[steddy]

Title pretty much says it all.
I was adamant not to do a retaining wall on our new homestead. I figured we could fill enough to get away from them. Bummer... geometry of the house dictates we need a small one due to how far we built up and how shallow the house is right there. Hill behind garage ended up too steep.

Plan is dig down about 3 feet, and form up about a 5’ tall poured reinforced concrete wall, tapering down to finish grade maybe 8-10’ away. Maybe drill/dowel into the house wall with rebar. Lots of vertical and horizontal rebar.

Hopefully our builder will bail me out if I screw it up to bad.
I have no experience with retaining wall or concrete work experience, so here we go!

 

[poncho62]

When I read the title, I thought this was going to be political.......lol

I don't know anything about retaining walls, but to me, tying it to the house foundation isn't a good idea. Would rather have the wall fall down and not drag the house with it....I may be wrong.....Just sayin'

 

[LLigetfa]

I would tie it back to deadmen but not to the house for the aforementioned reason. I too thought the title to be other than self-deprecating.

 

[Obscured_by_Clouds]

Hey, I resemble that remark!!!

Mine almost fell down go boom.

I don't do mortar joints, so I stacked concrete block with the intent of pouring dry concrete inside the block to let it form into a solid wall. Sections I got farther along with worked OK. But there was that o-n-e section (there's always one, isn't there?) that I didn't get far enough along with before the rains came. And gooolllleeee, did they come, three days worth. Washed enough dirt down from the back side to shift most of the block about 3-4 inches. It stayed standing, but I had loads of fun un-stacking the block and scooping out enough mud to get it back over where I wanted it.

Even now, it's no where as neat as it was and it'll always remind me ......

 

[CCMoe]

steddy,

I would study this for a bit before you continue on.

Retaining walls are a tricky build, IMO.

Conditions vary so much, requiring different types of footings, fill, etc.

One quick thing I noticed was a gravel round rock drainage fill, a PVC weep hole to release water, footings raised on one side to hold wall in place.

Many variables to consider, a bad retaining wall will work for several years but once gives way, it is going to move, tilt, fall, which are none of the things you want to do ten years down the road.

A little study time now would be time well spent IMO.

CCMoe

 

[Kbeitz]

I always step and tilt towards the bank when building one...

 

[Greybeard09]

I always step and tilt towards the bank when building one...

I've never built one but always thought this was necessary...

 

[steddy]

steddy,

I would study this for a bit before you continue on.

Retaining walls are a tricky build, IMO.

Conditions vary so much, requiring different types of footings, fill, etc.

One quick thing I noticed was a gravel round rock drainage fill, a PVC weep hole to release water, footings raised on one side to hold wall in place.

Many variables to consider, a bad retaining wall will work for several years but once gives way, it is going to move, tilt, fall, which are none of the things you want to do ten years down the road.

A little study time now would be time well spent IMO.

CCMoe

Dang... I didn't think my pictures were all that good. You actually picked up on a lot. There might be a couple things else to take in as well. Third picture shows a white string where I was planning to have the top of the wall be. In the foreground is my cordless drill for some scale. Measuring, the visible side of the wall will be about 18-20" above the finished grade at the tall end, and buried about 3' below finished grade. Overall length will be maybe 9'. I also lowered the end of the string a little after I took that third picture, so the wall will be even shorter than what's seen. Also, about half of the wall, which will only be about 10" above grade, will be sitting on hardpan. I was kind of hoping to not need a deadman, since being buried 3' down would pretty much keep it from toppling over (or so I think). And yes... Lots of vertical 5/8 chunks of rebar on the tension side to keep it from snapping like a twig. There will be much horizontal rebar as well, since due to the taper there will be more pressure on the house end than the grade end. It will not block the drain tile that's poking out, as this retaining wall will basically be a continuation of the wall that's there. There will be a rain gutter downspout which could be there, but I'll be putting in a french drain to route the water 30' away, so hopefully that will be a non-issue.

The whole thing stems from that one corner of the back of the house on the short wall. Had I had the foresight, I would have had the concrete taller, so I wouldn't be risking contacting the wood with dirt, thus avoiding the whole need for this retaining wall.

I did consider a deadman as well, but can't quite brain good enough to figure out how to integrate one into this design, which is why I was thinking of burying it down 3'. I'm open to suggestions on that one. The dirt in the background is actually quite a bit of excavation out sideways and down, not what this wall will be holding back. [{<edit here: worded wrong. The dirt in the background is much MORE than what this wall will be holding back. That pile is about 6' tall. This wall only needs to be about knee high. I pushed dirt out about 5' from both sides of the 24" wide trench I dug>}].

I also considered pouring a wider footing (maybe 20" wide for this 6" thick wall) in the bottom of the trench where it's dug down below the hardpan, with rebar sticking up, to try and aid with the vertical stabilization. Haven't ruled either of those possibilities out.

I'll definitely have the builder look at it before going any farther. He does reinforced poured concrete pretty well. We've done some pretty cool things with it on this build already - porch and deck pillars/beam. I'd like this wall to match that. I want this house to be incredibly robust, without too many superficial architectural details. Most of that is going where it will never be noticed - inside the walls, under floors, and underground. Lots of concrete - simple; strong. I think this wall kind of fits in with that utilitarian looks plan.

 

[CCMoe]

steddy,

It's hard to make any recommendations not seeing it in person and then I would consult a professional in the field.

This is not a suggestion but I've always thought the screw in rods that utilities use for guy wires on telephone poles would make great dead man anchors.

One reference that I have is "Complete Construction / Masonry and Concrete" there are lots of books on eBay that would meet your needs.

Good Luck,
CCMoe

 

[NicoR]

Retaining walls are easy when you use block. I've built many of them. Most of what I've used are the big 75# concrete blocks that are 8"Hx18"Wx12"D. Just need to make sure you have a good base and get your bottom row right. Having a front end loader full of block at the right level helps as well.

I've built ones about six block high that are still up and not sagging. The key to your base is either a poured concrete footer or a good layer of hard packed 1" dirty base about 4-6" thick depending on your wall height. Then add about 1-2" of loose dirty base to settle the block into to get it level and even with the ones around it. After you get your bottom layer done, it's all stacking.

When you're holding back a hill like that, you'll want about three foot open behind it so when you hit three block high you can lay a reinforcment layer in. One brand is Geomat. Rubber coated polyester netting you use over the layer of brick, over your packed in backfill. Then you add another three or four layers of block and back fill again. On your bottom three layers of block in a six block high wall you'll want to fill the blocks themselves with dirty base so they for a more solid wall. Wet it down some once filled so it flows down and fills the gaps. The ones above that you can use clean gravel to promote drainage.

Speaking of drainage, you'll want to drop some clean 1" limestone gravel, 2-4 inches will do, run some 4" prefferiated pipe along the bottom of your wall and out to the surface of the dirt at the far downhill side for drainage. Cover the pipe with more gravel. You'll only need enough for an area of gravel about 6" wide for the pipe. Then you can add what ever you have available for back fill behind the wall to fill it in.

There are many types of block available. The blocks I talked about above have a small tit on the back to keep them from scooting over the top of the one under it. Each higher tier sits a little further back and gives the wall a leaned appearance. You can make curved walls or straight with them. As with your wall I'd curve the wall around twoards the front of it so you can make it shorter and just play with the grade around the end of it.

 

[NicoR]

steddy,


This is not a suggestion but I've always thought the screw in rods that utilities use for guy wires on telephone poles would make great dead man anchors.


CCMoe

Those things are about six foot long and they use the same hydro motor that they use to bore the pole hole to install those.

 

[Ariens93GT20]

Footing minimum 3 foot wide and 1 foot deep. Place the wall 6 inches from the top side of fill. I would suggest an 8 inch wall. Two layers of #4 bar at 12" each way in the footings with L shaped #5 vertical bar at 6" spacing. #4 bar at 12 inches horizontal should be fine. I would also key the wall into the footing. Or just find a structural engineer and let them design it. Better to do this once and over build as to have to do it again later.

 

[Country1966?]

I would spend the money on an actual retaining wall block.

I built one using that and it isn't difficult at all and held for 10 years and still there. It also looks nice.

I did put in drainage and gravel behind the block.

 

[TUDOR]

Climate change, otherwise known as global warming in many parts of the world, is not a concern in the spring, summer, or fall, but I haven't really noticed any warming trend in the winter in these parts. Frost is still a concern if the soil holds water, and frost hasn't been mentioned.

 

[DoItMyself]

I've done a number of retaining walls in the past couple of decades. Every one of them is still standing in the same position that it was built in.
On every retaining wall I've done (concrete block, poured concrete, retaining wall block and wood) I've used deadmen and drainage behind it, weep holes, and solid footings. And I would never, ever tie one into the foundation of a house. Ever.

There has to be a lot of planning and grading to get the drainage right. Get it right and you'll have a solid wall that will last just about forever. Get it wrong and you'll have a mess that will keep reminding you that you screwed up.

Personally, I don't like the look of poured concrete walls in a residential setting.

I don't do mortar joints, so I stacked concrete block with the intent of pouring dry concrete inside the block to let it form into a solid wall. Sections I got farther along with worked OK. But there was that o-n-e section (there's always one, isn't there?) that I didn't get far enough along with before the rains came. And gooolllleeee, did they come, three days worth. Washed enough dirt down from the back side to shift most of the block about 3-4 inches. It stayed standing, but I had loads of fun un-stacking the block and scooping out enough mud to get it back over where I wanted it.

There's nothing difficult about mortar joints, and it's the right way to do a concrete block wall. Just shoving a bunch of concrete in the holes and hoping it works...isn't.

 

[Cat385B]

If the concrete left of the window in the first pic gets buried, I vote for a block retaining wall. Install geogrid mat 3 or 4 courses up in the first 5’ out from the house and again near the top, and run drain tile level from the wall termination point back to the house. Daylight the tile end, but have a pea rock sump 2’ deep at that location. With all the import sand there, you won’t have any water issues.

 

[SteelPE2]

A retaining wall with sloping backfill is very tricky to design due to the increased soil pressures from the sloping backfill. I have designed hundreds of concrete retaining walls. I typically don’t get into modular block walls though.

This is a fun little quick video you can watch on how engineers can get high walls to work.

 

[Trying2mow]

Title pretty much says it all.
I was adamant not to do a retaining wall on our new homestead. I figured we could fill enough to get away from them. Bummer... geometry of the house dictates we need a small one due to how far we built up and how shallow the house is right there. Hill behind garage ended up too steep.

Plan is dig down about 3 feet, and form up about a 5’ tall poured reinforced concrete wall, tapering down to finish grade maybe 8-10’ away. Maybe drill/dowel into the house wall with rebar. Lots of vertical and horizontal rebar.

Hopefully our builder will bail me out if I screw it up to bad.
I have no experience with retaining wall or concrete work experience, so here we go!

You will need several deadman anchors and double your rods inside of the concrete blocks. You are STILL going to have lattice cracks but it should hold about 20-30 yrs if you lattice with 4" of asbestos reinforced concrete out 8" and take it down with 4" pipe about 10 ft deep and 10 ft apart.:tango_face_wink:

 

[steddy]

Builder took over project. He framed in the footings Monday about 2’ deep. It will be doweled into reinforced basement wall in 3 places.
All told, it will be holding back maybe 8-10 yards that would eventually flatten out if not retained. Too small to be concerned with drainage. The drain sock shown in the picture will probably never encounter water, as it’s actually above grade.

He knows his stuff and he’s seen the circumstance. My pictures really do make the circumstances look much worse with that big pile in the background... that pile includes backfill from BOTH sides of the wall, peeled back about 6 feet on each side. Finished Wall will protrude above by about 16”, and much less as it gets farther from the house. In comparison, the basement wall about 7 feet farther uphill is holding back 5 vertical feet of fill, with similar construction method as the retaining wall.

If he isn’t concerned, neither am I.

 

[Trying2mow]

Bravo..it seems that you have it under control...the pics had me believing that you were anticipating a far more ardous task.[ B ]