How to pin sleepers?

[IronStan001]

I'm going to box out an area of around 7x10m using 200x75mm sleepers, single height.  100mm of these sleepers will be on or just below ground, the other 100mm will be filled with compacted crushed rock.

I plan on using https://meetjack.com.au/product/retain-it-heavy-duty-retaining-stakes/ on the joins and 1 on each of the corners.  To give a little more strength, I also intend on pinning the sleepers to the ground using 600x12mm deformed reo right through the sleeper at or about 1000mm apart.

https://imgur.com/a/EjY4muF

At the corners, they'll be screwed together with batten screws.  The flat stakes will be fixed with 12G x 50mm screws.

Would 12mm reo be sufficient enough to pin the sleepers so they're reasonably solid?

[EricL]

Hello @IronStan001 

Welcome to the Bunnings Workshop community. It's fabulous to have you join us, and thank you for sharing your question about pinning your sleepers.

Your plan sounds very well thought out, I believe that the 12mm reo bars will be sufficient to pin the sleepers in place. Since the sleepers will not be holding a great amount of weight and is half buried into the ground, it should keep its shape.

Let me call on our experienced member @Adam_W for his recommendations.

Please keep us updated with your progress, we look forward to seeing your project come together.

Eric

[Adam_W]

Hey @IronStan001 as @EricL said, it sounds like that will be more than adequate.
You may want to use bar like this as it's galvanised. That will give the rods a longer life. Normal reo tends to rust pretty quickly when it's not sealed in concrete. As only 100mm of the sleepers will be above ground then having 250mm of bar in-ground should be adequate.
You do mention that the material will be compacted. That would be my main caution. When you are compacting it can exert a lot of outward stress onto the sleepers so that's when joins can blow-out or sleepers tilt. Just watch for that as you work.

[IronStan001]

Yeah, that's my main concern as to what pressure it would put on the sleepers when I compact the crushed rock.  As much as galvanised bar would be good, I was hoping to use 600mm bar to give me 400mm in ground to mitigate any tilt from the sleepers.  Is there something I could coat non-galvanised reo with to give it some protection?

[EricL]

Hi @IronStan001 

I suggest having a look at White Knight 0.5L Cold Gal Silver Rust Guard Primer Paint. I propose putting several coats on each rod before driving them into the soil. There is also the 75mm Sleeper Peg Galvanised Steel Heavy Duty as an alternative to the reo bar.

If you need further assistance, please let us know.

Eric

[IronStan001]

I kind of can't have anything over the top of the sleepers.  The compacted crushed rock is to finish level with the sleepers, which I'll then lay some basketball court tiles on top.  The 75mm thick sleepers will give me an additional 150mm width and length in the event I get the internal dimensions of the box off by a little.  If I don't have anything over the sleepers (like the peg), then the court tiles can sit over the sleepers if need be, without obstructing the tiles.

Rather than paint the reo, Jack have 12 x 1800mm hot dipped reo that I can cut as needed.  I can spray the cut ends with primer, which works out the same (or slightly cheaper) than normal reo PLUS the cold gal paint.  Once I set the sleepers in place at their desired levels using the flat stakes, I can use a 13mm auger which should allow the 12mm reo to slip in without disturbing the sleepers too much.

[MitchellMc]

Sounds like a plan, @IronStan001. Keep us updated on your project, as it sounds like a beauty, and reach out again if you have further questions.

I can't wait to see your results.

Mitchell

[TheHandySqirrel]

Hi @EricL,

I have a question re sealing the reo. Wouldn't it be beneficial *not* to seal so that it can rust? What I learned from edging is that those stakes are meant to rust which makes them expand and thus keep edging in place much better. Wouldn't a similar reason work here? Thank you!

[MitchellMc]

Are you referring to the cut ends on the hot dipped reo or standard un-coated reo, @TheHandySqirrel?

Either way, carbon steel reo is not designed to be exposed to the elements. You'd need to decide whether the benefits of having it lock into your sleepers through the rusting process overrides the shortened lifespan due to rusting prematurely. I'd suggest that you paint the reo and if you're looking for it to lock into the sleeper, pre-drill slightly under-sized holes and drive it into the sleeper with a mini sledgehammer. Be careful not to drill the hole too small as timber will swell with moisture, and you could crack the sleepers. If you drill the hole, so the reo is a snug fit, once the timber absorbs water from the surroundings, it will lock the reo in place.

I'm sure @EricL will chime in if he has other thoughts.

Please let me know if you have any questions.

Mitchell