Building gravity retaining wall with blocks, drainage

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Old 03-03-11, 02:57 PM
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Building gravity retaining wall with blocks, drainage

I'm looking to build a 4' retaining wall using stackable blocks. My question is drainage. It can drain, but it would be on the sides, and if you put the drain tile in there, do you need to pitch it at all? My biggest fear is water just sitting in there and not getting out. Also.. where do you pitch the water to? I don't want it coming out of the ends as it is going the length of the end of my yard, so water would come down, hit the tile and then go out the ends in each of my neighbors yards.

All suggestions are appreciated. I was thinking about building a dry well, but the ground here doesn't seem to soak up the water well. I dug down 2 feet to install my fence posts and ran into ground water just sitting there.
 
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Old 03-03-11, 03:35 PM
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Stay away from the dry well idea for the reasons you already mentioned. The drain tile needs to be sloped. Have it come through the front of the wall. You can do that at each end, or in the middle.
 
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Old 03-03-11, 05:27 PM
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Doing the wall with stackable blocks is fine, but not all of them can be used to achieve the 4' of height you're talking about. Research them carefully!

Drainage -- a perforated pipe on the uphill side of the wall. Slope it either to the ends or to the center. If you slope to the ends, elbow each end and continue a drain line under the wall and downhill from there. If you slope it to the center, use a tee, and continue a drain line under the wall and downhill from there.

Standing water in the fence posts holes doesn't sound good. Your dirt doesn't perk very well. Because of that, continue the drain lines to a storm drain, street gutter, or wherever, or you'll need to build a leach field as well.
 
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Old 03-03-11, 06:04 PM
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I was looking at using paveston brighton series

they are 16" wide, and 6" high, 52lbs each, says in the manual you can go 8 courses high, I should be good right?
http://www.pavestone.com/web-media/c...CM%20156v7.pdf
 
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Old 03-04-11, 03:42 AM
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Those are fine to stack 8 high, which will give you a wall close to 4' tall. All of the work is in the 1st course -- digging the trench, adding the base, getting it even and as level or sloped as needed, etc. After that, you're just stacking blocks.
 
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Old 03-04-11, 06:21 AM
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I haven't read their instructions, but there should be at least one course below grade.
 
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Old 03-04-11, 06:39 AM
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Yes, the wall will actually come in about 3-1/2' tall. The 1st course is below grade, the top 7 are exposed.
 
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Old 03-04-11, 12:39 PM
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cool, I think that would be fine, now the hard part.. doing the work!

Thanks for the replies everyone!
 
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Old 03-04-11, 02:08 PM
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OH yeah!!

Been there, done that, several times, so I can offer a few tips.

Delivery of the blocks. I've got a 2500HD -- I can carry a full pallet of the blocks, and that has allowed me to back in fairly close to their final resting place. Saves a lot of carrying. DON'T try putting a full pallet in anything smaller!! If your pickup isn't that big, have them delivered.

Level front to back on the blocks is important. You don't want the block tops to lean forward or backwards.

Start at the lowest point in your run and work uphill if you are dealing with a slope. Use a string to get the blocks straight side to side, as close to level as possible if you are running up hill. If your bottom course gets buried deeper than the height of a full block, jump up and start a second course as your base. Burying the first course is important. Burying 2 courses is a waste of blocks.

Cutting them to fit -- Either those abrasive masonary blades for a Skil Saw or a diamond blade works. Score the top and bottom and use a chisel to snap them at the score lines. There's usually not a lot of cutting involved -- only at the ends, or at a corner if you are forming one.

Don't be afraid to come back to this thread and ask questions.
 
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Old 03-07-11, 02:20 PM
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awesome reply, this rocks a lot, I was about to ask some questions, now I don't have to Thanks a lot, again, this is very much appreciated
 
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Old 03-07-11, 03:14 PM
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Originally Posted by lefty View Post

Cutting them to fit -- Either those abrasive masonary blades for a Skil Saw or a diamond blade works. Score the top and bottom and use a chisel to snap them at the score lines. There's usually not a lot of cutting involved -- only at the ends, or at a corner if you are forming one.
No need to cut all the way through and this gives a clean enough break? Could this be done for miters?
 
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Old 03-07-11, 04:21 PM
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Deep scores on both the top and bottom, then use a masonary chisel to split the block at the kerfs. Putting it in a bed of sand helps. I've only had a failure rate of one to two percent doing it that way. The deeper the cuts, the better, but the blocks ARE split faced to begin with, so I rarely go more than an inch deep on each side. You can always use the chisel as needed to clean up any wide spots that are keeping the block from fitting.
 
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