Concrete Questions

EddieWalker · May 7, 2008

There's allot of studies out there on wire and rebar in concrete. In all the tests that I've read, wire is stronger then rebar when installed properly. It's just never installed properly and as a result, it fails all the time.

I don't think rebar is very expensive. It's proven to work, it's used in all commercial jobs and it's real easy to install. It cuts easy, it bends easy and it lays out easy. I had my wife do it on our house, and she said it was fun.

Saying all that, my parking pad is just concrete dumped on the ground and smoothed out. No forms, no prepwork, just five yards of free concrete that I had five minutes to accept and decide what to do with. In places, it might be 6 inches thick, in others, it's half that. In three years, it has one crack across the middle. That's probably from driving my backhoe across it with a yard of dirt in the bucket one time too many. My backhoe weighs 14,000 pounds.

If I had the money, I'd do it Dargo's way. In the end, it's probably allot cheaper in the long term. I have no doubt that he will never have any problems with it and he'll never have to spend another dime on it. That's worth allot!!!!

Eddie

ampsucker · May 8, 2008

yes, that's an important point about cure time and keeping it wet. my understanding is the cure time for concrete to reach it's ultimate hardness is 29 days. i've had the best luck with applications where i've kept it wet as much of that time as possible. just a garden hose and some plastic sheeting, trash bags, whatever. you can spray it every couple of days and it will stay damp under plastic. also very important not to let it freeze during the cure period if possible. when i've kept it wet for as along as i can, i've not had cracking, sparring, peeling or any other types of failures.

i realize you've about talked yourself into going with white rock after all this talk. i've used white rock a lot myself. it packs pretty well and such. but, as far as moving implements around, some of them heavy, you'll never have the ease you will if you go with a flat surface like concrete. if i was just parking my truck or tractor (something with big wheels and a motor) white rock would be fine. if you need to do fine adjustments to hook up heavy things with little wheels, concrete will be better.

i'll also suggest sinking some j-hooks into the concrete surface at various points so you can tie or chain down heavy implements if you have kids or pets. i'm planning to do this on a lean-to i'm putting a floor in this summer. i figure a chain or two holding the hoe or loader bucket might prevent a nasty accident when the kids are old enough to be playing places they shouldn't.

amp

johnnydel29 · May 9, 2008

My dad has been doing concrete work for nearly 40 years, and growing up, this what I did during my time off from school (since elementry school).

A lot of good advice here, but also a lot of advice that is a little over kill. If you want to do this job yourself to save some cash, your best bet is to pay a mason cash on the side to help you out. Just do exactly what he tells you. Otherwise, when that truck pulls up and you are scrambling and wasting time, your more than likely to annoy that driver. Especially w/ the cost of everything being so high, time is money and they may end up charging you more if it takes a longer than usual, especially if you put the driver behind schedule.

As for site prep:

1. Key is a good base - compacted gravel is fine. Make sure the base is nice and level.

2. Wire mesh is all you need. Mesh needs to propped up so the concrete can flow underneath it and in ends up between the slab, you can use stones or pieces of bricks. Re-bar is only necessary if you are planning to tie into a building or peir.

3. 4" of concrete is all you need, unless you are planning on driving extremely heavy equipment on it on a regular basis.

4. No need for a vapor barier. Vapor barrier is only needed for basement slabs to keep the moisture out. No need for a garage type slab.

5. When dry, you will need to score the slab w/ a concrete saw b/c it will eventually crack/ Scoring it will allow the cracks to form in the groove of the saw cut. For a square slab and even cross will be fine.

6. No need for expansion joints. The slab has four open sides to expand. If it were up against a house foundation or other structure than an expansion join would be necessary.

Footings are a good idea, but forms will work also. When using forms, the base needs to be done right. A lot of good compacted gravel.

Again, I would find someone w/ some experience doing this, otherwise this project can turn into a nightmare. Concrete can be very tricky, temperature an humidy can play a big role with how smoothly things go, especially when finishing.

Tom_H · May 9, 2008

I have worked concrete pours about 5 times and here is what I am sure of.

It is physically some of the hardest work I have ever done. It is like doing 3-a-days at football camp in pre-season.

It takes considerable skill, way more than I have. My appreciation for the people who build things with concrete went up immeasurably.

Remesh is hard to keep at the correct depth if you don't know what you're doing (like me).

Keeping the pour moist (after it sets up) really does make a difference with curing and cracking.

The experienced people commenting here have a lot of good advice.

If you do go ahead with the white stone, here's something you might keep in the back of your mind. Every so often, you might see an asphalt crew nearby doing a neighbor's driveway. If so, you might stop in and ask the foreman or contractor how much it would cost you to do a small pad inside your pole barn. Since he already is in your neighborhood with all the equipment, you might catch him on a day when he has time to come by and do a small pad on just a portion of the floor of your barn. This would give you a small area where you could keep some of your implements on dollies. Asphalt doesn't have to be as thick as concrete, and you'd not be using it as foundation material. Also, by catching the crew nearby, you'd possibly avoid any minimum job price the contractor has. With this small pad, you could back the rear of the tractor up and not even put the weight of the tractor on the pad, easily roll and align the needed implement on its dolly up to the 3ph, and there you go. You might be able to get sealer from the home center and seal it yourself if he doesn't have sealer on hand (sealer is optional). Anyways, just a thought.

sandman2234 · May 9, 2008

Dispite most concrete laborers opinions, Slackdaddy is right. Keep the hose away from the pour until the concrete is preset.(about 4 hours) I would also be careful with the vibrator, as they will harm air entranment if the concrete is over vibrated.
David from jax

Redbug · May 9, 2008

I've learned a lot from this thread about concrete. Sooner or later I will wind up doing about the same thing as George with a pole building out in the woods.

For George, I would say to get on with building your barn and worry about the cement/floor, later on. Take your time and don't get in too big of a rush. Mistakes are made when you don't take the time to think things out. With your barn up, you will have a place that is dry and fairly secure. That's the main priority. Later on, you all can tackle the floor and do it sections if you have to. It probably does not have to be Olympic standards...

N80 · May 9, 2008

I'm starting tomorrow morning. I don't know what I'm doing but I am very methodical about it.

I designed this thing myself after looking at lots of designs and plans. In some places it is probably 'over engineered' but that's okay. This is a very simple structure and I've written out step by step instructions for myself.

My only doubts are about how much diagonal bracing I need between the posts. They certainly add rigidity but they sure do get in the way. I think I'll be able to get a feel for this as it goes up.

Redbug · May 9, 2008

And George...take pics! We wanna see the project evolve. That's how we learn, also.

jdmar · May 10, 2008

With all this concrete knowledge here...can I ask a question? I have an 8" block fondation for a barn being done. Is it worth "core filling" this? The shortest part is only 20-24 inches above ground but the other side is 24" above my barn floor but about 4-5 feet above the outside ground. If I do not need to core fill it I would like to fill with insulation. ANy suggestions...every bid I got gave me varied answers.

Thanks
Peter

EddieWalker · May 10, 2008

jdmar said:
With all this concrete knowledge here...can I ask a question? I have an 8" block fondation for a barn being done. Is it worth "core filling" this? The shortest part is only 20-24 inches above ground but the other side is 24" above my barn floor but about 4-5 feet above the outside ground. If I do not need to core fill it I would like to fill with insulation. ANy suggestions...every bid I got gave me varied answers.

Thanks
Peter

Peter,

Your question cannot be answered because there are way too many variables. Things like loads, type of costruction, weather and your local code regulations.

There are allot of things that are considered standard in building. Pouring a cement pad is pertty basic, but when you read all the different views and advice in just something as simple as this, you begin to realize how much location has to play in building just about anything.

You can get a few ideas to consider on websites like this, but the only place you can get an accurate answer is going to be from your builder, inspector and engineers.

If you don't like the answers you get, we might be able to come up with a few things that might help, but those would only be suggestions that you could use to do your own research.

Eddie