Posted: 30/08/2013 at 19:13
On price: http://www.gabionbasketsuk.com/
Quite expensive, apparently. What I *think* is the way to use them is to dig the bank back, level the base below the bottom level, put in a line of them and fill them up, fill behind them to level, put the next row on top, set slightly back, fill those, fill behind them to level et cetera until you reach the lawn level. It's probably a good idea to tie them down so the soil can't push them over each other with the passage of time and topple the lot, unlikely though that sounds.
Tree roots may well make this more difficult, as they tend to be thick, tough and near the surface, but the further from the nearest tree you start, the less harm you'll do the tree by just cutting through them and ripping them out.
I'd suggest building up high enough to level the lawn, so it can't flow over the top of them. This will leave you with a "dead" part across the bottom. Thinking of it as a path may be easiest.
To put a wall on it, you could probably just concrete the base onto the filled gabion. To put up a fence, I'd actually cut holes in the top mesh of the gabions and put the posts into them, pouring concrete in around the post bases, or put those ground spike things in through holes in the mesh, concrete those in and then stand fence posts in them (so you can pull out rotten fence posts years from now and put in fresh ones very easily).
I'm sure a wall of filled gabions would be a quite effective noise blocker, but that's a very thick wall and rather expensive. It would probably be cheaper to build it out of breezeblocks or bricks. You could also try a wooden fence with wide slats on both sides and narrow gaps between the slats on alternating sides, so wind can leak through but there are no lines of sight. It won't be as effective, but it looks less ... well, concrete.
Just my opinion, not a professional assessment, but you can probably build just about anything on top of them if it doesn't require a crane. An image search seems to confirm this.
Not sure about the plants. At a guess, anything that likes "well-drained soil", if you cover the things in gravel and then soil, should cope. You may find yourself having to top up with compost, sand and/or topsoil as it leaks down through the stones, though. There's probably a rule about soil depth relative to final height.
The washing ... umm ... well, shorten the hedges on the south side? Shorten the hedges all around to improve ventilation? Engineer's approach: build your retaining wall down both sides of the garden, finishing with a 1m gabion-top path well above ground level, mount pulleys on the outer wall on top of this, string the line around them and hang your laundry higher off the ground! Of course, this requires one person to attach clothes at each pulley so you can use both sides of the line at once. It wouldn't have to be a military fortified wall, really. You could just have a little Disney Princess-style tower at each side and string the laundry between them.