Retaining walls

RKBJR

RKBJR

Well-Known Member
Joined
Mar 21, 2005
Location
Roxboro, NC
Does anyone have experience building retaining walls with the interlocking blocks you get at landscape supply stores? I need to build a wall that will be 4 feet tall on one end and tapers down to the ground, about 16 feet long.

The main two questions I have are what type of base I need and how to cut the blocks in half.

I'm assuming that I can build it one a dirt base as long as it's smooth and level. I'll need to cut a few blocks so I can stagger them, and the tall end will be against the house. I don't know if a hammer and chisel will cut them without crumbling them.

Here are the blocks I'm looking at using:
http://www.lowes.com/lowes/lkn?action=productDetail&productId=12233-215-110601211&lpage=none
 
we just finished a stagger retaining wall/loading dock that's 300' long and 8' tall.

We used a quickie saw (14") to cut the block, plate tamp, jumping jack tamp, lotta shovels, gravel, deadmen posts with 1/4" cables and two weeks of back wrecking work.

each block weighed 35 lbs
 
I think 4' is the cutoff... so you should be fine for not getting an engineered design/stamp...

I havent looked at building a retaining wall in awhile but here's basically what I would do:

1. Foundation (Important IMO)... I'd excavate maybe 24" below grade and come back in with a 6" gravel fill layer and really pack/level it well...

2. Build your wall

3. While going up I would put in a 4-6" drainage layer (washed stone not ABC,etc.) behind the wall to help disipate any water buildup... Depending on how long you're going to go either (1) add some weep holes just above base grade... or (2) add in a perferated pipe at the base behind the wall in the drain layer to gravity drain the water.


I'm sure there's much better write-ups online BUT if you're parking on top of the wall... or it's close to your home, etc... I'd do a little more research, may need to tie it back, etc..
 
During my college years, i built these walls during the summer, only we used the large blocks, around 12" long, 8" high, 80lbs each. You would put 2 nylon pins in each block, and the next course would sit on the pins below it. A good level base is a must. The base was excavated, pea-stone and tamped stone dust on top of that. The level was checked constantly. The longer your wall, the easier it is to spot it getting un-level. i remember many time removing a course or two to get that bubble between the lines...grrr.
I can't remeber the height, IIRC every 4 courses or 4ft, we had to use a geomesh netting to tie the courses together. you build the bottom level on top of the netting, build 4 more high, then build roll the netting up along the backside to then 4th or 5th course above it, and start laying blocks on top of it. that was some sort of buildign code. I'm not sure but I don't think we had any permits, this was upstate NY. I'd be scared to use those little Lowes blocks higher than 2-3 feet.
Another thing you need to do allow the water to drain, relieve any pressure behind it. install a corrugated drain pipe with holes in it, in a couple of feet of stone. Separate the stone with black fabric so dirt doesnt clog the stone drain.
We used a wet saw to cut the blocks. They do make masonary blades for your standard circular saw, but the dust will kill the bearings...yeah, I did.
 
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