What timber to use for retaining wall?

[ososbg]

Hi all,

First time poster here and sorry if it's a naive question.

I want to build a retaining wall and also to be a raised garden bed at the same time. I've two sides in my backyard I want to use both of them, one side is 15m and the other side is 14m, the retaining wall height is about 500-600mm.

My question is, what timber I should be using for this:

1.8m H4 Treated Pine Sleeper 200 x 75mm.

2.4m H4 Treated Pine Sleeper 200 x 75mm

1.8m H4 Treated Pine Sleeper 200 x 50mm

2.4m H4 Treated Pine Sleeper 200 x 50mm

Thanks in advance

[ososbg]

Hi @EricL , thanks so much for your reply. Can you please explain to me what does um means in the plastic sheets ? and also, how to fix the sheet to the wall, shall I use stapler gun or normal nails. Sorry for asking so many questions and I appreciate your help and the rest of the team.

[EricL]

Hello @ososbg 

The term 200um refers to the thickness of the plastic 200 microns. The higher the number the thicker the plastic.

In regards to fixing the plastic to the sleeper, it's best to use a staple gun so that it will not create a big hole in the plastic. I also suggest covering the staples with clear sticky tape. But once the soil gets put in it will hold the plastic in place. 

If you need further assistance, please let us know.

Eric

[ososbg]

Thanks @EricL , this is super helpful.