Sleeper walls & concrete idea

Sleeper (or landscape timber) walls are easy to build but eventually need replacing due to rot. I have this idea to concrete into the hole dug out with post hole digger a reinforced cement beam/post. The wooden sleepers are then attached to the inground cement post. After 20 years you just replace the wooden sleepers and leave the post. If there are any engineers out there, I would appreciate your calculations on the design of the post. I was thinking 200*120mm with two vertical N25 deformed steel bars up each side with 50mm cover. Underground depth is one and half times above ground. Max 800mm aboveground. Pedestrian loading only. Slight pitch. Concrete compaction in forms done by vibrator from hire shop.

Basically is this worth the effort? Will it work? Or should I just use really thick sleepers?

Can you use Galvinised I beams and slip the sleeper in between. They won't go anywhere and the sleeper could be replaced.

I think sleepers would last longer that 20 years ... do you expect to be in that house when you are 60?

Hi Phil
I have just built my 2400mm x 4800mm two a 200x75 sleeper high vegie garden. I have painted them with a bitumen type paint, mainly to protect my kids from touching the treated pine, but should also prolong the durability. Just used sleepers concreted into the ground in the corners and along the side to aid strength. So hopefully last me a whilst!!
Cheers
Mcblurter

"Landscape timber" (timber treated to H4 standard or above) should last 40 - 50 years. I think that concrete pillars are over-kill.

An important consideration is installing drainage behind the wall to prevent water pooling. Here's an example:
http://tinyurl.com/2hpevt

I have no connection with the company referred to in the above link (a Google search will produce similar examples of Australian companies that supply landscape timber).

HTH

Mike

See here my friend:

http://www.ozlogs.com.au/

I think the galvanised UC posts are the best way too, for longevity, aesthetics, and space. These posts are concreted in, and your sleepers just slot in. The whole sits flush so you don't have to allow for in front of your wall and have it looking tidier IMO.

The longevity of the wall also depends on the quality behind it, too. Drainage needs to be installed at the base, with aggregate filled 3/4 of the way or more to the top to eliminate pressure from waterlogged soil pressing against the timber, or rotting it.