DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (
-   Landscaping & Lawn Care (
-   -   Interlocking Block Garden Wall (

joetab24 04-10-2009 08:04 AM

Interlocking Block Garden Wall
I'll let you know up front I've never done this before, but I am a firm believer in learning as much as I can and being patient, so that the end result is a project well done.

So far I've dug a trench. Yesterday, I had some help. I was pressured a bit by my well meaning but pain in the butt! dad to move a little quicker than I have been.

We put a layer of stone down and some paver base. The problem is there is still a decent slope in the trench. (in the photo below the ground slopes from bottom of the screen to the top).

Somebody who has done this before said I should probably build up to the higher end by digging deeper on the low end and adding an extra row of rocks.

You may be able to detect the slope of the trench in this picture.

I know I should have done this better before adding the stone, but I set the stones to the desired height, 3 rows up. I then pulled a string so that it was at the same height and then I used a line level to make sure the string was level. This morning I made a water level and I think I am going to use that to get a level line.

I am now going to have to work on digging the low end deeper. So I will remove the stone we put down and dig deeper to add an additional row of stone, otherwise if I try to level the low end with the high end, some of the first row will not be below grade. Rookie mistake, but I will fix it.

Some earlier pics

Thanks for taking a look.

47_47 04-10-2009 10:15 AM

2 Attachment(s)
The hardest part is getting the base right. After that the wall will fly up. Yes you'll have to level the base course first. I'd carefully remove the base material to either a tarp or wheelbarrow and level the grade. 1/2-3/4 of a block is enough below grade.

As a side note, where are you planning to do with the downspout in pic 3? I wouldn't have it exit behind your wall.

Here's my wall from last summer. Take your time it is not a race and it will be fine.

joetab24 04-10-2009 10:46 AM

Thanks for the reply. I am definitely going to move the downspout extentsion. A few people have given me ideas about how to deal with it.

Should I end the wall against the right patio pillar?

On the left side, I start against the pillar. This is where my property begins.

Here is a wider view

47_47 04-10-2009 11:10 AM

You could turn it back to the right pillar for symmetry or extend it out to the driveway and make two turns back to the pillar. It looks like you have less than 2', I'd lean that way. Do a dry run and decide.

Either way do not butt your wall to the house/porch. Leave a gap (1/2" or so) to allow for movement of the wall.

joetab24 04-10-2009 11:31 AM

interlocking blovk garden wall
I've been watching this video a few times to get some visuals.,00.html

At about 2.15 he checks for plumb against the mason's line. Do you put the level anywhere on the block to do this? I think he says something about the front of the block. I probably should know this, but I don't.

Additionally, how do you make sure you are laying the blocks in a straight line? Did you use a mason's line? If so, should the line touch the front of the block?

Also, some people have suggested knocking off the lip of the block for the first course.

And finally, did you use adhesive for each row. I was under the impression this should only be used for the top stone (capping?) if you are using interlocking blocks.

joetab24 04-10-2009 12:38 PM

interlocking block garden wall
I also haven't squared the corners of the wall using the 3, 4, 5 method. I really hadn't considered this until I was looking through a DIY book from the library. The example in the book was on flat ground. I already have a flower bed so the surfaces are not even. I guess this can be solved with stakes and a plumb bob. Any tips here are appreciated greatly.

concretemasonry 04-10-2009 05:34 PM

Just look at the installation instructions on one of the internet sites by the international segmental retaining wall licensing companies (Allan block, Anchor, Keystone or Versalok). They all have great information that you do not get from the "knock-off" versions.

The first or bottom course should be level or you always fighting through the installation.

joetab24 04-11-2009 02:55 PM

interlocking concrete blocks

Thanks for the reply. I was able to find that Home Depot's Windsor blocks are made by Anchor. There is another company called Pavestone who seems to have info about the Windsor blocks.

kimberland30 04-11-2009 06:38 PM

I just finished a low retaining wall around our tree, and it definately helped to knock the lip off of the first course. We compacted the soil and added paver sand, and without the lip of the stone it was easier to get level.

When placing our block, we leveled each one by taking a small level and placing it across the stone and from front to back. We also made sure the placed stone was level with the one next to it. Every few blocks I'd put the 6' level on it to make sure it was still straight. I purchased a line level but never used it, the regular levels worked just fine.

It's a PITA to get the first course level, but so worth it. Like another person said, once that first course is down the rest will go very quickly.

joetab24 04-21-2009 09:46 PM

i haven't done much since this post because i'm waiting for my new patio to be installed.

i did, however, work on a small section to practice setting the blocks level. i set 3 blocks in 2" of paver base and used leveling sand to level them. i did not fill the whole trench with paver base because i found it easier to add the base, tamp, and level as i moved. it then rained for a few days and the blocks shifted slightly. i don't see myself being able to get the whole first row done in one day. besides praying for a dry spell, would it make sense to add dirt to the front of the block and backfill stone as i move from block to block to keep them in place?

47_47 04-22-2009 07:05 AM


The one course of block will move. The lock together as you add more.

Dry lay the number of course of blocks you plan to use and measure the height of the wall, add for your compacted base material and sand thickness. Set your level string line at the top of your proposed wall and measure down this distance. Take your time and do not disturb any more soil than necessary.

Once done, add and compact your base material. Use the level line and spirit level to get as close as you can to the finished grade height of your compacted base. Now start laying your first course. Use a hand held level and your string to double check as you go.

Added: Estimate your time. Plan on 65% of the time digging your soil and leveling your compacted base, 25% setting the first course and only 10% to finish.

Good luck.

jomama45 04-22-2009 09:02 AM

Joetab, to save a little time on the first course, here's a few things I would do.

- Chisel the majority of the lip off the bottom of the block for the first course.
- Set your string out a few feet in front of the wall, use a tape measure to reference if occasionally.
- Use a four foot level for the tops & to range the back for the first course.
- Use a four foot level to screed your sand PERFECT before you set block.

If you do these things, you should be able to merely tap the block around to level. And if the block aren't perfectly straight on the back (try to keep within 1/4"), the rockface does a good job of hiding it. Have fun!

Tscarborough 04-22-2009 03:39 PM

A couple of things. First, place the string at the rear of the block. The front is split faced and can vary as much as 1-1/2". Second, to get the base course right, you will need a small level and a big level. I use an 18" to level front to back and a 4' to measure down the wall line. This allows you to find small irregularities and the longer the level the more accurate the reading will be.

Knock the lips off, I just beat them with a brick hammer, since it doesn't have to look pretty. Keep a bucket of fines (bigger than concrete sand) with you as you work each block for leveling, and spend the time to get them right. For big walls, I allow 15 minutes per unit when estimating my time.

To make curves, be sure that the gap between each block (at the rear) is the same, and the curve will be perfect.

If the ends are constrained, work from the ends to the middle, so that your cut closer will be lost in the over all wall, and will not compromise wall integrity. If the closer is less than half the width of a block, cut a little off of 2 rather than using a small piece.

If the base of the wall steps down, make the step down at least 2 block into the hill. Step downs are the most common point of failure because people are too lazy to dig that extra little bit.

Good luck and drink lots of beer!

Tscarborough 04-22-2009 03:50 PM

I just looked at your pics. You should probably curve that corner by the downspout. That is an easy mornings work. You may be over thinking it.

joetab24 04-22-2009 04:23 PM


thanks so much for the feedback.

I am finding that I am having a difficult time tamping the soil level. It's close, but I keep finding irregularities. The soil is moist and fairly pliable, since it has been raining so much here in PA. Is it ok to add the paver base and level that or do I have to get the dirt perfectly level? Also, am I supposed to add an inch of sand to the whole trench, or just use the sand to level?

All times are GMT -5. The time now is 01:53 AM.

vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

Search Engine Friendly URLs by vBSEO 3.6.1