RV Trip Planning Discussions

Go Back   iRV2 Forums > MOTORHOME FORUMS > Class A Motorhome Discussions
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
Thread Tools Search this Thread Display Modes
Old 07-16-2019, 06:14 PM   #1
Join Date: Dec 2018
Posts: 37
Is Four Inches of Concrete Enough?

I am in the process of obtaining bids for a concrete floor in an new garage that will house at 39 foot class A diesel pusher with no tag axle. The manufacturer of the motorhome says the front axle GAWR is 14,320 pounds and the rear axle GAWR is 24,000 pounds. The GVWR is 38,200 pounds. I can not find anything on the manufacturer's web site that states what the unloaded vehicle weight is. Since the coach is not in my possession yet I can not take it to a weigh station.

With the above information do you think four inches of concrete with rebar is sufficient, if not, how thick? I am looking for answers from people who have built their own garage, or who had it built for them, with the above approximate weights.

skitcharoo is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 07-16-2019, 06:22 PM   #2
Senior Member
Nohurry's Avatar
Join Date: Aug 2018
Location: Wa state
Posts: 121
4” should be plenty, especially re-bar reinforced. Having said that though, not all concrete is created equal and can be mixed for different uses. If your getting bids from a reputable contractor, and you tell him what you intend it for, he should guarantee his work to that standard.

2007 National RV, Sea Breeze 1321, Ford F53,
Followed by a 2013 Wrangler JK Moab edition
Nohurry is offline   Reply With Quote
Old 07-16-2019, 06:24 PM   #3
Senior Member
asuperheat's Avatar
Join Date: Apr 2012
Posts: 226
I would pour at least 6". Mine is 8" and seems to be holding up well. I had a 30,000 lb pusher. I have not weighed the one i have now but it is probably 42k ish.
2015 Tour 42QD
asuperheat is online now   Reply With Quote
Old 07-16-2019, 06:26 PM   #4
Senior Member
palehorse89's Avatar
Newmar Owners Club
Join Date: Oct 2009
Posts: 8,687
All my garage and driveway were formed with 2x6's for a 5-1/2" pour. 2 x 4 for 3-1/2" sidewalks. I would go thicker.
2000 Newmar MADP 4060, 350ISC, Spartan MM, IFS 2011 Jeep JK, M&G Braking, 2014 MTI 27' Hog Hauler, Wireless brake control, 2006Ultra & 1989 Springer
palehorse89 is online now   Reply With Quote
Old 07-16-2019, 06:31 PM   #5
Senior Member
Join Date: Jul 2018
Posts: 1,035
Every situation is a little different; some of those differences make for a bigger total difference. What works for me, in my locale, may be unsuitable for you in your locale.

In dealing with contractors I've found it best to set my own specifications, developed in conjunction with appropriate professionals, and that way I'm getting "apples to apples" bids and have some proof of performance requirements to determine contract fulfillment.

If you know the size of the tires and the approximate weight of the coach you can figure out the PSI load on the tire "footprint". The point loading on the slab is more important than the weight averaged over the slab area.

Grade preparation, soil load bearing and stability, etc also factor into the decision about reinforcement and thickness, as well as picking the concrete blend itself. Not rocket surgery but you need local input. My guess is that with sufficient reinforcement and good prep, 4 *might* be enough, but I'm only guessing.
2005 Four Winds Majestic 23A
ďTo the world you may be one person; but to one person you may be the world.Ē - Dr Suess
Solo_RV_Guy is offline   Reply With Quote
Old 07-16-2019, 06:31 PM   #6
Senior Member
texoz's Avatar
Join Date: Aug 2017
Posts: 115
26000 lbs of motor home and I have a pad 6Ē with rebar. About to built a carport that will have the same but also perimeter and crossbeams.
texoz is offline   Reply With Quote
Old 07-16-2019, 06:39 PM   #7
Join Date: Jun 2013
Posts: 54
5" of 4500 PSI and you will be good to go.
murphy55378 is offline   Reply With Quote
Old 07-16-2019, 06:45 PM   #8
Junior Member
Camp Dog's Avatar
Join Date: Jul 2019
Location: louisiana,usa
Posts: 18
I agree that the sub-base has got a lot to do with it, 4" ok on good hard ground with rebar and a small footer around edges. Down here in the swamp I would probably do 6".
2005 Winnibago Itasca spirit 24 V10
Camp Dog is online now   Reply With Quote
Old 07-16-2019, 06:50 PM   #9
Join Date: Mar 2019
Location: Oliver, BC
Posts: 33
Concrete is very strong in compression, but weak in shear strength. Rebar placement and ground prep under the concrete are most important. You could have a very thick slab but if it gets undermined or if there is very little rebar or if the rebar is laying on the ground (and not in the slab) it will crack and move.

With that said, ensure your slab is poured over a compacted base. Rebar grids 16" O.C. approx 1.5" from the bottom of the slab. 5.5" thick should be plenty.
2003 GMC Sierra 1500hd, 6.0L, 4.10
2016 Winnebago Minnie 2451 bhs
crazymason is offline   Reply With Quote
Old 07-16-2019, 06:52 PM   #10
Senior Member
Unicorn Driver's Avatar

Join Date: Jan 2017
Posts: 5,619
Just did a pad for my 23000lb coach. Contractor poured 5 inches with rebar mesh.
2008 Itasca Latitude 37g UFO Gas pusher.
2012 Jeep Wrangler Sahara JKU.
Unicorn Driver is online now   Reply With Quote
Old 07-16-2019, 06:52 PM   #11
Senior Member
grindstone01's Avatar
Join Date: Oct 2017
Posts: 3,093
Forget the rebar, go with fiberglass filler. The cement company can mix the fiberglass in with the concrete and save the rebar hassle. The fiberglass will leave little fiber hairs sticking up that will eventually wear down and disappear with time. I would go at least 5", better too thick than not enough. Make sure you have a good gravel base and drain tiles along the edge with a drain basket in the center unless the floor is sloped. Also put in seams or have the concrete cut every 6' to relieve the stress and control any cracks that might show up later. Your concrete contractor should have plenty of suggestions. Tip - Someone might suggest to broom the surface to make it nonslip. Don't go for that, you want a finished smooth surface, easier to sweep clean and to move a floor jack around on.
I built my pole barn 20 years ago using 5" fiberglass. Now my son parks his semi in the barn and the floor is still holding up good. You never know what the future use for the barn might be.
2018 Chevy DRW
2008 Carriage Cameo, F34CK3
Full Time since 2012
grindstone01 is offline   Reply With Quote
Old 07-16-2019, 07:02 PM   #12
Senior Member
Join Date: Feb 2015
Posts: 1,127
4 inches would be the least I would go. Most recommend 5 or 6 inches. I would do 5 1/2 just to be sure.
2015 Itasca Ellipse 42QD
2017 Jeep Wrangler Rubicon Hard Rock
2011 Harley Davidson CVO Street Glide
TXTiger is online now   Reply With Quote
Old 07-16-2019, 07:03 PM   #13
Senior Member
AudiDudi's Avatar
Join Date: Jun 2017
Location: Western Montana
Posts: 557
X2 on fiber mixed in the concrete. I used pig wire on both the pours I have done along with fiber. Got a few small cracks over 20 yrs but no separation.
Mike & JoAnne
Montana Summer / Arizona Winter
'16 Prism 24G / '02 HitchHiker 38 LKTG
AudiDudi is offline   Reply With Quote
Old 07-16-2019, 07:14 PM   #14
Senior Member
153stars's Avatar
Join Date: Mar 2019
Location: Braidwood Il.
Posts: 671
The fiberglass reinforced with mesh hash held up at work very well. Doesn't finish out quite as fast or well as plain.My son in law has has a sweet stainless drain basin 18"x24" ish in his big garage with 1" grate. It has like a reverse trap made of 4" pvc .Not exactly sure of idea. It in heated floor. Maybe to stop breeze when filled a bit or stop accidental oil spill from flowing out I know it's sweet setup. Can definitely bucket wash car or truck in there .

95 Monaco Crown Royale
M11 400hp, 4060 trans.
Aquahot, Generac Guardian7.5k
153stars is offline   Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Good thing it's not 6 inches longer.... BarbRN Winnebago Industries Owner's Forum 19 01-19-2011 05:54 PM
Driver Side of Coach Leaning 2 to 3 Inches Larry B. Alpine Coach Owner's Forum 6 05-10-2010 11:01 PM
Enough is Enough! It's gone! loranimal Monaco Owner's Forum 13 09-15-2007 08:36 PM
OK Howie, enough is enough!!! C.CARNEY Toy Haulers Discussion 19 06-19-2005 07:30 PM

» Featured Campgrounds

Reviews provided by

Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 06:56 AM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.