Flagstone dry stone retaining wall

Newbie posting here... I hope the photos come through...

In the beginning, around 1960, there was a wall; a dry stone flagstone breast wall, extending approximately 15 yards, sloping from 7’ to 2’ as it goes. The owners decided to plant vines along this wall, evergreen vines to look nice and act as groundcover for the slope behind it. The  owners looked at this and said it was good. But alas, it wasn’t. Those were Euonymus fortune (wintercreeper) vines. Over time, (decades, apparently) the wintercreeper was no longer a ground cover – it totally concealed the wall and became a hedge at the top of the wall. Then the bank foreclosed on the house. It sat empty for 4 years, during which time, a family of groundhogs (woodchucks) decided the hedge and the nice well drained slope would make an excellent home.

This is when we purchased the home.
https://imgur.com/TxeoS3U
There was a burrow entrance at the base of the wall, another near the top of the slope and a third about halfway down. After trapping 4 groundhogs (nasty critters!) and still sighting more, we decided the only way to remove the ground hogs is to remove their habitat. So we removed nearly all of the wintercreeper that we could. (For those familiar with this horticultural plague, you know it will be a recurring battle to keep it away.)

With the wall covering and hedge removed, we could see the extent of the damage those beasties cause. Not only has the wall collapsed in two places, but the slope has become very destabilized. To my eyes, I would think the entire wall needs to be rebuilt. My husband doesn’t want to touch the first ten feet (+/-) but I think I may want to talk him into perhaps restacking at least some of the upper courses.

How do we rebuild just a portion of this? Can we even put a gravel backing/backfill on the rebuilt areas if there wasn’t any on the original?

I know we can do this, and it feels like a “good” project for us, but I’m just not sure where to start.

First few yards -- those are the "trunks" of the wintercreeper vines going up the face of the wall. This what my husband doesn't want to re-do.
https://imgur.com/XtvbmhS

The worst collapsed area
https://imgur.com/Fb3Cxyv

Last few yards, where it just kind-of melts into the ground...
https://imgur.com/Hh6wEYj

How do I get the photos embedded instead of linked?

Have you thought of learning how to do it?
There is plenty of info on the net about it.

Hi Rosa;  
To attach pictures they must already be on your computer.  
First you tap the attachment button , next to options on the lower left. A new screen pops up and you tap upload a file.
That will open your computers picture file.  Find the photo you want ,highlight it and save.
You can add a description below the photo at that time.
Add as many (up to 20) as you like.
Be aware that large format photo's will load slow if at all.

On to your rock project)
To start I know next to nothing about how to do this properly.
As John suggested reading up is just a good idea.

I see a bunch of hand digging OR much better I see a small track hoe at your house for a few days.
Dig it up, locate suitable rock, learn how to dry stack shale.  Backfill as needed. I sure make it sound easy don't I ....
It will only get worse if you do nothing.

Actually, I've been doing a lot of research, which is why I addressed this as a breast wall vs retaining wall, and wondering how I could get back fill in an area that didn't have it before. Knowing what to do isn't the same as knowing how to do it. My big question were where to start and how to integrate the old and new sections of the wall. I was hoping for advice such as, "Start at the low point of the collapsed area and work outward" or "Start at the end of the good section and gradually work down through the collapsed area"... Most of what I've read shows how to build one correctly from the beginning -- and what I've seen of repairs doesn't match what  have in my yard.

I was looking for advice based on experience.

I would definitely start at the largest good part and work from there. It is difficult to build a new wall into existing unless you have a surplus of varied stones so you can select just the right ones to fit in the gaps. Joining the existing low section will be much less involved.

The tall section of wall does not look structurally inspiring, and if you have any skill you can improve both its looks and longevity. Backfilling with gravel the whole length will also help, as well as building enough depth in the wall structure so it won't collapse. Do you have any more stone available, or is the existing wall all you can get to work with? How much batter is there in the existing wall? (How much does it slope back from bottom to top?) It should be at least 1" in 6" of height, or more if the stones are not ideal for wall building. The stones you show look quite good, flattish but rough for friction when built well.

The only section of the wall with batter is the short part going up the steps. It is also the only part that was constructed with mortar (which also needs replacing in many areas). Talking my husband into tearing down the wall in its entirety will take some doing... It really does need to be completely rebuilt -- it has no backfill and soil filters through it freely (not to mention making it easier for the groundhogs to dig there and push out stones, as they did). There is nothing resembling either a cap or a footer on this wall which I would like to correct.

Additional stones are readily available at landscape suppliers, albeit, not cheap. We will definitely need some replacement stones, as many have separated longitudinally.

I had sort-of envisioned repairing it in something of a ripple effect -- taking down about 10 feet at the beginning and moving down the line as we go. The other alternative would be by sections, I guess, but something tells me that getting sections go together and look right would not be easy. The two of us couldn't take down the whole thing at once and get it back up before massive erosion takes place. We may be healthy, but we're both over 60 and there are limits. Too bad we didn't have this project 10 years ago, when we had two teenage boys at home... Renting teenagers for manual labor is difficult these days.

Age should not weary you.
Just work at a pace that enables you to keep going as long as you want.
If you excavate far enough back during demolition you will not need to worry about erosion.
Then you can work on the whole length at once and back fill with gravel, blanket and soil as the wall rises.

Dry laid stone walls do not need footers in the usual sense. As long as the base course is deep enough going back into the slope, that base can be just about at ground level. It will shift a bit with the ground as it freezes and thaws, but if built well can flex and not deteriorate. I would consider a layer of well compacted gravel under the base course if the soil is not well drained or is loose like sand.

If there is not much traffic above the wall, I would not worry too much about capstones. It looks as if the ground will slope above the wall, and I would just save some larger, deeper stones for the top and cover their back edges with soil.

I have the impression that you don't have experience building stone walls. If you can commit to eventually rebuilding the whole wall, I would suggest starting at the lower end so you have practice by the time you get to the structurally more demanding tall end. You can take down just 10' or so at a time and proceed at your own pace. I find it good to prepare a stretch of base course so there is always a variety of places to put stones, and build up following that. Do not try to build a complete section of wall before starting the next section of base. You can always rob the next section of old wall as you find you need more stones, and you will find you need more A properly built wall more than a couple of feet high will need at least as many stones buried inside as on the face. All the stones that do not look good can be very useful in the core. There are plenty of videos on dry stone walling to give you the general principles and some details. The most important, and one I did not sufficiently follow in my early work, is to refrain from using all the nice long straight stones exposed on the face, but to put most of them running deep into the wall. It does not help to have a facade that is well reinforced by long stretchers if the whole face is not well tied back to the core.

You're quite right about us not having experience in stone wall building. That's why we're doing the research before we jump in. There are some controversies, though, and the vocabulary is not always the same. One site says to put landscape fabric between the wall and the aggregate behind it. Another says to put it between the soil and the aggregate. And yet another says Do Not Use Fabric! Some say a huge footer – you’ve said nearly no footer… No one says much on how often to use the deadman (tie?) stones, or if they should be even or staggered. And how deep should it go? The amount and type of backfill seems to differ, also. Some call for large rumble, some for gravel, and some for a combo. The current wall has nothing.  Some show the stones tilting slightly and others show them level.

What’s a newbie to think?

My thoughts for repairing (rebuilding!) our wall are:

1. Remove approx. 10 ft or more of old stonework from along the old wall at the low end
    a. Sort the stones for size as they come off
    b. Retain broken stones for backfill
2. Set my guidelines where I want the wall
3. Excavate the bare earth to the approx. twice the width of the wall, at a 1:6 slope
    a. This may be difficult due to the old wintercreeper vines and their roots
    b. This will be easy at the low end, but will get harder as we progress uphill
4. Excavate a nominal footer, about 4” deep from front of the wall to earth slope
5. Lay landscape fabric in footer and up the side of the earth slope
6. Fill the footer in with crushed stone
7. Lay the base course with the largest stones I have
8. Lay 2-3 more courses, backfilling as I go
    a. At the low end, the wall is approx. 6-8 courses
    b. Possibly raid the old wall ahead of the construction for needed stones
9. Insert deadman stones
    a. All on the same course, every other stone? Every third stone?
    b. Randomly?
10. When progressing forward, measure to ensure a batter of approx. 1:6
11. Stop the backfill approx. 6-8 inches from the top and use topsoil
12. Carefully place large stones on top as capstones

I still haven’t convinced my husband that we need to re-do the entire wall. He thinks we can’t get that done before the ground freezes. (We both work full time.)

Your plan sounds very reasonable to me. I agree that if you use landscape fabric, it needs to go between the earth and the backfill. If the earth is cohesive, it might not be so important to have the fabric; that is a matter for opinions. I can see no reason to put landscape fabric between backfill and wall. You want these to integrate, or else the backfill is purely weight pushing on the wall. Ideally the backfill has a good proportion of angular or flattish material. Round stones or gravel would be bad.

*edit* It may be that those recommending landscape fabric between backfill and wall stones are thinking of ordinary soil as backfill, and not a gravelly drainage/ anti-frost-heave layer.

A wall of any height needs to be more than one stone deep. A tall wall (5' or so) should probably be at least 2' deep into the slope at the base. Tie stones in random fieldstone walls need to go wherever they fit, scattered fairly evenly across the wall in both directions. I would put a tie at least every fourth stone in both directions, and possibly every second stone, depending on the character, size and shape of all the stones. The back of a drystone retaining wall or breast wall need not be smooth and continuous, merely have enough stones in contact and locked in place to support the back ends of tie stones. If you have good backfill with some flatter material, packing that in as you go would improve the strength.

The batter is a set quantity, usually 1:6 but could be 1:4 for stone that does not lock well. Some say to lay stones dead flat, but I think it is better to have the bedding slanted back a bit so the stones "want" to slip back into the slope. There is a retaining wall 2-3' high along the front lawn of a house near me that was laid dead flat with all thin flat squared stones (common in my area), and a couple of decades later the lawn has pushed the upper courses out several inches from freeze-thaw action, and it will eventually all collapse.

Good luck with rebuilding, and post pictures of your progress. As you go, you will develop a gap between the advancing new wall and the retreating end of the old wall. When you bring in new stone, you can close up that gap, and obviously trying to time it so you get as much stable wall as possible as winter approaches would be wise. The stability of a cut over winter depends on the character of the soil. If it has a fair amount of clay and stone, it may be fine as long as there is not a seep from above that keeps it moist from inside. Sandy or more pure clayey soils may not be stable.

Not sure how the project is progressing, but since I'm in the middle of a wall project too I thought I'd add my two cents.  

I've done a couple of these before, taller ones, and this time I'm doing multiple tiers with no more than 20" of rise with each, and at least that much horizontal spacing between the rises.  This is much more forgiving, and gives you the opportunity to have planting beds on each tier.  My soil is almost pure sand, with most of the rocks being fist size or smaller except for what we haul in.  I was lucky to have a neighbor with a lot of broken concrete from old patios and sidewalks, and that has a nice mix of flat edges and rough edges.  By keeping the rise of each tier lower I can make them wide at the base and sloped in toward the top, then cover the exposed face with more decorative natural stone.  A 20" rise means I only need fewer "decorative" stones stacked on each other for each tier and that makes keeping the whole business sturdy is tons easier.  

When I did a prior wall that was over 4 feet high in one solid face it was much harder to get the stone to lock in, even with a lot of tie into the bank and plenty of adjusting and redoing.  I ended up putting in about three times the work that I had expected, and the finished product needed yearly adjustments to set things right after each winter's heaving.  Since you're using a flat faced material you'll probably have an easier time of it, but even so that wall looks to get pretty high and you may want to think about working in a tier on the high end to make it a bit easier.  And I think it's almost always true that something like a terrace with some plantings in it or a piece of yard art to break up the face improves the look of the project when it's done.

Sorry for not answering for a while. We were out west visiting our son.

We haven't started the reconstruction yet, mainly due to my husband's wish to wait for cooler weather. (I fear he will then say it's too cold to start an outdoor project...!!)

Imaging my feelings to return from vacation to see a groundhog dive into the wall at its most collapsed spot. Luckily, it had not had the opportunity to complete a back exit, and we were able to dispatch it.

We may be looking at a full reconstruction in a few years, and tiers will definitely be part of it. Right now I'm having problems motivating my other half .. and he doesn't want me to start on it myself. I'm going to be ready to throw a full blown hissy fit if it's not started by October 1. (I'm the country girl and he's a city boy, and just doesn't seem to understand that you can't put a lot of things in nature "on hold" until you can get around to them.)

We've at least got vegetation on the area now to stop the soil erosion.

If you start at the short end, you can make it look like a modest, manageable project. Have a definite pause point so there is not too much dismantled wall to look messy. Then when he sees how nice the rebuilt part looks he may be on board to continue.