How to build a retaining wall with 3m sleepers?

[Yangaz]

Hi all,

I am working on a small area in my yard (3.2m x 3.8m) to install a stepped retaining wall to level out surfaces at both levels. Refer to the pictures below. I plan to use the retain-it metal posts to hold in the 3 x (50mm x 150mm) timber sleepers making the wall 450mm high, the pieces are 3m in length.

1. Are 50mm thick sleepers too thin to hold back the soil? should I go to 75mm?

2. Should I be cutting the 3m lengths into two 1.5m lengths and have a middle post, concerned the 3m sleepers with no middle post may bow over time? I will install an ag line to drain water buildup in front of the retaining wall to the open area as I don't have a connection to stormwater for this small area.

Thank You

[Yangaz]

Thanks, Jacob for the quick response. I think we will go for the Iceberg decorative stones, is there anything I should put on top of the dirt to avoid grass and weed and also loose dirt?

[JacobZ]

Hi @Yangaz,

You can lay some weed control mat down and secure it in place with weed mat pins before covering the area with your decorative stones.

This will help keep the dirt in place and act as a barrier to prevent the weeds growing through.

Let me know if you have any other questions.

Jacob

[Yangaz]

Hi,

Here is the latest update.

The bottom level has been completed using the ki-carma iceberg stones, which turned out to be a nice warm colour to offset the grey-rendered walls of the house.

Now, working on the top layer. We decided to also put the same stones on the top level of the area. Can I use coarse sand to level the surface before applying a weed mat and then the stones on top? something like this? https://www.bunnings.com.au/ki-carma-20kg-coarse-landscape-sand_p3460054?srsltid=AfmBOoptFUEwR97cQ9y...

Would you recommend putting in another timber sleeper on the top level where I've placed the sleeper in the picture so that the dirt and rocks don't run off?

https://www.bunnings.com.au/ki-carma-20kg-16-25mm-iceberg-decorative-stones_p3460044

[JacobZ]

Hi @Yangaz,

It looks like things are coming along nicely. Thank you for the update.

If you're planning to level and place more stones in the top area, I would definitely add another timber sleeper across the front to keep the stones in place. Ideally, you would have this sleeper run level with your other retaining wall, so some digging will be required.

The other thing I notice is that your sleeper posts sit slightly above the top sleeper. Was there a reason for this, or was it a slight oversight? 

If you wanted to cut them so they sit flush with the top of your sleepers, you could use an angle grinder with some cut off discs to cut them flush with the top of the sleepers. If you were to do this, please ensure you wear gloves, eye protection, hearing protection, long work clothes and a mask.

Let me know what you think and if you have any further questions or updates, please don't hesitate to post them.

Jacob

[Yangaz]

Hey @JacobZ 

Here is a more recent photo. Yes, I did find the posts being higher quite annoying so I replaced the top tier sleeper with a wider 200mm sleeper to fit nicely. 

In regards to the top-level surface, can I use ki-carma coarse sand to act as a leveling surface before I put down the weed mat and then the rocks on top?

Would you also use posts for the timber sleeper for the front to keep the stones in place?

[JacobZ]

Hi @Yangaz,

That looks even better, congratulations on the progress.

Yes, that would be a great way to level the area before adding weed mat and stones.

For the single layer sleeper, I would add a Jack 75 x 450mm End Post concreted in at either end of the opening for the sleepers to sit in. This will give you a good strong barrier that will keep everything in place.

Please keep us updated with your progress, I'm very excited to see the finished product.

Jacob