Retaining wall footing depth

[oosik]

I have one short - 50' long - retaining wall. I dug down about 2 1/2 feet - put down a half foot of gravel - came up with loose cement blocks. No mortar. I'm sure the wall moves with the season but it's still where I installed it 30 years ago. Local codes call for four foot burial for footers.

 

[Diggin It]

Use of the lower side matters too. If it's a patio/seating/play area where people could get hurt, construction needs to be more substantial that if it's for landscaping/flower bed/garden/lawn.

 

[KennyG]

As noted above, it all depends on the soil composition and drainage. If you dig a trench a few feet deep and backfill with gravel, it will probably be stable. I lived in a house with a foundation that was brick laid in a shallow trench in the sand. It was in fine shape after 50 years. However, if you area in heavy clay, it's more of a concern. You could do a ground beam. This would be a poured reinforced concrete foundation (perhaps 8 to 12 inches square) with some deep holes to get down near the frost line. This is how we used to pour foundations for outdoor equipment like large A/C units. We would pour a 4 inch thick pad with a few "postholes" deep below it.

 

[PA hayseed]

Just to add to the myriad of advice offered here, I would suggest you go with a dry stone wall. They have been used for hundreds of years and don't require a footer. Some are rebuilt every 50-75 years or so. If you do dry stone, just remember the length of the stone sits into the wall, not along the wall. People do this wrong all the time, because it uses less material to build and it is quicker.

Here is a link to a place that knows a little something about dry stone Dry Stone Conservancy

The only problem with the dry stone people is that they are located in Kentucky

 

[PILOON]

30 years ago I built a dry stone wall about waist high and it still has not moved.
We are in a 4 foot deep frost zone.
Largest ones are at the base getting smaller as they near the top.
One trick is to make sure the surfaces mate as well as possible and if not seat them in a clay like soil.
Stuffing moss between the spaces also helps.
Don't lay perfectly vertical but tilt the wall back slightly as you build it, like perhaps 5 degrees or so, that way if frost does heave the stones can flop back come spring thaw.

In fact as I think it over all three of my properties have their fair share of stone walls and that in varied soils.
Being lakeside we wanted flattish areas rather than hills hence retaining walls to create terraces.
LOL, they have been there so long that I have actually forgotten about them.
I'll add that I have never needed to do any repairs.

Another trick is (if so equipped) is to pressure wash the faces once the wall is completed for that look of perfection.
Milk or cream will help propagate that mossy aged look.

 

[LouNY]

I don't care for the old style dry stacked stone walls, after a great many years they do shift about and need rebuilding to look good.
I would not consider a loose stacked stone wall for a retaining wall at all.
I have been involved in burying many miles of stone walls to enlarge fields and merge some fields into one to make them easier to work.
I don't like stones doesn't matter if they are stacked in a wall, loose in a field or piles in the corner of a field.

 

[MikeInEburg]

Another very forgiving wall medium are gabion baskets. You can generally just put them on the ground surface. With clay soil, I'd probably still add drainage stone behind.

 

[PA hayseed]

I don't care for the old style dry stacked stone walls, after a great many years they do shift about and need rebuilding to look good.
I would not consider a loose stacked stone wall for a retaining wall at all.
I have been involved in burying many miles of stone walls to enlarge fields and merge some fields into one to make them easier to work.
I don't like stones doesn't matter if they are stacked in a wall, loose in a field or piles in the corner of a field.

You may like them you will see
You may like them in a tree
Sorry, your response had me thinking green eggs and ham. I wish I could have taken some pictures of those stone walls you took down. There are a lot of varieties of stone walls.

For the OP, I have 4 retaining walls made of dry stack stone around my house (big stones). The one set of walls are used to retain about 4' of ground (tapering out) around my basement door so I can walk out. 10 years so far with no issues. The other two are around my driveway.

 

[lennyzx11]

I actually have did dry stack and mortar field stones. Used to be a hobby. I haven’t did any since moving from Oklahoma to Vermont last year. I may do that but thinking that blocks would go quicker. Especially at the pace I work!

 

[AllByteNoBark]

I would use the large retaining stone blocks. Bury the first one and make sure it is level and build up from there. Make sure and put the fabric behind them as AllDodge mentioned so they can drain but dirt will not wash out. They work really well and hold well. I have used them for some pretty substantial walls and never had an issue. The key is to get the first row that is buried on good solid ground and make sure it is level both direction, front to back, and side to side.