Railway sleeper wall

[Douglas2]

I am looking to build a relatively small retaining wall out of new treated softwood railway sleepers. It will be max 6 courses high and 5 metres long. Not knowing anything about building I would appreciate any advice on:

1) Do I need to dig out a foundation for this wall - if so how deep?
2) How do I bed in and secure the first course - I was thinking of concreting in 100mmx100m fence posts every 100cm behind the wall and using them as fixed points to secure to.
3) I was then going to use timber fixings to screw each sucessive course to the one below - is this the best things to do?
4) Do I need to consider some sort of dampproof membrane behind the wall? Also, do I ned to leave gaps in the wall to release water pressure?

Thanks

 

[Thermo]

we do these on a regular basis. we use the following method:-

concrete in vertical sleepers, in the same way you would fence posts, getting them all plumbed up on a couple of string lines. we rarely put more than a dry mix bed along the base for a foundation, just to level up the sleepers.

timberlock the horizontal sleepers to the vertical ones. make sure the horizontal ones overlap and timberlock these into each other as the rows go up.

with regards the drainage it depends on what type of soil you are on, but on free draining soil, its not an issue.

dont use a damp proof membrane, it will hold moisture against the wood.

dont use old sleepers, use new machined ones. nice and square, easy to work with.

 

[TheTownCryer]

Why wouldn't you use a waterproof membrane behind a 1m retaining wall that is holding soil?

 

[WabbitPoo]

Because you should be draining it properly anyway. ie perforated pipe in some form of gravel.