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Search results for category "Retaining Walls".
Found 6 question(s). Displayed from 1 to 5 question(s).
Question 1     November 16, 2008

Category:  Retaining Walls

Subject:  Retaining Wall Around A Spa

Can retaining wall blocks be used to build around a spa that is partially in ground? The spa is about 3 feet deep, with about 19" above ground.


I see no reason why you could not use retaining wall blocks around the circumference of the sunken spa…

I would suggest the highland retaining wall blocks, and glue every course with a heavy duty concrete adhesive.

See for details on Highland retaining wall install.

Moderator 9
Replies: NO
Question 2     July 05, 2006

Category:  Retaining Walls

Subject:  Installation of Geogrid

I am having an addition put on to my house, with a below level garage. The excavation has left me with the task of building a retaining wall along side of my new driveway. The wall will be 7ft at the house corner and
2-3 ft at the road, as well as being approx. 30 ft long.

I have been searching the internet and books for installing geogrid, but can not find any good resources.
Would you be able to point me in the right direction?

Hi Mr, Cebollero,

First off you need to know that typically an engineer is the only person who can determine where in a wall to place geo-grid and how far back it needs to go. There are a lot of contributing factors that go into determining this not least of which include, type of soil, slope or angle of repose, height of wall, is wall set back of vertical, type of block and pin system, water issues and so on.

As a result you will not get much information on grid placement for your project as nobody wants to give you misinformation and have something go wrong which may lead to a law suit. I have included some web sites that may help but to be honest I would recommend you get an engineer involved to be on the safe side.

If you contact your local supplier they may have a listing for one in your area.

Johnny O'
Replies: NO
Question 3     June 05, 2006

Category:  Retaining Walls

Subject:  Keystone Vs. Anchor Diamond Pro

I'm currently shopping contractors for building a 90 ft long, 4ft high retaining wall in my backyard (simply for aestetics and to keep the dogs in). I have 2 quotes currently with a huge difference in cost -- one for a Keystone wall system and one using Anchor Diamond Pro. I was wondering what the differences are in these products and which (in the experts opinion) is the better product for this type of project.

It would be hard to answer your question without some more information, but allow me to outline the differences between Anchor Diamond and Keystone Compac.

Keystone relies on a pin connection whereas Anchor has a rear lip that assist with alignment. Being that you are building a 4' wall it would probably be wise to use a product called Geogrid in order to distribute weight of the earthen mass behind the wall to provide structural integrity.

The Keystone pin system ensures at least 2 points of connection with the grid and also prohibits pullout of the grid when pulling the grid taught as it is placed. Anchor products simply rely on the weight of the units above the grid layer to keep it in place.

Some of the differences in cost of an installed retaining wall can also be attributed to the contractor you are using, and the placement of grid behind the wall. Some contractors will simply stack blocks in front of the earth that needs to be retained and you are at the very limit, depending on your job conditions, on whether that wall would fail or function. I would strongly recommend you make sure you are comfortable with the contractor and ask if he will be using Geogrid, if they are unaware of what you are talking about then I would dismiss them as a qualified contractor.

Both walls will give similar looks at the face of the wall after it is being built. The functionality of both are dependent on design integrity and proper installation.

I hope this sheds some light on your question, if you have further questions do not hesitate to call Scott Robinson @ 704-361-0408 or myself.

Billy Patterson
Hardscapes Sales Manager
Goria Enterprises
(336) 375-5656

Replies: NO
Question 4     May 20, 2006

Category:  Retaining Walls

Subject:  Base footing

About to start a retaining wall. Oringinal wall was leaning & then started to fall. When we started project, we began to dig but we hit what appears to be cement base for a foundation of the previous walll. Background first: There is a 3 foot drop to my neighbors property. This foundation is level with my neighbors grass.

My question is:
Should I use this concrete foundation? or will it cause some future problem?
Do I place gravel on this foundation & then begin to build wall?
My concern here is that when the water comes, it will wash away all the gravel & the wall will eventually fall again. I do not want to have redo this project in 10-15 years. Do I jack hammer this foundation & dig the recommended 1inch for every 8inches of the wall? Open for suggestions.

Glad to hear you want the wall to last a long long long time. This being the case, I would start from scratch. First remove the currnent concrete footer. You want to have 10-12% of the total height of your wall buried.

Add the buried amount to 6-inches. 6-inches will be your aggregate base depth. The sum of these two numbers will be how deep your trench needs to be be from the turf line. I would also excavate the trench 24-inches wide. This will allow you to use a plate compactor in the trench.

Best of luck on your project.

Rex Mann

Replies: NO
Question 5     January 11, 2006

Category:  Retaining Walls

Subject:  Inside corner

I'm building a home with a barn for my horses in Cornville ( near Cotton Wood Az.) The 2 1/2 acre site is contoured and elevated. The site for the 48 ft x 68 ft barn had a
7 1/2 ft drop across the diagonal corners. we dropped the high corner down buy 3 1/2 feet and are back filling and tamping the low corner.
However the hill side to the high corner side continues up for another 15 or 20 feet of elevation.
I want to terrace this high corner in about 3 teirs to
re-direct the rain water run off around the barn, on two sides, letting it flow to a natural depression for collection.
The first level would be elevated at about 5 feet up the slope and 12 feet away from the barn footing at the corner slopeing to zero elevation in two direction as the terrain slopes away from the foundation. The highest point of the wall itself might be 4 ft. The legs of this first retainer wall would be about 30 ft ( on the 48 ft side of the barn) and 40 ft ( on the 68 ft side of the barn)
The second wall would elevated about 3 ft over the first and 6 ft behind the first with legs on either side also sloping to zero.
I would guess a 3rd wall would be required.
The question is: This type retainer wall creates inside corners. Almost all of the retainer walls I see are configured to an outside corner and the shape of the retainer blocks I have seen would lend themselves to this outside corner configuration much easier than an inside corner.
Can I build stable walls with inside corners ????


The answer to your question is “Yes”.
The wall would need to be reinforced to support the loads of the upper wall. You will also need good compaction at the corners especially (walls tend to be weaker at the corners).

There is a geogrid procedure I’d like to explain to you. Please call me directly at your earliest convenience. Also visit for more info.

Paul Perez
(602) 818-7761

Replies: NO
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