# Forum Home Renovation Concreting  concrete sleepers- cast my own or buy ?

## breakerboy2000

i am doing a retaining wall 600mm high, and will need about 12 sleepers, (I will be doing another retaining wall down the track) I am wondering if it would be more cost effective if I just make my own vs buying pre made ones,
they are pretty expensive and heavy and delivery is $150-$200 unless i collect my self. 
I know I wont get the warranty/engineering etc if I make myself but its not tall so im not that bothered with that, I am just wondering, if there are any special additives for the mix or techniques for casting concrete sleepers? 
I have read a lot into GFRC for counter tops - but I haven't seen any mention of that for sleepers, it just seems like you would need a nice consistent 40mpa mix with 3x 12mm reo bars I believe is standard, and give a vibrate once in the mould? just not sure if the mix should be really dry so you have to actually press it by hand in the mould like counter tops, or a bit more wet  
my plan would be to make 12 moulds from regular 35x75 timber, giving me a 200x75 thick sleeper, I would use a service like concrete taxi to avoid all the mess with mixing and cleanup, and i'd concrete in my steel uprights in the same time while he is there.  
any suggestions/ opinions would be great!    
thank you.

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## ringtail

I'm embarking on a similar thing at the moment but with pavers for my farm road. I have about 500 to make so I'm making molds and having a go. Concrete taxi cost a bloody fortune. Either hire a mixer and get some blend delivered or just get a truck and fill your moulds up. A builder I'm working for sent .4 m3 back today after a decent slab pour. That's enough for 25 of my pavers ( or all of your sleepers at 2.4)  Just need the molds on site to take advantage of excess.

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## breakerboy2000

thanks ringtail,  
Yeah, I know they're a bit pricey, id actually use coast crete, for on the gold coast, but same same. I don't have a mixer, not sure what the price is for hire? also I haven't done a lot of concrete mixing, and im not sure i would trust my self to keep mixing consistent batches for the sleepers, i figured the coast crete would take that issue. but probbaly next time I'll give it a go if I can get my hands on a mixer. thats good that you are able to pickup the excess from your work, there is probably a lot of wastage on sites.

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## Marc

Buy a mixer second hand from ebay, cash convertors gumtree. Mixing concrete is not difficult at all, just get a piece of paper next to the mixer and write down how many buckets of sand, cement and aggregate. 
Having said that, I wouldn't even consider making cement sleepers for a retaining wall. Just get blocks ready made. you can even find them second hand, of surplus from a project. I sold a pallet of blocks not long ago for less than half the price new just to have more room for parking. Heron Retaining Wall Blocks | Building Materials | Gumtree Australia Gold Coast West - Maudsland | 1077922064

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## toooldforthis

shame ya not in Perth
these are pretty cheap I reckon CONCRETE SLABS â PANELS | Other Home & Garden | Gumtree Australia Victoria Park Area - East Victoria Park | 1074369868 
they weigh 100kg each.
$10

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## ErrolFlynn

I built a couple of 1.5m high retaining walls using concrete that didn't look too bad when finished, if not a bit industrial looking  given the height.  I used universal columns as posts with concrete between.  Its commonly done by your local council on embankments and they generally use timber between the UCs.  The only thing you need to watch out for is that concrete is heavy stuff and your shuttering should be stout enough to hold the weight while the concrete dries.  You don't want it to bow on you.  (I saw my neighbour using some ply for shuttering on a job he was doing and it couldn't hold back the weight and he now has some horrible looking 'rounded' walls.) 
With the walls I built I clamped up some railway sleepers to the UCs with big G-clamps.  Positioned some reinforcement for added strength.  And poured the concrete.  When dry I shifted the sleepers and began again.  With the sleepers being coarsely grained the concrete took on the timber's grain pattern.  You have to make sure you get rid of any air bubbles; so poke it about well as you pour, and don't have the mix too dry.  It looked quite good paricularly when painted.  You'd want to use gavanized UCs.

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## breakerboy2000

thank you for the replies. Ok you have convinced me, I might invest in a mixer. 
errolflynn, so did you cast the whole 1.5 meters high in one go? how exactly did you hold your reo in there while pouring?
 that could be an idea, but id need the forms on both sides of the h beam and i dont think i have much room on the back side of the fence. 
if i do go with the sleepers idea, I was thinking of pouring them so the bottom of the sleeper would be the front, and I would use some black plastic on the inside to help get it smooth and to prevent the wood drying the concrete. Im still not sure about ad mixtures for the concrete, I have never used them.

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## ErrolFlynn

Plastic does give a smooth finish, but you will need something very substanial to hold it in place (eg. railway sleepers). 
When I say railway sleepers I mean those things that you get from garden shops that people do use for retaining walls.  There's an irony. They are about 50mm thick - not the sort of thing you'd find on an actual railway track.  But they are tough enough not to bow under the weight.  They will warp so get your job done quickly. 
I had about 5 UC posts.  So, I couldn't do the whole height in one go.  You need to buid it up evenly over the length so that you always have a means of attaching the sleepers.  The length of the sleeper has to be longer than the distance between the posts, otherwise you won't be able to clamp anything.  You need G-clamps that are large enough to extend the width of the post and hold both sleepers to the post.  Large clamps are available.  If you pour more than one sleeper in height at the one time you will never be able to get the G-clamp in position for the adjacent section.  Tighten the clamps very very tight to ensure the sleeper sits flush with the post. 
For drainage, I cut a piece of plastic pipe to be a neat fit the tickness of he wall, taped the ends with insulation tape, and placed it between the sleepers.  When the sleepers came off the next day I poked around for it and ripped away the tape, and that will be your drain hole.  You'll have to carefully note where it is becaue you'll never see it unless you knew it was there.  The concrete will hide it.  Make sure you seal each end well with tape lest it fill with cement. 
Tie the reinforcement in position with some string or wire at the correct level.  Don't let it touch the ground on your first pour.  Once your first pour sets it will be held in positon for subsequent pours.  A little rust on the metal doesn't matter, but don't have this job take too long so it doesn't get too rusy.  Don't consider painting it, at all. 
When you remove the sleepers the next day scrub them down with a stiff scrubbing brush to remove any cement that has stuck to it.  To keep it clean for the next use. 
For the posts, you want them in alignment.  Set the end posts first then string line the others to them, that is if your wall is in a straight line.  I dug the holes by hand, deep as I could reach getting my arm in and a bit of my shoulder, without actually falling in and getting stuck!  I didn't want the posts sitting on the ground (rusting).  To help align the posts, I welded a couple of metal bars to the post, at right angles to the post, where ground level would be, and had them rest on a couple of pieces of wood.  (I suppose they could be clamped on.) That allowed the post to be adjusted precicely, forward or back and when braced with a length of timber to keep it at the right angle it was solid enough to pour the concrete and be confident it wasn't going to move.  I removed the steel bar before continuing.  If you are welding the zinc will come off.  So you'd want to do this in a position where it will be covered in concrete so that it doesn't rust.

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