# How NOT to pour concrete **URL:** \ **Category:** NYSpeed Off Topic\ **Created:** [April 16, 2013, 12:00pm UTC](https://forums.speedlife.net/t/how-not-to-pour-concrete/230030 "2013-04-16T12:00:38Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![rugsr](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/rugsr/32/7474_2.png) [@rugsr](https://forums.speedlife.net/u/rugsr)\ **Post date:** [April 16, 2013, 12:00pm UTC](https://forums.speedlife.net/t/how-not-to-pour-concrete/230030/1 "2013-04-16T12:00:38Z")
I poured a pad back in the day and need one this year. Since its been a while I decided to refresh by watching youtube…lol check this one out. Right off that bat you can tell this guy isn’t good. Skip to 4:30 to see how to properly make a control joint (:tup: to the guy beeping the horn) To top it off, they leave the 2x4 in between the existing and new pad [https://youtu.be/ed6q3mkJ0xs](https://youtu.be/ed6q3mkJ0xs) ---
**Author:** ![1QIKZ](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/1qikz/32/6112_2.png) [@1QIKZ](https://forums.speedlife.net/u/1QIKZ)\ **Post date:** [April 16, 2013, 12:48pm UTC](https://forums.speedlife.net/t/how-not-to-pour-concrete/230030/2 "2013-04-16T12:48:07Z")
Pro’s use knee boards and mag floats. They also use a 2 x 4 or aluminum straight edge for control joints, or snap a string line. Should’ve used 6 x 6 wire mesh instead of rebar. Should’ve drilled pins into the edge of the existing slabs before the pour. You don’t bull float like that. Stone underneath the pad would’ve been nice. Pro’s don’t usually need the truck driver to help. All his tools looked virtually new. Seasoned pro I’m sure. ---
**Author:** ![JayS](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/jays/32/15375_2.png) [@JayS](https://forums.speedlife.net/u/JayS)\ **Post date:** [April 16, 2013, 12:53pm UTC](https://forums.speedlife.net/t/how-not-to-pour-concrete/230030/3 "2013-04-16T12:53:27Z")
Still a billion times more talent that that Korean guy building a shed. ---
**Author:** ![boardjnky4](https://avatars.discourse-cdn.com/v4/letter/b/96bed5/32.png) [@boardjnky4](https://forums.speedlife.net/u/boardjnky4)\ **Post date:** [April 16, 2013, 12:58pm UTC](https://forums.speedlife.net/t/how-not-to-pour-concrete/230030/4 "2013-04-16T12:58:47Z")
ehh, looks like it came out alright, aside from the 2x4 left in, I doubt he’ll have much issue. he certainly shouldn’t be the person GIVING the how-to advice, though. ---
**Author:** ![rugsr](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/rugsr/32/7474_2.png) [@rugsr](https://forums.speedlife.net/u/rugsr)\ **Post date:** [April 16, 2013, 1:14pm UTC](https://forums.speedlife.net/t/how-not-to-pour-concrete/230030/5 "2013-04-16T13:14:06Z")
> [@1QIKZ](#): > > Should’ve drilled pins into the edge of the existing slabs before the pour. I have heard of this before (to prevent the new pad T.O.C. from changing) but I have heard a few others saying if a new pad is pinned to and existing pad/foundation and the pad wants to move, it will beginning cracking and could break. Not sure if I totally believe this though ---
**Author:** ![Blue\_Eyed\_Devil](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/blue_eyed_devil/32/7292_2.png) [@Blue\_Eyed\_Devil](https://forums.speedlife.net/u/Blue_Eyed_Devil)\ **Post date:** [April 16, 2013, 1:27pm UTC](https://forums.speedlife.net/t/how-not-to-pour-concrete/230030/6 "2013-04-16T13:27:06Z")
Should not have used any re-bar or mesh… easier to remove when it falls apart. 🙂 ---
**Author:** ![TradersBASE](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/tradersbase/32/5321_2.png) [@TradersBASE](https://forums.speedlife.net/u/TradersBASE)\ **Post date:** [April 16, 2013, 3:05pm UTC](https://forums.speedlife.net/t/how-not-to-pour-concrete/230030/7 "2013-04-16T15:05:22Z")
> [@Blue Eyed Devil](#): > > Should not have used any re-bar or mesh… easier to remove when it falls apart. 🙂 LOL. I don’t know much about concrete work but I can’t imagine there being any reason to leave a 2x4 to rot. ---
**Author:** ![1QIKZ](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/1qikz/32/6112_2.png) [@1QIKZ](https://forums.speedlife.net/u/1QIKZ)\ **Post date:** [April 16, 2013, 3:10pm UTC](https://forums.speedlife.net/t/how-not-to-pour-concrete/230030/8 "2013-04-16T15:10:58Z")
> [@TradersBASE](#): > > LOL. I don’t know much about concrete work but I can’t imagine there being any reason to leave a 2x4 to rot. That’s exactly what will happen. Not even sure why they had it there? ---
**Author:** ![fiend540](https://avatars.discourse-cdn.com/v4/letter/f/bcef8e/32.png) [@fiend540](https://forums.speedlife.net/u/fiend540)\ **Post date:** [April 16, 2013, 3:25pm UTC](https://forums.speedlife.net/t/how-not-to-pour-concrete/230030/9 "2013-04-16T15:25:33Z")
> [@1QIKZ](#): > > Pro’s use knee boards and mag floats. > They also use a 2 x 4 or aluminum straight edge for control joints, or snap a string line. > Should’ve used 6 x 6 wire mesh instead of rebar. > Should’ve drilled pins into the edge of the existing slabs before the pour. > You don’t bull float like that. > Stone underneath the pad would’ve been nice. > Pro’s don’t usually need the truck driver to help. > > All his tools looked virtually new. Seasoned pro I’m sure. Being a driveway, I disagree with pinning it to the existing pad but the rest is pretty much spot on. Guy also sucks with his edger, bad form. ---
**Author:** ![TradersBASE](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/tradersbase/32/5321_2.png) [@TradersBASE](https://forums.speedlife.net/u/TradersBASE)\ **Post date:** [April 16, 2013, 3:32pm UTC](https://forums.speedlife.net/t/how-not-to-pour-concrete/230030/10 "2013-04-16T15:32:39Z")
> [@1QIKZ](#): > > That’s exactly what will happen. Not even sure why they had it there? Isn’t wood (or a metal form) only used to frame up new pads? I’ve seen this with sidewalks, they seem to knock the frame away once things begin to set up. Once that wood rots they should have a nice 2" gap between the pads. LOL Not that I plan on doing concrete work but what would be the proper way to space those 2 pads out? ---
**Author:** ![Blue\_Eyed\_Devil](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/blue_eyed_devil/32/7292_2.png) [@Blue\_Eyed\_Devil](https://forums.speedlife.net/u/Blue_Eyed_Devil)\ **Post date:** [April 16, 2013, 3:46pm UTC](https://forums.speedlife.net/t/how-not-to-pour-concrete/230030/11 "2013-04-16T15:46:37Z")
The 2x4 is for expansion. Duh! ---
**Author:** ![TradersBASE](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/tradersbase/32/5321_2.png) [@TradersBASE](https://forums.speedlife.net/u/TradersBASE)\ **Post date:** [April 16, 2013, 3:53pm UTC](https://forums.speedlife.net/t/how-not-to-pour-concrete/230030/12 "2013-04-16T15:53:11Z")
> [@Blue Eyed Devil](#): > > The 2x4 is for expansion. Duh! My bad, It seems to have been pressure treated lumber and water sealed prior to placing/leaving it between the pads. 😉 ---
**Author:** ![Spam16v](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/spam16v/32/5287_2.png) [@Spam16v](https://forums.speedlife.net/u/Spam16v)\ **Post date:** [April 16, 2013, 6:33pm UTC](https://forums.speedlife.net/t/how-not-to-pour-concrete/230030/13 "2013-04-16T18:33:00Z")
The 2x4 has to get wet a few times, and start to break down before it works as designed and allows expansion and contraction properly. ---
**Author:** ![rugsr](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/rugsr/32/7474_2.png) [@rugsr](https://forums.speedlife.net/u/rugsr)\ **Post date:** [April 16, 2013, 10:30pm UTC](https://forums.speedlife.net/t/how-not-to-pour-concrete/230030/14 "2013-04-16T22:30:17Z")
If any of you know where to buy these special expanding 2x4’s please PM me. I may just do an entire driveway in these specials 2x4s. On a serious note, id like to hear the truth about pinning. So why on a foundation but not a driveway ---
**Author:** ![FourEyed](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/foureyed/32/7216_2.png) [@FourEyed](https://forums.speedlife.net/u/FourEyed)\ **Post date:** [April 17, 2013, 4:46am UTC](https://forums.speedlife.net/t/how-not-to-pour-concrete/230030/15 "2013-04-17T04:46:47Z")
Actually, rebar mesh is preferred, and commonly used in commercial applications, but seems a bit overkill here. They should have used the existing concrete as the form and tossed an expansion joint in there. Standard practice is to drill dowels 2-4’ OC into the existing concrete to avoid heaving of the new slab. We do it all the time, except for old existing sidewalks because they will crack. They probably watched a how to video and became “instant experts” like everyone likes to think they are when it comes to construction. ---
**Author:** ![slo\_ride](https://avatars.discourse-cdn.com/v4/letter/s/49beb7/32.png) [@slo\_ride](https://forums.speedlife.net/u/slo_ride)\ **Post date:** [April 17, 2013, 5:27am UTC](https://forums.speedlife.net/t/how-not-to-pour-concrete/230030/16 "2013-04-17T05:27:21Z")
the main reason to pin a slab to another slab or to a foundation is to maintain the finished height of the new slab. in this case you wouldn’t want the new slab to move up or down significantly as it would create a change in elevation between new and existing. at an entry to a structure if the slab were to move up you might not be able to open the door properly. on a technical note- none of these are expansion joints…concrete doesn’t expand. they are control joints to control the development of cracking in the slab. ---
**Author:** ![rugsr](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/rugsr/32/7474_2.png) [@rugsr](https://forums.speedlife.net/u/rugsr)\ **Post date:** [April 17, 2013, 6:33am UTC](https://forums.speedlife.net/t/how-not-to-pour-concrete/230030/17 "2013-04-17T06:33:09Z")
> [@FourEyed](#): > > They should have used the existing concrete as the form and tossed an expansion joint in there agreed. BTW, what sizes holes should be drilled for pins? 1/2" re-bar so 5/8" hole? Do you put epoxy in the hole to hole the re-bar? My neighbor has this new type of expansion joint in his driveway. I guess the new ones are rubber and last longer. My old expansion joint is that paper crap material that falls apart. ---
**Author:** ![1QIKZ](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/1qikz/32/6112_2.png) [@1QIKZ](https://forums.speedlife.net/u/1QIKZ)\ **Post date:** [April 17, 2013, 6:25pm UTC](https://forums.speedlife.net/t/how-not-to-pour-concrete/230030/18 "2013-04-17T18:25:18Z")
I typically use 1/2" for 1/2". Tap the pin in the hole. Don’t typically use epoxy for shear applications (where a pin is used to combat movement of two slabs or similar application). Others may disagree.