Pouring Concrete Walk

[jwstewar]

I'm getting ready to pour a walk to go from the deck to the driveway. It'll be 4'X16'. I'm going to mix & pour myself. I've already got the sand, gravel, & concrete but I'm getting ready to go buy lumber for forms. I know it needs to be 6" thick. With the 2" of sand in the bottom should I buy 2X6's and put them in place and then my sand, plastic, & then finally the cement. 2X4's and put the sand down then the forms? Or should I go with a 1X material? Help!!!!!!
Jim

 

[Gary_in_Indiana]

If you want a true 4" formed edge to your walk a standard 2" x 4" board won't give it to you. Those are the old nominal dimensions. The finished board you buy is smaller in each dimension. I just thought you ought to consider that. Good luck with your project. /w3tcompact/icons/smile.gif

 

[jwstewar]

Yeah, I had thought about that and knew that I could only get the 3 1/2 that way. I ended up going with the 2X6 - was cheaper than going with the 1X material. This will give me a couple inches of sand and then I know that I can get my true 4" walk. Not sure when they were saying 4" if they meant 2X4 height or a true 4". I going with the true 4" were rather error on the side of caution than have a walk that is all cracked. As this is my first attempt at finished concrete work I would like for it to look decent. Thank you for your reply.

Has the judge came out to your property yet?

 

[patrickg]

Many flatwork contractors use finished 2x4 when pouring 4 inch sidewalks (3 1/2 inches, actually). If you don't mind the expense, 4 inches is great and less likely to crack.. I recommend that you use wire mesh and or rebar, use a tool (less than $10) to make your "expansion joints" or whatever they are called in your area. These purposely weaken the concrete at regular intervals so that hopefully if it cracks it will be in these "control joints" (another popular name). All concrete guys I have talked to say concrete will crack it is just a matter of where and when so engineer for it. Another good option and not too constly is to order at least 3500 psi mix AND get the fiber additive. The fibers help reduce cracking and help keep any hair line cracks, hairlines. Keep the job cool, pouring in a cooler part of the day, misting so it never dries out, covering to shade it or whatever. If it is allowed to get too hot it will crack more and not be as strong and crack resistant as it would have been if cured more slowly.

Oh yeah, compact the substrate if it is not already highly compacted and compact the sand too before pouring. A lot of folks don't do any of the things I mentioned and a few probably get away with it. Some folks could play Russian Roulette and not get killed but that doesn't make it a good idea. NOt much cost in doing a better than average job but if you want a higher probability of long term success, ask a knowlegeable concrete guy if any of these things are bad ideas or will weaken your job. Many will say it is overkill and different ones will say different ones of the ideas aren't needed but can't tell you that any of them won't make for a stronger longer lasting result.

Patrick

 

[chim]

Around here, it's common to see contractors use 2x4's. They usually form and pour on top of a compacted crushed stone base that extends well beyond the finished edge of the concrete. One thing that could happen if you place the form and add the sand, then pour is the sand will most likely fall out from beneath the concrete at the edges when you strip the forms.

Mebbe someone already mentioned it, but when you stake the forms, keep the top of the stakes below the top of the form - makes screeding a lot easier.................chim

 

[wroughtn_harv]

You've got some good tips. Do remember your expansion joints and one other thing. Keep in mind you need to have the cove tool for rounding the edge. You can get a cheapy at the box store but do get one cheap or not.

That rounded corner protects the edges from breaking and chipping.

As for the expansion joints. I had a sidewalk crack at my house. One of these old boys stood there chewing on his toothpick and with no emotion said, "that concrete will tell you where you should have put in an expansion joint." Gotta hate them know it all old pharts./w3tcompact/icons/laugh.gif

 

[Gary_in_Indiana]

<font color=blue>"Has the judge came out to your property yet?"</font color=blue>

I think you have me confused with someone else, possibly MDNY

 

[jwstewar]

I guess I did. You are the one trying to foreclose on the property which you hold the mortgage. Too many threads here at TBN to keep up. Too much for my small mind to keep track of. Sorry for the confusion, I'm just curious how both of these situations turn out.

 

[jwstewar]

I did pick up one of the little cheapy edgers while I was at Lowe's yesterday. I already had the tool for doing the expansion joints not sure why I had bought that and not the edger. Not sure what I was thinking way back when I bought that and the trowels several years ago. I guess I'll plead ignorance.

<font color=blue>"Gotta hate them know it all old pharts"</font color=blue> But the good thing is I do that at work too. "You really don't want to run this new system on Windows 98, we need to go to 2000." Now all of a sudden a year later, we are installing 2000 and they are all coming to me saying yeah we should've listen to you, it would've have been much easier & cheaper. And I'm only 30, wow that hurts I remember when I was 21 and saying the same thing. Guess I'll wonder off and sulk about getting old /w3tcompact/icons/laugh.gif
Jim

 

[jwstewar]

Great tips. Hadn't thought about packing the sand that I'm using for the base. I guess I thought the sand would already be settled. I'll have to figure out a way be it a roller or a vibrator. As this is just a small walk from the deck to the driveway there isn't enough concrete to have delivered we are only talking around a yard so I'm just mixing it myself. Will probably aim for the 3500 psi rating though. Never know when you'll have to back over the walk with the truck be it on purpose or accident as it is right beside the driveway.

 

[jwstewar]

Hadn't thought about the sand falling out from under the concrete. Wishing I had gone with the 2X4s now. The good news is I'm single handedly responsible for ending the drought here in Southern Ohio. My nice flat bed that I was digging out yesterday (hard as rocks from lack of rain) now looks like the bottom of a swamp. Guess I won't pour until next weekend. Now what can I do with the 2500 lbs of sand sitting on the truck and how do I get that trailer unhooked loaded down as well.......guess I'll unhook the trailer with a jack and unload the truck to the trailer even though I know that would be over 2 tons (it is only a little 5X8 cheapy from Lowes for hauling lawn mowers rated to haul a ton) but I won't move it just park it right beside the swamp err future walk.

 

[Green_in_MI]

I would go for the higher strength mix. 3500 psi won't get it done because that spec is an ideal number if you do everything else correctly. ie, water ratio, sand and gravel mix with the proper gradation, and good mixing mechanics. Portland cement can be purchased with a higher (5000 psi) rating

To get your sand properly compacted simply wet it lightly and tamp with a heavy flat object. You will need to a little experimentation and practice to get the right moisture content for full compaction. Too much moisture and you will see water squeezed out and too little you will see sand squeezed(pop) out. It's not rocket science you will recognize good compaction as you tamp on it.

Also the 3500psi is measured as a compressive strength and not a bending or flexural strength. That number would be about a third of the rated strength. Concrete fails in bending not compression. Its a small area so go for the higher strength mix especially if you ever think a heavy truck will drive over it. The 3500 mix might do if you use steel mesh approximately 1 inch above the bottom of the walk.

Don't overwork the surface because the fine material is rise to the top and become dusty over time.

 

[patrickg]

You can tamp stuff with a 4x4 pumped verticaly if you don't have access to automation. Regarding driving onto a walk... If it is located where it can be driven on or over, it will be, eventually.

Patrick

 

[Green_in_MI]

Pay no attention to my comment about Portland cement and psi rating. I was thinking of premixed bags I have seen at the big box stores. Everything else being equal, such as good aggregate and mixing etc, concrete strength is achieved mostly through water to cement ratios. Your bag of portland cement should have the mix ratios for desired strength on it. Also an item some people do not pay attention to is that the quality of water is important. If it is not clean and close to potable you probably will not get the good curing you want for strength. For your case an extra bag or so per yard will get you better results cheap.

 

[jwstewar]

OK guys, I finally got the sidewalk poured this past Saturday. What do ya think for my first attempt at finished concrete work?/w3tcompact/icons/cool.gif Only previous experience with concrete is dumping Quikrete in holes for fence posts or whatever. I did have a couple little problems that you'll see in some of the other pictures I'll post. It set up a little bit too much when I was trying to do the expansion joints, they got a little dry and didn't "smooth" out as quite as nice as I would have like and left little holes/rough spots. I zoomed in on these in the next few pictures. Is this something I should worry about? Should I put a concrete sealer on it? A mortor type mix? Obviously I don't want to bust this thing out and start over, but nor do I wants patches on a new sidewalk or have it cracking/crumbling come the first freeze.

Again thanks to all of you for the replies to help me tackle this.

Jim

 

[jwstewar]

A closeup.

 

[jwstewar]

Another close-up of an expansion joint.

 

[jwstewar]

A little bit farther view away, but straight on shot of a joint.

 

[jwstewar]

Another shot of one of my character flaws.

 

[jwstewar]

And yet another.