Watch This Video To Learn More About Using or Not Using Rebar For Concrete Driveway
Вставка
- Опубліковано 20 жов 2020
- www.homebuildingandrepairs.co... Click on this link to learn more about concrete driveways, building decks and patios. Here's a somewhat simple explanation about whether or not you should use rebar throughout the entire driveway or possibly sections of the driveway or whether or not you should use it at all. Keep in mind that there are plenty of other building materials you can use and construction methods.
- Навчання та стиль
I enjoy it when smart people get on the internet. I haven't even watched it with the audio yet, looks good; I plan to learn more here.
This is a great video! It provides images and explanations to justify why connected rebar is necessary. Again, great video.
Great!!
A round of applause for you 👏 👏 👏 👏 👏 Wonderfully explained sir.
Many thanks
Thank you so much for taking the time to answer this question!
Notching is key!
You are so welcome!
Consider using Fiberglass rebar for ultimate longevity. You can also downsize the bar due to it's incredible strength.
Very informative! Thank you!!
This helped squash an argument with the wife! We are looking at getting our driveway redone. The concrete without the rebar is how our driveway looks right now! Good video!
Glad it helped.
Use fiberglass rebar, steel corrodes and swells.
@@mudslutmusic9052 have you used? Are they the same cost?
Thanks very much for this video. I''d never attempt doing a large concrete pour myself but it helps to know this information when contracting out the job and deciding who takes shortcuts. Plus, I've observed a recent subdivision where the builder did not put any reinforcement in the driveways...no wire grid, rebar, etc...they built a 64 house subdivision in less than a year and if they take shortcuts in the driveway, makes you wonder how many other subpar work was done within the walls of the house.
Rebar or no rebar, the number one thing you need to focus on when pouring flatwork is the BASE! Of course it’s faster to rush the base and add rebar, but your work won’t outlast a slab with a good base and no rebar. Focus on the base, add rebar to act as your BACK UP to if the base fails down the line.
Base?
@@yangmagic0703base being what's under the concrete. It could be a compacted final grade sand, road base, etc. It depends on where you are and what the municipalities require.
Thats why i use 2 inches #57 crushed concrete on top of compacted soil, then compact again after placing paver base (rock dust mixed with small stones).
Nice video, always drives me crazy to see concrete work with zero rebar
Great point!
Good explanation. Would you still recommend tying the rebar together if you were doing 5 independent slabs in a multi step walk. Each slab would have different volume by way of height.. all being the same width. I am intentionally keeping a 2” gap between them and a 6” rise separates as well
I've seen it done before, but exposed rebar could rust and over time won't be as effective. Maybe just keep them separated unless you think there will be a lot of movement from expansive soil, tree roots or something else.
@@gregvancom Sir, does not rebar, whether exposed or not, rust over time?
On the subject of tying separate pours. I'm considering doing an ~500sqft monolith slab in 10 incremental sections with bag product (portland) using a tow behind mixer. I'd plan to get it all done relatively quickly and keep the rebar and mesh covered. Meaning separate pours. Due to the grading and site access, every quote I've gotten from someone to do this location pour is ~$12k. Think that is reasonable task for one man? Mistake to tie the multiple poured sections together or a better approach? Thanks for the great content Greg.
It seems like you could do that in one day with some help from friends. If you have footing, then I've seen the footing poured on the first day and the slab poured on the next or even a few days later.
Yes, so true and not only that, how does rebar get installed, is a very good subject too. Lots of driveways are poured concrete on top of rough soil and no reinforcement at all yet zero soil preparation such as sand and gravel. Most driveways are 3.5" thick, not 4" due to the "2x4" forms they use. Some will use fence wire to reinforce the concrete however they don't use dobies to space the wire up off of the soil. Those who use rebar will also fail big and not space the rebar up from the soil so the concrete doesn't encapsulate the rebar and again, no sand and no gravel prep. It's bad enough to find a decent contractor but to spend the money and not have the right soil grade, preparations, spaced reinforcement (dobies) and so forth just says in 5 years, unless you are lucky, you will have a poor looking driveway full of cracks, gaps and uneven surfaces. There's no good in that.
Not only that…when the slab cracks at the joints rain water will corrode and swell the rebar resulting in blowouts exposing more rebar. DO NOT USE STEEL IN EXTERIOR CONCRETE.
@@mudslutmusic9052 How is that? Rebar is used in all structural concrete such as bridges and freeways etc. Control joints are engineered for that reason.
@@Garth2011 has to be coated rebar
@@mudslutmusic9052 In many cases yes and special coating for certain conditions. Not all concrete work requires coated rebar to prevent spalling.
Thanks so much for this video. This is a great lesson, I really do appreciate it.
You're very welcome!
Greg, thanks as always for another great video! Two questions if I may.
#1 I will build a 4x19 sidewalk attached to a structure. No cars would pass on it. I thought it would be 4 inches thick. What kind of metal mesh would you suggest? Some said 10 gauge mesh. What do you think?
#2 I will build 8 columns with 4 feet by 16 inches diameter sonotubes in which I've been told to put 2 vertical rebars. (Office foundations) My idea is to add footings under those. The calculation tells me to make a 32 inch diameter by 17.6 inches thicker footing. What kind of mesh would you put for this footing?
Thanks for your eventual answer.
I've seen 10 gauge used plenty of time in sidewalks. I can't tell you specifically what materials to use to reinforce your concrete, but if you're in freezing temperatures, you might check with local contractors for more information.
@@gregvancom, thank you very much!
Hello sir great video , I had a question I am getting pool deck, side walk around the house and pergola concrete pad in the back yard do I need rebar ?
I would use it.
This is a very helpful video. I am having the exact problem in my driveway. The only difference is a drain pipe that runs parallel with the concrete joints and there are drains at each joint where the corners of the concrete slabs meet. This is located immediately outside my garage doors so it is a high traffic area. I've gotten two different assessments from contractors and one suggested after demo and discovering whether there is erosion around the drain and checking the compacting, I would need 6 inches of concrete or 4 inches of concrete depending on what he finds after demo. He recommended rebar in each instance due to the high traffic area. The other contractor suggests 4 inches and using some type of concrete that has some built in material that substitutes for the rebar. Is there such a thing? I have never heard of it. From your video, it seems that I need rebar to avoid the problem I have. Cracking and slabs raising just as you have shown here.
I would ask what the substitute or additive is and do some research. I've used fiberglass additive with rebar, but not just concrete without rebar. The only thing I use with out rebar would be when building sidewalks not more than 4 feet wide.
@@gregvancomThanks for getting back to me. Does mesh sheets give similar reinforcement to the concrete slabs? My contractor is suggesting this for now for my repair.
That's a great question. I too would like to know if using a Concrete additive plus mesh sheets would help to prevent cracking.
If I wanted to build a solid slab of concrete of the same dimensions (in the video) in a freeze-thaw area (frost depth of 26") with heavy clay, and tree roots... and I didn't want to cut expansion joints, how much rebar would I need? Is it possible to create the same sort of floating slab with a basement beneath... with a clear span of 18'x18'?
Yes, you can build concrete driveways on top of basements. It will require a structural engineer.
Is mesh an option? I don’t know if it’s cheaper or better so I was wondering. My drive is 20 years old with 1” stone that is well compacted. No trees or soil erosion
Yes, as long as it's an approved material in your area. I rarely see it used in southern California.
My Brother's house has a massive amount of driveway and many of the separate slabs are lifted and/or cracked.
We discovered that there is zero reinforcement and no base preparation under the slabs when we demolished the worst one to replace it.
I'm pouring small sections to join my asphalt to my new garage and I'm using rebar but not connected to the adjoining slabs.
Need #57 crushed concrete pieces spread and compacted, then compact paver base or crushed rock with rock sand onto the #57. It's driveable at the point. Then pour right onto it. I only do concrete with that kind of base prep- much better than pouring right onto dirt.
What if I’m getting a 21x20’ slab in my back yard with no car traffic whatsoever? Should I get rebar if I’m thinking about putting a gazebo? It will be used for only light traffic and basic family gatherings
Rebar ads reinforcement, but it might not always be needed. I would use it on everything, if I can afford to.
Would it be possible to pour the foundation of a house (like a double wide) with this method? Using a harbor freight mixer? And lots and lots of bags of cement?
Yes, but an engineer might want it all poured at once.
@@gregvancom me too. But it's much cheaper by tens of thousands of dollars. So I wonder what the downsides are in terms of strength
Thanks for the info! What if you were doing the sections over time, so at the end of the slab you left the rebar extend a foot out of the slab and when you decided to make to make the next pour, you laid out the rebar and did a one foot overlap of the rebar and welded it to the existing, that should work, do you think???
You're welcome and I like your idea.
Yet another example of how water is always your main enemy in housebuilding. Everything from mold in crawlspaces to porous brick, tile showers with no red guard sealant, bad flashing on the roof, gutter misalignment, the slope preventing drainage, not sealing basements, no air gaps behind veneer exteriors, the list goes on and on. All moisture problems. Water is scary.
Definitely one of the biggest problems when it comes to home repairs and construction.
I'm building a 105.5 x184.5 sf slab that is double mat with #9 rebar at 12"oc and height of slab is 2.83 feet , so it's a continuous pour ( 8 in total ) so this video makes a lot of sense , btw my wall height is 27 feet tall , is a process water basin
Now that's a slab:)
Great video, but I have one concern: doesn't rebar bend under a certain amount of perpendicular force? Is this bending something we will need to worry about? Like if it were for a garage pad, or house
Yes, rebar can bend under extreme pressure and you might need to use more rebar and thicker concrete driveways if you think this is going to be a problem. Most of the time a 5 inch thick concrete slab with 24 inch on center number four rebar will do the job.
@@gregvancom Great. Another novice issue however: if I made say a concrete garage pad using your method, as I intend to next week, what is the likelihood that the 'entire' structure will heave as one side sinks due to for example soil erosion because the entire thing is too stiff, so instead of healthy cracking and the slight bending of rebar there would be the very dangerous heaving of the entire width of the slab like a see saw. And this can be amplified by archemedes principle if there is a fulcrum like large rocks or denser ground involved. Is this concern valid
Ya in a perfect world
Great video, Greg. My vote in where I come from (Ontario, Canada) Would be for the use of rebar all the time! With frost considerations and the weight of cars to consider, spend a little more now; rather than a great deal more, later on!!
Isn't that the truth!!! Pay me now or Pay me latter kind a thing.
Isn't metal in concrete a bad idea? Rust, expansion leads to cracking.
Few builders do rebar anymore in footings or garages. I had a hell of a time getting the builder to place rebar in my footings. He argued politely stating it isn’t necessary and I finally said it’s my home and I want two rebar on chairs. So he did it but resented it. I’ve seen so many who do not put rebar in concrete driveways either. Unbelievable today.
You know, it doesn’t always need rebar, and rebar reduces the longevity of the concrete. Over time, rebar corrodes and expands, cracking the concrete.
Really what i would like to see is a longer lasting replacement for rebar.
@@TheNativeTwofiberglass based rebar.
I made a point of having supporting beams for the concrete floor to "sit" upon.
And the floor is also tied to the outside beam along it's edge.
The slabs are dowel pinned along the remaining edges and two layers of reinforcing. @10 kilograms per square meter.
Overkill always works.
As to rebar rusting, get your depth of cover correct.
And plastic structural firber is also added to the 30 mpa concrete. At 6" thick minimum.
Why driveways are not build like foundation slabs? At least here in Florida I would imagine that would last 100x longer, almost every single driveway developed big crack due to roots and water.
How far apart is tje rebar sopost to be??
I've seen it spaced about 16 inches to 24 inches on center for concrete slabs.
If using PinkBar (owens corning fiberglass product), the tech sheets say 18" spacing it either direction for a slab between 3"-6" thick. Now with steel prices so high fiberglass looking a lot better for flat work and structural pours
Doesn't rebar rust, expand and eventually cause cracking?
It could, but if installed correctly, should reduce cracking or prevent them from expanding.
Yes, it can corrode over time.
What if you were going to do a driveway in sections but didn't want to remove all the old concrete in one shot or set up all the rebar at once? Say you removed a section of old concrete that is 1 foot bigger per side than what you want to pour. Then you rebar it with the notched forms so you will wind up with the new concrete with 1 foot long rebar sticking out the sides. Then when you do the next section you just wire more rebar on to whats sticking out to go in the next section.
The reason I ask this is because my endurance isn't what it used to be, I'm 67 and I just can't work like I used to, this would allow me to do smaller sections. In my area it's impossible to hire it out because of the demand.
👍
Glad you liked it and thanks for letting us know.
Not be a DA, but what if you only had chain fence in a pinch, could it work if you used layers of it, and used chicken coup wire humped over into arches to keep the layers separated, could that work in a pinch... JW, not trying to be a DA,
I wouldn't use any type of wire netting like chicken coop wire that could prevent the gravel in the concrete from going through it and creating a void or airspace under the chicken wire.
Thank you,
I had my driveway and sidewalks done 8 months. They didn't use rebar. I already see problems with cracks. 12 grand down the drain. If your driveway bad your better off selling the house.
Don't get down in the dumps yet, I've seen driveway like your last for decades with only a few small cracks. Let's hope for the best.
With large slabs of concrete cracks will always appear. It all depends on what they look like.
Man I'd want an update
Did they use wire mesh? Do you live in a northern or southern state?
@@Kiddro22 I live northern east coast, no wire mesh.
@@briangoodie3420A Skelton (wire mesh) should’ve been used
Can you just add a ton of rebar to make it super strength? 😂
Are you an engineer???
No
Seems to me he just has common sense, common sense is not taught in school sadly.
@@AverageJoe2020 - wait. Can you even teach common sense?? Lol. I dont know my friend.
Rebar in a 6 inch poured driveway is completely and totally unnecessary! Period!!!! The base on which the concrete is poured is the most important thing. In most cases 4 inch concrete is sufficient with proper base.
I can't argue with that. If you have the perfect base for it to sit on and you won't ever have any problems with erosion or freezing ground or tree roots or any other problems that could be created from not having any rebar then you could be correct.
Guys don’t want to use rebar cause they are lazy why not put it in? It’s not that expensive esp if your spending thousands of dollars to protect your investment
Unless you have heavy vehicles such as a 40' Class A motorhome that weighs 35,000 lbs that will be using that concrete. Then, its likely to be best going with 6".
@@Garth2011 4inch concrete driveway require mesh ? Only thing onit will be average sized car 🚗
@@evangroves7332 Yes indeed...cracks and uneven expansion joints take over after a few years and without rebar, it will simply shift and move. As this example showed, 4 square pads that are not tied together will end up as 4 pads at different surface levels over time. Concrete is not any good all by itself in the long run. Walkways and sidewalks can survive without it because they are smaller slabs and will not expand and contract from the sun and cold as larger slabs will. Most of the idea for rebar driveways is about keeping the concrete bonded together over its lifetime, not necessarily what will be on it.