Construction On Our New Motorhome Pad Starts Tomorrow!

[Moebius]

The pictures of the construction of our new motorhome pad we buried in an old post, so I decided to split them out into their own topic. Construction start tomorrow (7/28/2016) with excavation at 7:45am.

Picture Album

http://imgur.com/a/JBbPa

Picture #1: Tree moved to make way for the pad.
Picture #2: Lines drawn to mark excavation.

 

[Oscar Mike]

Congratulations! We are getting ready to add a steel shade structure soon...

 

[Moebius]

Congratulations! We are getting ready to add a steel shade structure soon...

Sweet! We would love one of those. We most likely don't have the room on the sides though. Having it home will be good enough for me...for now.

 

[Moebius]

I just uploaded more pictures to the album. They got the excavation done this morning and put up wood forms for the concrete pour that happens tomorrow.

We won't be able to bring Irving (our coach) home until the concrete cures after 10 days, but we are still excited! The 50 amp receptacle will be installed next Wednesday.

 

[Rene T]

We won't be able to bring Irving (our coach) home until the concrete cures after 10 days,

They say the Hoover Dam concrete is still curing because it's so thick so you may have to wait years for yours to fully cure.  :'(;D  

 

[Moebius]

They say the Hoover Dam concrete is still curing because it's so thick so you may have to wait years for yours to fully cure.  :'(;D

;D

 

[JoeFatz]

Just an FYI, I'm going to tell you that parking a monster rv on 10 day old concrete is the worst thing you can do, it may not crack (that you can see) today but you will be putting to much stress on the concrete, concrete takes 28 days to fully cure.
With the heat we have in my area this is not a good time to pour unless your committed to watering the pad for the next 3 weeks at least, this will allow the concrete to cure evenly instead of from the top to the bottom in stages, watering it or soaking it once or twice a day will make your slab a whole lot stronger.

 

[Moebius]

Just an FYI, I'm going to tell you that parking a monster rv on 10 day old concrete is the worst thing you can do, it may not crack (that you can see) today but you will be putting to much stress on the concrete, concrete takes 28 days to fully cure.
With the heat we have in my area this is not a good time to pour unless your committed to watering the pad for the next 3 weeks at least, this will allow the concrete to cure evenly instead of from the top to the bottom in stages, watering it or soaking it once or twice a day will make your slab a whole lot stronger.

I appreciate your concern and your advice. When I asked the contractor how long before we could put the coach on the pad, he said 10 days. There is going to be commercial grade fiber mesh mixed in with the concrete to make it stronger and it will be 6" thick, which is the same thickness as the right of way in this area. He said that we'd be able to walk on it shortly after it is poured, but the weight of the coach is too much.

I love getting opinions on this type of stuff and it's hard not to take it into account. However, I have gotten advice here that even contradicts the owner's manual for our coach. Who should I believe? You may be right, but that's why we have a 2 year warranty for the pad, I guess.

Since the coach is in storage, I can wait a little longer, but I am going to avoid making another storage payment if it's short of 28 days.

 

[JoeFatz]

the whole fiber thing is really a matter of opinion, I dont like it for slick slabs because of all the hairs that stick up and hinder getting a glass like finish, your pad should be a broom finish being its outside so thats not an issue.
I assume (hope) they are going to use at least 3500 psi, I also looked at the photos and noticed no expansion material against that stucco house, a lot of guys, myself included dont like the way it looks, black material, what I have done in the past is place it 1" below the finished grade so its not visible, without it probably isnt a real big issue as your basically pouring on sand and if the slab moves it can move away from the house, hopefully.
6" is good but a little overkill.
At least make sure you keep the pad hydrated for as long as possible, you will be able to walk on it late tomorrow but you'll scar it up, if you wait until saturday morning and soak it down and then put some burlap or plastic on it that will allow it to keep itself wet.
The longer you wait to park a 15000 lb+ vehicle on it the better.

 

[Moebius]

the whole fiber thing is really a matter of opinion, I dont like it for slick slabs because of all the hairs that stick up and hinder getting a glass like finish, your pad should be a broom finish being its outside so thats not an issue.
I assume (hope) they are going to use at least 3500 psi, I also looked at the photos and noticed no expansion material against that stucco house, a lot of guys, myself included dont like the way it looks, black material, what I have done in the past is place it 1" below the finished grade so its not visible, without it probably isnt a real big issue as your basically pouring on sand and if the slab moves it can move away from the house, hopefully.
6" is good but a little overkill.
At least make sure you keep the pad hydrated for as long as possible, you will be able to walk on it late tomorrow but you'll scar it up, if you wait until saturday morning and soak it down and then put some burlap or plastic on it that will allow it to keep itself wet.
The longer you wait to park a 15000 lb+ vehicle on it the better.

Yes, 3500 psi is what is being used and it will have a light broom finish. I think it's a good idea to ask about expansion material against the house, so I will ask tomorrow when they are back.

If I sounded ungrateful, I apologize. It sounds like you know a lot about this and I will take your advice about keep it wet and waiting as long as I can before parking our 22,000 lb (dry) motorhome on it.

 

[Gary RV_Wizard]

Although Florida sand is forgiving, I personally would have liked to see some rebar or mesh in that form before pouring. That's a 22,000 lb coach, 15k on the rear axle alone. All that weight rests in just 4 places, literally bending that concrete near the edges. Six inches of 3500 psi fiber is good, but that's still a lot of stress. But I've given up trying to get a concrete guy to take a conservative approach - they always say "Oh, we've done hundreds of them this way and you don't need more". Then try to find them when it cracks... But it should be ok, given that sand is firm when compressed and drains extremely well. Those two things alone go a long ways toward a solid concrete platform.

One nice thing about this place, is there is no shortage of opinions, or any lack of variety among them.  That way, somebody can always say "I told you so" later.  ;D

 

[Moebius]

Although Florida sand is forgiving, I personally would have liked to see some rebar or mesh in that form before pouring. That's a 22,000 lb coach, 15k on the rear axle alone. All that weight rests in just 4 places, literally bending that concrete near the edges. Six inches of 3500 psi fiber is good, but that's still a lot of stress. But I've given up trying to get a concrete guy to take a conservative approach - they always say "Oh, we've done hundreds of them this way and you don't need more". Then try to find them when it cracks... But it should be ok, given that sand is firm when compressed and drains extremely well. Those two things alone go a long ways toward a solid concrete platform.

One nice thing about this place, is there is no shortage of opinions, or any lack of variety among them.  That way, somebody can always say "I told you so" later.  ;D

I asked about the rebar also and since there is going to be stress on the end of the pad when pulling the coach in and out, he said that part of the pad will have rebar in it. I have also read several articles about rebar and that in certain circumstances, it actually causes the concrete to fail more frequently. It appears though, that among professionals that fiber mesh is either love or hate, so the jury is still out.

I still appreciate everyone's input, even though, at times, it gives me more stress because there are more things to think about.

 

[SargeW]

The hands down best thing you can do to make your slab as hard as possible is to cover the whole thing with plastic after it is poured and broomed.  Concrete cracking is caused by the rapid loss of the thousands of gallons of water that will naturally evaporate out of the cement in a short period of time. The plastic will force the cement to cure very slowly, and the pad actually becomes "self watering" as the water in the cement cannot evaporate as quickly.  I can promise you if you cover the whole slab for 1 week, you will have no problems driving the MH on it after 7 days.

After a 30 years of pouring cement in So. Cal, I too have a bit of experience in the pour and finish of concrete in warmer climates....

 

[Moebius]

The hands down best thing you can do to make your slab as hard as possible is to cover the whole thing with plastic after it is poured and broomed.  Concrete cracking is caused by the rapid loss of the thousands of gallons of water that will naturally evaporate out of the cement in a short period of time. The plastic will force the cement to cure very slowly, and the pad actually becomes "self watering" as the water in the cement cannot evaporate as quickly.  I can promise you if you cover the whole slab for 1 week, you will have no problems driving the MH on it after 7 days.

After a 30 years of pouring cement in So. Cal, I too have a bit of experience in the pour and finish of concrete in warmer climates....

Thanks for this Sarge. When they come to pour the concrete, I will make sure they cover it with plastic. Would the difference in humidity in Florida be a factor?

The timing is a little tough. We are headed out to camp very close to home (about 4-5 miles), so we won't be able to keep an eye on it until Sunday, but we can come home if we need to. Hopefully, they will do the pour before we head out later. Fingers crossed!

 

[SargeW]

Some guys resist using plastic, mostly because they don't want to pay to buy it. But the beauty of using it is that once the slab is covered, there is no need to have anyone there keeping it moist by watering it several times a day to slow drying.  As a matter of fact, I had one older gentleman over water his slab so badly that he washed off big holes in the surface.  Asking someone  to keep your freshly poured concrete damp is always a crap shoot, hoping that they don't over do it.  Plastic eliminates that possibility.

 

[Macrosill]

I would follow the instructions of your contractor.  You get a 2 year warranty.  If you do not follow his instructions then he can say you caused a failure if it should happen.  If it does fail then you can say you followed his instructions and he has to warranty it.

If you do not like his instructions and have faith in his knowledge then you need a new contractor.

Just my opinion.

 

[kdbgoat]

I would follow the instructions of your contractor.  You get a 2 year warranty.  If you do not follow his instructions then he can say you caused a failure if it should happen.  If it does fail then you can say you followed his instructions and he has to warranty it.

If you do not like his instructions and have faith in his knowledge then you need a new contractor.

Just my opinion.

Good suggestion. Armed with suggestions such as the plastic, etc. you could ask the contractor some intelligent questions about how to take care of it for maximum life and such.

 

[Moebius]

I would follow the instructions of your contractor.  You get a 2 year warranty.  If you do not follow his instructions then he can say you caused a failure if it should happen.  If it does fail then you can say you followed his instructions and he has to warranty it.

If you do not like his instructions and have faith in his knowledge then you need a new contractor.

Just my opinion.

That is my feeling exactly. I do trust our contractor because we have heard good things about his work. Conflicting opinions keep being brought up here by people who have done this for living, so I need to ask the questions, at least.

Our plan is to do everything we are supposed to. If a failure occurs, then we will be calling him. He has been doing work in our area for over 30 years, so I think that says something.

 

[Gary RV_Wizard]

The Florida humidity does indeed help slow the curing of the concrete, but the intense Florida sun has the opposite effect. I'm not sure how it balances out, but covering the slab is still a good idea.

I think Macrosill is right, though. Once you select the contractor, you pretty much have to go with his procedures. You can ask questions, make suggestions, and offer to pay extra for some additional measures he may not have included in his estimate, but at the end of the day, you either fire him or trust him.

 

[Corky]

I've built several garages over the years, and the one thing that was taught to me was keep the pad damp for as long as you can. To that end I used straw to shield the pad from the sun, and with a morning watering kept it damp for the day.

The last pad that I poured I followed the advice from the owner of the concrete company about the use of "whiskers". Whiskers are supposed to take the place of wire and prevent the concrete from cracking. Well out of 5 pads this one is the only one that has cracked. I won't use them again, but will continue to use the straw.

Good luck with the new addition.

Corky