Retaining Wall

[Mo2]

 

 

 

Hello there. I am planning retaining wall in my backyard, having slope of approx 600mm from the lowest point to the desired height of Alfresco Floor. 

The retaining wall will be U shaped 13.2m x 4.8m x4.8  

=> Question is H4 sleepers along with  timber stumps are suitable for this project

OR

I should use the concrete sleepers here with galvanised posts?

(The ground will be levelled afterwards assuming the wall should be sturdy to withhold 8-10 cubic meter of soil)

I want longevity but when it comes to using the concrete sleepers It wont be easy to tapper the sleepers ☹️

Looking forward for the valuable feedback

[JacobZ]

Hi @Mo2,

Thank you for your question about installing a retaining wall structure in your backyard.

While retaining walls under 1m in height don't typically require council approval, due to the large size and volume of soil being retained, I'd suggest it is worthwhile reaching out to your local council for advice before deciding on a method. It is worth a quick phone call to ensure your plans are in line with what they require.

If longevity is key, which it certainly should be, I'd suggest using reinforced concrete sleepers, such as those from Ridgi alongside the corresponding galvanised posts. This is for a few simple reasons, the concrete won't rot or bend, galvanised steel doesn't rust if the galvanisation is kept intact, and they are stronger materials than timber.

There is no need to taper the sleepers, and I would advise against it regardless of whether you use timber or concrete. It's a bit of manual labour, but it is much easier to just dig out a trench for the sleeper to sit in. Once everything is backfilled, you'll never know.

The next thing to consider is drainage. This is because any water within the soil will add to the weight pressing on the wall. This is known as hydrostatic pressure. You'll want to ensure drainage gravel and agi pipe are installed along the back edge of the retaining wall, particularly at the bottom of the slope.  If you have a stormwater outlet in your yard, the agi pipe should be connected to it by a plumber.

Allow me to tag @Nailbag and @Dave-1 to see if they have any helpful advice.

It looks like a great project and I'm excited to hear your thoughts on the above.

Jacob

[Dave-1]

Afternoon @Mo2 

That area will look pretty nice  

I will throw in a gabion retaining wall instead of a timber or concrete one The Gabion wall allows water through it and is very easy to build. You can also buy pre made baskets from Bunnings 

They come in a range of sizes but are also very easy to make them yourself. Check out my bookmarks if you would like to see some examples

Timber retaining wall, prob the next Id choose, digging holes for the posts, if you are going with 600mm high then 1200mm deep is what Id be thinking. Also having the spacing no further then say 1200mm appart will give the life of your wall the longest chance. Drainage is something you will need to factor in. 

Concrete sleepers will last the longest, tho drainage would really have to be configured into it.

One thing that you may want to consider is teh height of the level area compared to your fence, you may end up having to factor in some privacy screen of some kind. Id suggest to mark on your fence how high the new area will be, then grab a ladder and stand at that height A step down from your patio could be worthwhile as well as not needing so many resources?

Dave