a 40' 2004 diesel pusher with a 330hp cat. drove it from mich, to florida over spring break. got 10mpg through georgia and tenn, doing 70-75.. (havent filled it up since we got home to check the mpg, but prob same since less hills. closer i got to home (mi) the closer it got to 80mph..lol.