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View Full Version : Several Basic Retaining Wall Question's


4 seasons lawn&land
08-06-2009, 11:16 PM
Im looking for some basic construction info on retaining wall's.

First. None of the info I find on line show's any use of seperation fabric, including the versa-lok site. I dont understand how this is considered common practice with walkways/patios and not mentioned anywhere with wall construction. Do you use fabric for walls?

2nd, would doing a retaining wall "the old fashioned way" with simpler construction techniques today be considered "hacking"? There are 100 year old walls around that are backfilled with dirt, faces built a 10 degree slant's, etc. This seem's like it could be a good way to offer a cost effective method to shorter retaining walls as long a you dont try to sell it as "proper". Does anyone offer this?

I found one rule stating, "base for stone walls should be half as wide as the height" 6 ft wall = 3 foot width base. with a min of 2 ft width for all short walls.

Why does versa lok have dirt backfilling the first base layer instead of aggregate?

do you specifically put drainage pipe in with stone walls?

What is the standard for inward slope for a proper stone wall per ft of height?

Too much all at once?

sven1277
08-07-2009, 02:57 PM
The specs for building it the "proper way" are to remove the variables. I just looked at a property where the homeowner built a wall and backfilled only with dirt. No drainage, and he didn't fill the hollow cores with stone. It is still standing a few years later. So far, he's been lucky. Hydraulic pressure and load surcharges behind the wall can affect it. Freeze/thaw cycles and soil conditions are just the basic potential problems that are dealt with when building a wall correctly. I sometimes wonder how those 100 year old walls are still standing. I think they were just lucky with the building conditions. I have seen plenty of walls in dire straits, too.
Generally, the base is twice the width of the block. Most common blocks are 12" deep, so 24" wide base is recommended. You always want to put properly pitched perf pipe behind the wall and daylight it in front of the wall. The wall has process gravel behind the first layer instead of open graded stone so any water behind the wall will flow directly into the pipe, instead of filling the space in the crushed stone.
Do some research, talk to your supplier, take a course, make sure the base is properly compacted, or don't bother trying. You wouldn't hire just anyone to plumb or wire your new house, so don't be that just anyone who builds retaining walls.

4 seasons lawn&land
08-07-2009, 10:07 PM
thanks. what about the seperation fabric? not used? Ive signed up for a class next month but its regular wall. I need to find a retaining wall class too.

DVS Hardscaper
08-07-2009, 11:08 PM
I'm not much of a Versa Lok fan.


Yes, we use filter fabric.

Yes, we use aggregate.

We have a monster wall currently under design and pricing. Really, the wall isn't a whole lot of square footage, but it's a "monster" because the 100(+) year old wall is holding up a very old, big home. The old wall is 11' high. New wall will be 8' high. How we're doing this is we're using a 1,400 pound block, not a 76 pound block. It's going to be quite a project.

stuvecorp
08-07-2009, 11:12 PM
Why does versa lok have dirt backfilling the first base layer instead of aggregate?



Do you mean the first course or the block that is underground? My understanding is you don't want the water going down to the base block but weeping/draining out above ground. I use fabric usually to separate the drain rock from the backfill/native soil. We are mostly sand soil here so it's to keep sand from wicking in to the drain rock.

stuvecorp
08-07-2009, 11:14 PM
I'm not much of a Versa Lok fan.


Yes, we use filter fabric.

Yes, we use aggregate.

We have a monster wall currently under design and pricing. Really, the wall isn't a whole lot of square footage, but it's a "monster" because the 100(+) year old wall is holding up a very old, big home. The old wall is 11' high. New wall will be 8' high. How we're doing this is we're using a 1,400 pound block, not a 76 pound block. It's going to be quite a project.

DVS, what's your experience with Versa Lok?

DVS Hardscaper
08-07-2009, 11:26 PM
DVS, what's your experience with Versa Lok?

VERY little. And yes, we have used it a handfull of times.

The reason we stay away from it is because we have a VERY tight relationship with a company that manufactures Cornerstone, Mesa, and Stong Wall.

Once you use Cornerstone, you won't want to use anythng else.

Cornerstone is the easiest SRW block on the market, in my opinion. It was created not by some nerdy engineer, but by a contractor (by the name of Vern) that has built mega walls all over the United States and Canada. So he took his field experiences and created his own block. Our supplier literally has a block for every scenerio imagionable, which not other suppliers do.

stuvecorp
08-07-2009, 11:39 PM
Interesting, never heard of it but I'll look it up. Versa-lok takes care of me very well. It was the first block I built with when I was at another landscapers and have just stuck with them.

4 seasons lawn&land
08-08-2009, 01:54 PM
Do you mean the first course or the block that is underground? My understanding is you don't want the water going down to the base block but weeping/draining out above ground. I use fabric usually to separate the drain rock from the backfill/native soil. We are mostly sand soil here so it's to keep sand from wicking in to the drain rock.



The underground block, and that makes sence too. Does that apply to just engineered block or does that go for stone also? Most rock walls I see dont have drain pipe coming out the face, just the huge ones.

4 seasons lawn&land
08-08-2009, 02:53 PM
dont let this guy anywhere near a rock wall.

http://www.krukowskistone.com/T_Instr_LRetainWall6.html

Bru75
08-08-2009, 05:18 PM
dont let this guy anywhere near a rock wall.

http://www.krukowskistone.com/T_Instr_LRetainWall6.html

Why not???

4 seasons lawn&land
08-08-2009, 07:19 PM
this part


f. Backfill and compact with native soil.

Bru75
08-08-2009, 11:48 PM
this part


f. Backfill and compact with native soil.


He also said this:
"c. Drain tiles should be placed in coarse gravel at the back of the wall."

Just wondered, cause I didn't see that much wrong with his site.

P.Services
08-09-2009, 12:14 AM
dont let this guy anywhere near a rock wall.

http://www.krukowskistone.com/T_Instr_LRetainWall6.html

why do you say that?

DVS Hardscaper
08-09-2009, 11:56 AM
the base course is buried to keep the wall from moving forward.

1" of block is buried for every 12" of wall height.

sven1277
08-10-2009, 06:31 PM
If you're looking for a retaining wall course, look up NCMA (National Concrete Masonry Association). My instructor was the man who created the Cornerstone brand. Very knowledgeable. Great method for screeding the base.