Retaing wall with concrete interlocking
carver
| Posted in Construction Techniques on
Anyone with experience with the cast concrete units.? I, as H O, would like to build a low (<45″ maximum height) retaining wall along both sides of driveway including around the 24″ culverts. The drive to then be paved with asphalt.
Is mortar recommended? necessary?
How about base? I was thinking a trench ~12″ deep below the bottom of the first course filled with ~ 6″ of crushed stone and dust then ~6″ of sand.
Am I way off base?
Replies
Were having large amounts of retaing walls installed as we speak. Heres how the Pros do it.
Very important to have a firm level base. They compact the area with a large tamper (wacker). Then install about a foot of recycled concrete (3/4"). Then install block. They also use a mat between every 4th course (Geo grid) this keeps the wall from moving at & after backfill. Here is some photos from 2:45 pm today. No need for mortar if you use the right type of block. Let us know if you need more Info, were putting in about 4000 block this week !
iirc most manufacurers have instructions.
there are many styles
bobl Volo, non valeo
Baloney detecter
Here is a few more to get the juices flowing when your Hump-ing the blocks around. I think outside of the digging/backfill, the handling of the block is the big labor factor. The guys we use have all the stuff to move & dig. If I recall right we pay $14 a sq.ft for walls. With the cost of the block @ $5-6 per block which is 16"w by 12"high.
You would think I got a thing for the Wacker,
Puter problems, few more....
Looks like your "Building America" project. Can you get a cost per square foot cost on those walls?
All: I think a rule of thumb is that anything > 48" must be engineered.
To the original poster: At least 1/2 of the first course must be buried.
Matt,
Same project, I would reason when the project is over we will have $250K+ in wall costs. They charge us $14 a sq.ft for the walls. The company we use is not the cheapest in town, more towards the other end of the scale. They do the same here, no walls over 4' tall & bury the 1st block.
Doing a large $50K wall right now that will take the next week to finish, they ran out of block & making more to finish. Will post when the walls are complete.
Recently, I got a price of $30 a sq foot. I was floored! I'm thinking that the block and other materials must be cheaper there, and perhaps the labor too. Here, those walls are not uncommon, but more for commercial projects. I'm guessing that since the topology is somewhat flat here, the walls are much less common than, say in CO where you live, and therefore they are more expensive here in NC.
5 years back I built one in my back yard around our pool that ended up being about $9 a sq ft. That was using those rinky dink 65# (I think) blocks they sell at Blows. It included 2 labors for a day, gravel, and drainage pipe. That did not include my time.
Just for giggles, what is the price for, say 1.5" stone (gravel) there? It's about $12 a ton here (not including delivery).
Matt,
$30 a sq.ft. thats RICH! Here you can find companys that do it for $10-$12 a sq. ft.
Block prices for large block runs $6-$12 per block. The $12 stuff is real nice, looks like stone from 25'. Labor runs anywhere from guys getting $10- $18 per hr. We only use companys that have full Ins.& W.Comp. A large amount of landscapers doing retaining wall. The guys we use only do walls & we have been using them for the past 5 years.
On the price of Rock, we use alot of Recycled Concrete about $10 a ton with $85 extra for trucking. Had a load of 3/4 rock few weeks ago & I think it was $285 for 12 tons, about $17 per ton.
Hummm... material prices sound about the same. I figured stone would be cheap there since the whole place is made out of it... I haven't seen recycled concrete around here. Does it come in "washed"? It was a landscaper I got the high $ price from. There must be cheaper guys around...
On the recycled concrete, will have to check to see if its washed. The stuff we get looks clean. Great product when used in the right places.
Matt,
Where is "here"? I am in Richmond VA
if you click on my name you will see my profile.
Really though, I was just letting you know that this stuff is not cheap...
Here is one of the few walls being installed this week. Weather is getting cold so this 3 tier wall might not get finished this week.
Update on the last photos. Between the weather & the stories of how they ran out of block ( not that were buying that one!)
Crew was back in action this week. They still have a long ways to go, 5pm today!
Do they use some adhesive on those or are they available for late night pick up!
I heard of a wall like that around here(kinda secluded and on a new lot) that sorta disappeared one night, don't know how many trips they would have to have taken but I guess the wall was pretty much gone in one night.
Doug
Doug,
Have had a lot of stuff missing, the Block has been safe so far. 45lbs + each. Have to be careful when you cut the bands on the pallets, the block allways moves around when you cut the bands. Sure would hate to have one drop on a foot during a Mid-night run!
Other job site the company has down in the city, they caught some bums in a 1 ton with 60 sheets of 3/4 ply. Charges will be pressed!
Few more updates from Friday pm,
I did one with the smaller blocks about 8-9 years ago. It was literally right next to the street. Blocks started dissapearing this past summer. The HO called me and just glued the top course down. He hasn't lost a one since then.
Dave
I had thought that while watching someone on the tube(maybe Dean and Jo Jo) they were putting some kind of adhesive on the cap, just as you mentioned.
If you're looking at the modular block items (e.g Keystone) those manufacturers do NOT typically recommend mortared joints. Each course is "pinned" to align with the underlying course. Ensure that you provide for clean stone and an ADS type drain behind the wall to discharge groundwater. Ask the manufacturer for guidance and installation instructions.
Back in the spring Taunton published a magazine of Home Projects that a competent HO could manage. One of the articles dealt with the installation of a retaining wall constructed with pre-cast concrete blocks made for this purpose. Rough front appearance combined with level top and bottom surfaces and standard size.
The article dealt with all aspects of construction from foundation to the installation of the cap blocks. I believe sources were also provided.
Perhaps Taunton still has some of the magazine available. Good luck.