I'm looking to do some landscaping in the yard this season. I'd like to build a small (12"-16" high x 29' long) retaining wall next to the house. I'd like to use cinder blocks to do this. I plan on dry stacking them with maybe some landscape adhesive between them. My dilemma is the footing for the blocks. Most situations seem to call for a concrete footing which I really don't want to deal with. My idea is to dig about 6" down, tamp and then pour in some dry concrete mix up to about 2 inches thick, then set the first row of cinder blocks. Then, I would come back with a garden sprayer and soak down the blocks and cement mix underneath. Also, maybe the next day wet them down again. After that, stack my blocks as normal and potentially come back with some surface bonding cement in a color to match other landscaping. Thoughts??
Anybody ever try this??
- Thread starter vdubee
- Start date
You can do that but don't expect it to last a dozen years. If you are going that route just dump the dry bags and soak the living **** out of it. Then tamp, the excess water won't hurt a thing and it'll bond much better, just takes more time to cure.
Kevin54
MEMBER EMERITUS
I built a large paver patio 13 years ago, 20 x 30 x 16", using split faced block for the walls, backfilled with gravel and capped with flat block. We used construction adhesive on the block and it is still standing today.
bczygan
Well-known member
You don't state your location! If you are in a freeze thaw area, I don't think it will last a winter. If you are not in a cold climate, I would still dig deeper and put a layer of gravel, to provide drainage, then you would need a layer of sand for leveling and also drainage pipes thru the wall every 10ft or so. Personally, I don't think you would need the concrete footer, if you put in good drainage. I built one 8 years ago,70ft. long with just sand and gravel as a base and it is straight and level still today (in WV), although I used the dry stacking landscape blocs with a lip on the back side.
ScottsGT
Well-known member
Don't they call those dikes in your area? LOL!
kwschumm
Well-known member
Those types of walls usually fail because they don't account for hydrostatic pressure build-up behind the wall as water accumulates. Drainage is very important.
It would be far better to lay a compacted gravel base, lay the first course, place a perforated drain behind the first course that drains to daylight somewhere, add more gravel, compact, lay the second course, add more gravel, compact, lay the third course, etc... The top 6-8 inches of backfill can be soil.
For real reliability you'd probably want some of that kevlar mesh between every course or two extending back through the gravel to "hold back" the wall.
It would be far better to lay a compacted gravel base, lay the first course, place a perforated drain behind the first course that drains to daylight somewhere, add more gravel, compact, lay the second course, add more gravel, compact, lay the third course, etc... The top 6-8 inches of backfill can be soil.
For real reliability you'd probably want some of that kevlar mesh between every course or two extending back through the gravel to "hold back" the wall.
joe_padavano
Well-known member
I've got a 300 year old log house with a dry stack foundation and basement. The basement is a walk-out, so the front walls are very much retaining walls. I think that after 300 years, they have been proven not to be "temporary".
Dry stack retaining walls work fine if you build it correctly. Unfortunately, there are lots of incorrectly built examples that fail. The "footing" is simply larger stones. Be sure to angle the wall back into the bank as you built. Turn some long stones into the bank to anchor the wall. And be careful to select stones that fit properly. This is a jigsaw puzzle. I've built a few myself and while time consuming to do it right, the result is more than structurally sound.
four.cycle
Well-known member
joe_padavano said:
^ this.
I've never used cinderblock or cement stones - just quarry rock - mostly black basalt, which is in abundance here.
None of those I've constructed has failed - highest being about 36" at its highest point and longest maybe 50 feet.
Bottom course I always set just a bit below grade, and slope back toward the bank just a bit. Drainage is key - water will push a wall down real fast here.
Never heard of using a concrete "footing" - that's news to me.
theoldwizard1
Well-known member
Is it just a wall or is it a retaining wall (holding back soil) ?
theoldwizard1
Well-known member
WHERE ARE YOU LOCATED ! Put it in you Control Panel !
If you are holding back soil, a dry stack concrete block wall is just not going to cut it. I don't think adhesive is good, long term.
This will cost you more but it wall also last longer. Use SOLID landscape blocks. Dig a trench a couple of inches wider than the block and 4-6" deeper than the block. Fill it with 2-4" of "slag" (crushed stone) and tamp. Lay your first block so that it is 75-100% BELOW GRADE.
If what you are holding back rises above your 14-16" height, you need drainage BEHIND the wall, and gravel back fill. If you are trying to prevent water from getting to your house foundation/basement, then drainage BEHIND the wall is CRITICAL !
redmondjp
Well-known member
Can't say this enough as stated above - drainage is key - I live in a wet area, and it's common here to leave a 6-8" wide channel of well-draining material right behind the retaining wall, using landscaping fabric against the soil, along with a drainpipe buried along the bottom to carry the water away.
Zeke
Well-known member
Carves
Well-known member
Another option that may, or may not be, of use to you.
theoldwizard1
Well-known member
Because they cost more !
Richard Cranium
Well-known member
I have seen people put little pieces of pvc into their walls to let the water pressure drain.