This is my first post, but spend LOTS of time reading posts on this great forum!!!
I am building a 40m retaining wall, not very high, between 0.4 to 1m high. Want it to last for a long time, and be cheapish. Planning on using 100 UC 14.8 H-Beams at 2.4m intervals, with treated pine. OK, H-Beams are not that cheap, but last long. The question is how do I get the treated pine to last long? Ideas I have are:
1) Put plastic sheeting behind sleepers before filling with pebbles and soil. Will have agi pipes coming out under each sleeper of wall at 2.4m intervals. The back of the wall is bush, so not an issue if it doesn't look to great with agi pipes. This way back of sleepers should not get wet, and should have plenty of drainage to get rid of water.
2) Possibly paint back of sleepers with that thick black waterproofing stuff. Not sure what you call it, but used it for back of besser block retaining wall once to waterproof it. Will this increase life of sleepers?
3) Another idea is to maybe place sheets of fibre cement behind sleepers before filling with pebbles and soil. Will this be a good idea, increase life of sleepers?