Sleepers - Raised beds and retaining walls

[karlrob]

when building raised beds and retaining walls I have been using 4" thick posts concreted into the ground to attach the sleepers to using 6 inch countersunk screws, they seem really solid when done but I'm concerned about the posts rotting !

what measures can I take to prevent this in years to come ?

[rab1]

use treated timber. but it will rot eventually

[darrenba]

Use Oak sleepers and concrete them in?

[local patios and driveway]

you may get as little as 10 years from a 4x4 post. ive had a call back a few months ago at this age. not happy.

[local patios and driveway]

forgot to say, darren that looks great

[lutonlagerlout]

i spoke at length to a structural engineer about "timber retaining walls"
the main points to consider are
1 height over 1 m it should really be designed

2 drainage,a land drain and weepholes are a must on retaining structures,its the build up of water that causes most to fail

3 any post should be at least 600mm into the ground and also potentially anchored at the rear

4 old railway sleepers are apparently very strong,new softwood timber much less so,I had a 3by 3 post supporting a tree in my garden and it rotted through after 5 years
LLL

[henpecked]

You can get good quality hardwood sleepers from the net for about £25 a throw.