Retaining walls - Drainage

My favorite way of building things is to point and say "please put that there".

Unfortunately, with the sheer amount of retaining wall I need, my budget just won't allow that. I'm planning on using the interlocking stacking blocks.

So, I need to do as much as possible myself, then "borrow" teenage boys for the heavy work.

Does anyone have a link (or can you explain how) to the process for drainage behind retaining walls? I know you have to do something behind them, so that water doesn't just back up... but I don't know what.

I have a southern slope, 5 acres of it, and I'd like to terrace it with retaining walls - not the enitre thing, of course, but the area I've got my eye on will take two levels.

Everything I do seems to be over-planned, but this is something that I won't be able to re-do if it's not right and it's (for me) a big project.

How high are the retaining walls going to be? If they're too tall, then it's probably best left for the pros. Most places if the walls are going to be over 3' tall, you need to get permits to do the work, and in that case I'd at least have a pro draw up the plans for the wall even if you decide to do the work yourself. And the taller the walls, the more important the drainage is

As far as drainage, I have retaining walls, and what they did was put plastic drain pipe all along behind the wall, then put in drains every so many feet along the wall which allows water to go down into the drainage pipe which is eventually routed down to the bottom of the hill. I think you can also fill in the space right behind the retaining wall with gravel, this will allow water to drain down to the bottom of the wall rather than building up pressure behind it. If you were building a solid wall, you'd also need to incorporate weep holes into it to allow water to drain, but I think there's enough space between the landscape blocks that water can escape if it needs to.

Here are some links on building retaining walls. There are also plenty of books you can buy that give step by step instructions for building them, so you might check Amazon or your local library too.
http://www.rd.com/content/openContent.do?contentId=18258
http://www.thisoldhouse.com/toh/article/0,,219681,00.html
http://www.hometime.com/Howto/projects/landgardn/land_6.htm
http://www.ext.colostate.edu/ptlk/1118.html

Thanks!

I will be staying at or under 3 feet. Any higher requires permits, and, quite honestly, I am afraid of going too high by myself.

If your walls aren't too tall and you're really on a budget, have you considered using pressure treated wood instead? It won't last forever, but it's considerably cheaper than the landscape blocks. And it's much quicker to build and not as heavy, so you won't need as much help from the teenagers.

I've thought about wood, but I don't want to have to re-do in 15 or 20 years, and I am not planning on moving, ever.

I'd rather take my time and spend a little more and have it last. The way the land lays, I can do a bit at a time.

OK, makes sense to do the landscape block then. I ended up going with wood because I liked the look and I figure I'll have more money years from now when it needs to be replaced (if I'm even still in this house) so I figured I'd rather save money. But as something permanent the blocks will definitely last longer!

You didn't mention what type of soil you have. If you have fast draining soil and are going to bring in similar type soil as filler, you might not even need drainage.

We are going to redo our retaining wall which is made of treated wood.
It was infested with termites.
One of the reasons I do not like wood.
We are going to use stone ourselves also.
We are not going to do it till probably later this year, but hopefully when we start we will post some pictures here and or blog it to show the tears and joys of doing it ourselves.
Good luck,
Anita

I have decomposing granite. As in - where I do not want to plant anything, it's already decomposed and whereever I start to dig, it's still solid rock.

It does drain quickly, but if there's a LOT of rain I still get standing puddles.

The stacking blocks are expensive and I want to do this only once, and correctly.....

The "This Old House" link, above, has great detailed instructions for drainage. It doesn't look very difficult either.