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Discussion Starter · #1 ·
Hello,

I'm building a 3' tall wall around my a/c compressor (Yes, I have allowed sufficient clearance for air circulation.).

I'm building the wall with retaining wall blocks, but I'm knocking off the lip so that I can build the wall plumb (not canted backward) and it will not be used to retain soil.

The wall is 13' long x 3' tall with one 90-degree outisde curve to the left followed five-feet later by a 90-degree square corner to the right.

My main question: Is it okay to secure the blocks with PL Landscaping Block Adhesive instead of mortar?

Also, I dug the trench 10" deep and have filled it with 4" of hand tamped paver base (didn't use a vibroplate, just my arms, back and a 8" hand tamper). Is that sufficient?

Lastly, just how level does the paver base need to be?

Thanks in advance for your help!
 

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Tileguy
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The base (footing) should be below the frost-line, should it not. That's going to be more than 10" more than likely. It should be level.:)

If the PL product is made for the retaining wall blocks then why wouldn't you be able to use it?:)
 

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Discussion Starter · #3 ·
Hi Bud,

I'm in California where there is no frost line but thanks for the suggestion.

As to PL adhesive claiming to be good for this applicaton, they don't list any parameters like "for walls up to x height".

I'm hoping that people who have experience with the product will be able to give an opinion based on their real-world practical experience.

Chuck

Bud Cline said:
The base (footing) should be below the frost-line, should it not. That's going to be more than 10" more than likely. It should be level.:)

If the PL product is made for the retaining wall blocks then why wouldn't you be able to use it?:)
 

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Tileguy
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I'm hoping that people who have experience with the product will be able to give an opinion based on their real-world practical experience.
Well alrightee then Chuck Chuck Bo Buck:laughing:
I'll shut the hell up and let you deal with another Do-It-Yourselfer rather than someone like me with only thirty-five years experience in this type of thing. You're only going three feet high for Gods sake, it isn't like you were building the Washington Monument.:thumbup:
 

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Discussion Starter · #5 ·
Wow, you're just a little sensitive there Buddy Boy. I said nothing derogatory about you, I didn't say or even suggest anything you said was wrong.

Had you said something in your reply that indicated you have *any* experience with the product rather than just suggesting I should believe what the manufacturer tells me, then I might not have said I'm hoping to get input from people who have actually used the product.

Thanks, Bud, for your invaluable insight.

Bud Cline said:
Well alrightee then Chuck Chuck Bo Buck:laughing:
I'll shut the hell up and let you deal with another Do-It-Yourselfer rather than someone like me with only thirty-five years experience in this type of thing. You're only going three feet high for Gods sake, it isn't like you were building the Washington Monument.:thumbup:
 

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Concrete & Masonry
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Hello,

I'm building a 3' tall wall around my a/c compressor (Yes, I have allowed sufficient clearance for air circulation.).

I'm building the wall with retaining wall blocks, but I'm knocking off the lip so that I can build the wall plumb (not canted backward) and it will not be used to retain soil.

The wall is 13' long x 3' tall with one 90-degree outisde curve to the left followed five-feet later by a 90-degree square corner to the right.

My main question: Is it okay to secure the blocks with PL Landscaping Block Adhesive instead of mortar?

Yes, The PL is a better option in this scenario as it allows more flex & has better adhesion properties than mortar.

Also, I dug the trench 10" deep and have filled it with 4" of hand tamped paver base (didn't use a vibroplate, just my arms, back and a 8" hand tamper). Is that sufficient?

If the gravel is a consistent depth it should be fine. If in doubt, run a fair amount of water over it the day before to let it settle a little more, if it's going to.

Lastly, just how level does the paver base need to be?

Thanks in advance for your help!
It needs to be extremely level. I would suggest using very fine sand or mixed sand directly under the wall to get it as near perfect as possible. It's far easier to get the base right rather than continually pick-up the heavy block to alter each one a tad. The worst case is that you get a few course up & realize the wall is rocking & out of level, as every additional course only amplifies the mistake. Get a long 2x4, temporarily attach a level to it, and screed the sand nice & level right away.

The other thing I would suggest looking into is the max. free-standing height suggested for the block. For some reason, I don't recall any of them recommending that high of a wall,, even on the largest units. If you're not sure, at least give the block dimensions here for some guidance.

And BTW, Bud's mistaken, these walls never need to go below the frost line.
 

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Discussion Starter · #7 ·
jomama45 said:
It needs to be extremely level. I would suggest using very fine sand or mixed sand directly under the wall to get it as near perfect as possible. It's far easier to get the base right rather than continually pick-up the heavy block to alter each one a tad. The worst case is that you get a few course up & realize the wall is rocking & out of level, as every additional course only amplifies the mistake. Get a long 2x4, temporarily attach a level to it, and screed the sand nice & level right away.

The other thing I would suggest looking into is the max. free-standing height suggested for the block. For some reason, I don't recall any of them recommending that high of a wall,, even on the largest units. If you're not sure, at least give the block dimensions here for some guidance.

And BTW, Bud's mistaken, these walls never need to go below the frost line.
JOMAMA45: Thanks for your input regarding leveling. I had thought about sand but concluded it is overkill for this type of wall, but you've made me rethink that: I'll go with the sand. How thick should a layer should the sand be?

The blocks are Anchor (Windor series, I think) retaining wall blocks with the bottom lip hammered off. They're 12" x 8" and are 4" thick. The manufacturer said I'd be okay at 3' height, but I prefer the opinion of people in the trenches (including you Bud) over that of a manufacturer.

SO...
... is 3' is okay?
... how much sand and compacted or loose?
... PL adhesive or mortar?

Thanks all! Your opinions are greatly appreciated.
 

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Discussion Starter · #8 · (Edited)
JOMAMA45: Apologies for asking the same questions that you already answered in red: I was replying from my mobile phone and didn't see them.

Here's a link to an small album of pics that shows the initial phases of construction and layout.

http://goo.gl/CdPVs

Thanks,

Chuck
 

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czissman -

You are using retaining wall block installation methods for the bottom of the wall for a purpose they are not made for. You also went trough the trouble of knocking off the lips, which makes vertical stacking and leveling very, very difficult.

Since you are using Anchor units, the block must have come from a major block producer that make many more regular colored block (cheaper) that could be laid with mortar easier on a minimal concrete footing that just provides a level starting point, just as a compacted soil base does. There are many producers that make block for the typical privacy walls.

In exterior, most adhesives dry out, get brittle and deteriorate with time. One exception is the use of clear silcone that is applied in 4 dabs per block to hold the solid cap block in place on the top of a segmental retaining wall that is never, ever mortared because it is intended to be a wall that cam move and flex.

Is there any way you can change now?

Dick
 

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Discussion Starter · #10 ·
czissman -

Dick, thanks for your comments.

Price is a big factor on this wall, and after having done a fair amount of research these retaining wall blocks from HD were the lowest cost solution (though I certainly may have missed something more economical) and the blocks have already been delivered so I'm pretty well locked into that solution.

The idea of knocking the lip off the blocks to stack them vertically came from the manufacturer. The blocks are 8" deep and knocking off the lip (which takes about 30 seconds per block) removes about 1" of that depth, leaving a 7' contact surface for leveling and bonding. Do you feel that's not enough?

Assuming I have to proceed with these blocks, are you suggesting silicone adhesive for use on all courses? There will be no cap on the wall.

Thanks,

Chuck
 

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Concrete & Masonry
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Looking at their website & instructions, it appears these block are only good up to 2' high, but that is in a situation where they retain soil & actually retain the back lip. I'd personally be aprehensive to use these to go 3' high with only glue on a 7" max. width. They may work fine, but it's a lot of work & cash outlay if it fails in a short time. If you are able to curve the wall rather than construct it straight, I think it would stand up better.

To give you an idea, for privacy walls, we use Versa-Lok double sides block that are 10" wide and receive 2 pins per block to hold them together. I'd still be aprehensive to build them 3' high on a straight wall.
 

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Discussion Starter · #12 ·
The wall actually has a 90-degree curve and a 90-degree corner. Here's a pic of the first course which I placed just to confirm that the trench I dug was shaped right.

The semi-circle in the foreground will be 2' tall, and will surround a fountain.



 

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The silicone is not meant to hold an entire wall together. It is just a standard method used around the world to hold the caps down on high segmental retaining walls that do retain soil.

I think you were mis-led by a guy at an apron store.

When you start in the wrong direction on a small job it become difficult to change directions since the cost of picking up and redelivering a replacement product is too prohibitive to eat.

Anchor and the other 3 major systems all provide vertically stacking interlocking units, but they are intended for larger applications and not for incidental walls, plus, they are more costly, except in large amounts because of the mold cost and inventory costs. The units you bought were landscaping units meant to be installed according to the common methods and they have performed well for many years around the world.

Dick
 

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These are versa lok. They pin and glue together. Glue is good and will hold. The weight of the blocks and the glue will keep it stable as long as it's built within the manufactures specs for max height. Part of the wall should be below grade. Laying sand on top of the stone is for ease of leveling. The first course of blocks must be level or the wall will get worse as you lay additional courses. Also when gluing the blocks tend to shift before the glue sets. So be careful when laying the next course not to knock the wall out of whack.
 

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