Side walk replacement

Discussion in 'Bricks, Masonry and Concrete' started by Mtowner, Nov 2, 2010.

  1. Nov 2, 2010 #1

    Mtowner

    Mtowner

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    The side walk pad has sunk where Istep up to the cement pad for the front stoop. It is a rather new home and I've been told by neighbors that the area has been filled in to make grade when the hous was built. It is only one pad of the 50' side walk and I would like to remove the one pad, fill to level, and repour.
    My 2 part Question:
    How do you mix the cement (what is the receipe) and How do you finish concrete. It is a sidewalk pad , 3'X6', 4" thick..
    Any help is welcome
     
  2. Nov 2, 2010 #2

    DrHicks

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    I'll assume you've never done any concrete work before...

    That said, the BEST thing you could do is find out if you have a friend, neighbor and/or relative who you could pay to help you. This isn't a difficult job, but must be done correctly or the end result will be worse than when you started. So...


    To remove the sunken slab, you'll need to pry up a corner (with a long heavy bar & wood blocks) and break it apart with a sledge hammer. Get if off the ground or you won't be able to break it.

    Build forms, using 2x4s with "form stakes." Match one end of the forms to the pre-existing sidewalk. Make sure they're level from the stoop to the old sidewalk, but have one side slightly lower than the other (a perfectly flat & level sidewalk doesn't drain water). If it were my project, I'd put an "expansion joint" on the stoop end of the new sidewalk slab.

    Pour some heavy-grade gravel into where you'll pour your pad. Level it out and tamp it down good. Without this base, your new pad will sink just like the old one.

    For mixing the concrete, I'd suggest renting a small portable mixer like this. It will cost a little ($50 maybe), but will be worth it. http://www.quikrete.com/productlines/ConcreteMix.asp Each bag will have instructions regarding how to calculate the amount needed. Pick up and extra bag or two. You can always take them back, but you do not want to run out in the middle of the job.

    Mix 1-2 bags at a time. Use your garden hose and spray in water while the mixer is running. It is hard to describe the right consistency of the concrete, without calling it a "slump test," but roughly speaking, it should be about the consistency of pudding (maybe a bit stiffer). Smooth each "dump" of concrete with a small shovel until you have all the concrete you need in the forms.

    Run a "screed board" (probably a 4' 2x4) across the forms to do the first leveling of the concrete. Fill in any low spots & re-screed. [​IMG]

    If you don't have any kind of float, and don't want to buy one, you can use a short 2x4 (maybe about 1' in length) for the next smoothing.

    After the concrete has set for a few minutes, use a hand trowel to finish the smoothing process. There is no magic to this, other than keeping the front edge of the trowel a bit higher than the back edge (not doing this will make you dig into the concrete).

    For the best finished look, you'll want to "edge" your concrete as well.


    It's kind of hard to describe, but not terribly difficult to do - assuming you take your time and carefully do things right.
     
  3. Nov 2, 2010 #3

    AlwaysOneMoreProject

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    Broom after trowelling?
     
  4. Nov 3, 2010 #4

    Mtowner

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    Should I broom the concrete after trowelling or just let it "as is" after trawelling. I really am new at this cement work and just want it to look OK
     
  5. Nov 3, 2010 #5

    AlwaysOneMoreProject

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    I wouldn't trowel it. I'd screed, float, broom and then edge. Trowelling gives concrete that really smooth finish that's like ice when wet.

    Also, I'm guessing that your walkway is light in color. You don't want to use bagged concrete for your project because it'll look awful because the bagged stuff is very dark.

    I'd just order ready-mix. It may not match perfectly but it'll look professional and the cost of bagged white cement is so high, you may only pay a very small net amount for delivery.

    I'd also build a little 2x4 form and a few bags of concrete and practice a few times to get my timing right. First time around, you'll probably over work it and you don't want to do that on the side walk.
     
  6. Nov 3, 2010 #6

    DrHicks

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    ^^ Good points. The only thing I'd disagree with - and this is just an opinion as to whether it's worth it - is ordering ReadyMix. He's needing less than 1 yard of concrete, and the ReadyMix company will almost certainly tack a "small load" fee on. It'd be nice, and convenient, but he may pay $150 or more for less than a yard of ReadyMix.

    On the other hand, it might be worth it to him.
     
  7. Nov 3, 2010 #7

    Redbirdseven

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    someone spoke above about ordering ready mix. You will not be able to order such a small amount as you will be needing for your project. Go ahead and mix up a sample from your bag mix and spread it out and let it dry to see what the color will be. If it is to dark then get some color to add to your mix to lighten it up. Try another test to see if you are close enough to match what you have in the side walk. Doing this is not hard and you will be able to match almost any thing in the future also.
     
  8. Nov 3, 2010 #8

    AlwaysOneMoreProject

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    6 cubic' means he'll need two bags of white cement, iirc. That's $30. Then, he'll need some gravel, sand and a mixer. I'm thinking talk to neighbors who might want to share the cost of ready mix. :D

    Can you dye concrete white?
     
  9. Nov 3, 2010 #9

    astin

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    The concrete bag has instructions on it. Just follow the directions and it will be very easy.
     
  10. Nov 5, 2010 #10

    DrHicks

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    Actually, you can get the pre-mixed stuff that only needs water added to it.
     
  11. Nov 5, 2010 #11

    Redbirdseven

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    I don't know about white but you sure can lighten it a lot. You can also go to any colors like green,red,brown,and so on. A local brick yard is a good place to go to and find colors you can add to the mix.
     
  12. Nov 5, 2010 #12

    itsreallyconc

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    can't get white when using grey portland,,, apron stores carry coloring powders OR, alternatively, 1 can buy universal tints from sher-wms for a small cost,,, add the color to the mix water then to the dry bagg'd mix,,, whatever color you use, remember it lightens when dry compared to the color you see when wet.

    IF you need white, you'll have to use white cement.
     
  13. Nov 5, 2010 #13

    Tangelo

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    Hello Mtowner, have you considered slab jacking the sunken piece of concrete. The process involves a hole being drilled into the sunken slab, then a limestone type grout is pumped into the cavity beneath the slab, and slowly the slab will raise up to the original height. You can check your local yellow pages for companies that do this and get several bids, it will cost you far less than replacing the slab, and it wont stand out as a new slab. Let me know what decide to go with.

    ~Angelo
     
  14. Nov 5, 2010 #14

    AlwaysOneMoreProject

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    If he's going that route, you don't think just prying up the low corner and washing sand under the slab is worth a shot?
     
  15. Nov 6, 2010 #15

    head-first

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    There is some good info in this thread that I will find handy when I do a similar task soon... I just wish I could get replies like this to questions in my threads. :confused:
     
  16. Nov 7, 2010 #16

    DrHicks

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    Whachu talkin bout, Willis?

    What threads?
     
  17. Nov 7, 2010 #17

    mudmixer

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    You do not "dye" concrete lighter.

    The color of the concrete is manly determined by the sand color and the color of the cement (raw materials).

    Dick
     
  18. Nov 7, 2010 #18

    itsreallyconc

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    mud, is that fish plaster of paris or part of the catch 'n' release school ?
     
  19. Nov 7, 2010 #19

    oldognewtrick

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    Thats his shinny new tie tack...;)
     
  20. Nov 10, 2010 #20

    head-first

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