Dry Stone Walls – Principles of structurally sound construction (2018) | Hacker News Reader

Dry Stone Walls – Principles of structurally sound construction (2018)

masonrymagazine.com

186 pointsakakievich58 comments

I picked up a wonderful concept from a teenage summer spent dry stone walling in the Cotswolds.

When you pick up a stone from the pile, it MUST be placed on the wall. You either have to make it fit your intended spot through rotation or another adjustment, or you have to find another place on the wall for it. It CANNOT be placed back on the pile. I'm sure these rules are not adhered to that widely but they had some great benefits.

1. You eye your intended location very well, thinking in 3D. 2. You pick your stone very carefully. 3. You learn something each time the stone doesn't fit.

Before too long this restrictive practice becomes an advantage not a hindrance, and has many conceptual parallels with other physical and mental tasks. It's a beautiful thing.

This is an excellent rule for cleaning up (a room, a house, an office...): touch any given thing once at most.

In extreme cases, it doesn't work because you don't actually know where things are going to go, in which case a two-round approach is good: everything gets pulled out and sorted in round one, and things go to their destinations in round two.

It's interesting, I use precisely the opposite approach. I work in passes, each one intended to make the room cleaner as a whole but not necessarily finish any part of it.

For example, let's say I've had a big party and the kitchen is a mess. Step one might be to put the trash can in the center of the room and dispose of all visible debris. Step two might be to move all remaining small objects to one side of the room to improve visibility, then repeat the trash pass. Step three might then be to wipe down the counters, which are now clear of objects. Etc.

I tend to work in a similarly incremental way on programming tasks. Do you have a more "touch-once" approach there?

That's how I clean - pull everything out, assess, and put it all away. It's very efficient if you have enough space, but it drives people nuts because they see it as causing more of a mess.

An issue with this approach is it turns 'cleaning' into a time-consuming task that needs to be completed to avoid making the situation worse. That can cause some folks anxiety and require a building up of sufficient willpower to even begin the task.

Contrast that with a transaction-based approach to cleaning where an individual item is moved to it's destination place/state, then you move on to the next item. No middle state where things are worse, and you can stop at any time yet still have gained the benefit of any work completed to that point.

However, with the second approach it's key that everything has a suitable destination 'home' to be moved to. Often, that 'home' is the trash can :)

My wife attempts to use this method, but usually gets distracted at peak-messiness and things just end up worse off than they started.

No, you can't blame your wife for that method.

It was my method first.

She must have stolen it from me. ;)

I get scorned for doing it this way all the time!

Heap sort vs insertion sort.

Have also built stone walls in the Cotswolds, and I wouldn’t agree with you about not putting a stone you picked up back. Sometimes when you pick up from the pile you didn’t see part of the stone that makes it entirely unsuitable.

It’s better to pick the best stone to complement the space than try and jam something in that sorts of fits.

Have done it in the winter in a blizzard on the side of a hill - that was a painful experience, summer was much more enjoyable.

Edit to say: I realise now from your username we know each other - hope you are well! ;-)

Good to see you here, am well thank you and I hope likewise!

To your point, that's just the tradition I was told by the stonemason who built the walls I helped on.

There's a subtle art to pre-examining the stones before picking, it wasn't a case of if you touched it, it had to be picked up. It was more if you committed to this stone then make it work in this spot or another. There's always a place :-)

I see that rule as avoiding the search for perfection - otherwise you might spend hours picking up different stones and contemplating as if it were a jigsaw puzzle, when in actual fact there are 'solutions' everywhere.

"Perfect is the enemy of good."

I always saw this type of advice in the lens of: "this thing is heavy. I only want to pick it up once otherwise I will exhaust myself fairly quickly." I learned that from laying sod on a golf course one summer...

Laying a brick is like a chess move! Thank you!

This seems like it could be a (very) loose analogy for type-first programming. Before you start manipulating data (passing values to functions) you have to give careful thought to what data types you will need. If you do it right, there's far less rearranging (rummaging through the pile) needed later.

I use the same idea when stacking firewood.

I'm from Mallorca, a little Mediterranean island near Barcelona, and we have a great dry stone walls tradition there.

The people that do it are called margers in the local language. They never really disappeared, and they finally formed a guild a couple of years ago.

Here are some pictures if anyone is interested:

https://www.google.com/search?newwindow=1&biw=1745&bih=906&t...

https://www.google.com/search?q=margers+mallorca&newwindow=1...

I lived in Palma de Mallorca for 6 months. An enchanting place - my wife and I dream of moving back to the island someday and making a home in one of the small, old and hauntingly beautiful towns like Alcudia or Soller.

A 20 minute drive from Alcudia (which I visited today!) is Pollença, another beautiful town (not the nearby Port de Pollença, mind). It also doesn't get nearly as many tourists as Alcudia - if you get back to Mallorca, you should definitely have a visit!

I actually have family in Alcudia. :)

Another town you should check is Buynola. It has all the magic of the Tramuntana and not as expensive as Valldemossa or Deia.

Some of these are beautiful. Spent a lot of time looking at them & the trees while riding up the south side of Coll de Sóller.

There are reasonably valuable grants available to maintain existing walls. I think it's on a first come first served basis until the budget is spent (although you can probably jump the queue with a few targeted Euros!?)

Thank you, that was fascinating. It appears in the pictures that the stones are roughly uniform size. Is that natural or are they worked in someway before they are placed in the walls?

I have no idea. I imagine there is some degree of sorting and modification of the stones.

One of the pictures is from Skara Brae on Orkney - which is over 5000 years old, but its not even the oldest site on Orkney which is Knap of Howar which is ~700 years older:

https://en.wikipedia.org/wiki/Knap_of_Howar

https://en.wikipedia.org/wiki/Skara_Brae

One of the ancient sites on Orkney did have some relatively recent problem with vandalism though:

http://www.orkneyjar.com/history/maeshowe/maeshrunes.htm

relatively recent :) Everything is relative.

In the Bluegrass region of Kentucky [0], there is a rich heritage of stone fences, which are associated with thoroughbred horse farms, but they exist throughout the area because of the abundance of limestone rock available. It is one of the highest concentrations of dry rock structures in the US [1].

There is a similar organization, the Dry Stone Conservancy [2], that runs a similar certification program and workshops, but more focused on the specific needs of the area, including conservancy.

[0] - https://en.wikipedia.org/wiki/Bluegrass_region

[1] - https://uknowledge.uky.edu/upk_cultural_history/3/

[2] - https://www.drystone.org

At Donner Pass in California there is the Chinese Wall. A dry stone wall built in the 1860's to carry to the Transcontinental Rail Road. It looks in perfect condition after 150 years.

It's short 1/4 mile hike from the road.

http://cprr.org/Museum/Sierra_Grade_8-2003/Donner_Pass-Summi...

http://www.calexplornia.com/china-wall-truckees-memorial-chi...

Eh, the fences are nice and I love Lexington, but I would credit the fences mostly to the legacy of slavery. Lots of places have limestone. Those fences didn't build themselves. It's great that people nowadays are conserving them, but I haven't seen many new fences down there.

This is actually a huge misconception and false. The majority of fences were built by immigrant Irish stonemasons, although it is obvious that slave labor probably played some role in this. The style of stone fence was directly imported from Ulster & Northern Ireland, with Irish immigrants. If you'd like to know more about the history of the fences, and more specifically, the masons that built them, the authoritative source is "Rock Fences of Kentucky" [0].

That's not to say that slavery does not play a role in the history of the area (and the entire country), but much of the heritage of the stone fences has little to do with slavery or slave labor. Post emancipation, the number of freedmen stonemasons slowly grew and displaced Irish stonemasons.

[0] - https://books.google.com/books?id=UDHQjDJ677MC&pg=PA84&sourc...

That's a great link; thanks! I've heard the slave explanation from numerous people at various stud farms, but not everything we hear is true...

Still, southern Missouri has lots of limestone (it's "the cave state"), and had lots of Irish and Scottish immigrants, and I can think of precisely one "slave fence" in the whole state. If the difference wasn't limestone, and it wasn't Irishmen, maybe it was that Kentucky had lots of rich tobacco plantation owners, and Missouri didn't.

Famous historical and archeological sites with extensive dry stone walling:

The megalithic acropolis and vaulted tombs at Mycenae:

https://en.wikipedia.org/wiki/Mycenae

The megalithic Nuraghe forts in Sardinia, also with vaulted ceilings:

https://en.wikipedia.org/wiki/Nuraghe

Osaka castle, in Japan (the base wall is made of dry stone):

https://en.wikipedia.org/wiki/Osaka_Castle

The central buildings in Macchu Pitchu (hand-cut dry stone, called ashlar):

https://en.wikipedia.org/wiki/Machu_Picchu

>There are examples of dry stonewalls and structures that date back 5000 years and are still standing today. Nearly anywhere in the world where stone of suitable sizes was plentiful, walls were built.

What I'd like to know is are there any patterns to where the second is true, but said walls haven't lasted thousands of years like the first sentence says? Are there places where ancient stone structures could have been built, but are no longer standing for reasons other than human interference? Perhaps they fail to survive more in earthquake prone areas, or when there is heavy vegetation that pushes roots through the rocks?

I have seen plenty of collapsed dry stone walls.

Often the reason for the collapse isn't obvious - I suspect rather than a catastrophic event, it's more that the stones right on the top of the wall aren't held in by interlocking and friction as well as the other stones, so storms and animals can dislodge them. Plants growing in the top of the wall can knock stones off too.

If plant matter gets inside the wall, pools of water can form between stones, which then freezes and pushes stones apart and cracks them.

Do that for 2000 years, and the walls turn into a scattered line of stones in the ground 30 feet wide.

> rather than a catastrophic event

I'll give you catastrophic. Quite a few years ago me and some mates were camping in a field at night and a lady misjudged a turn and took her car through the dry stone wall. The car threw hefty blocks for an astonishing distance. What was odder was that after the initial smash I could hear heavy thuds as blocks dropped from the sky for what seemed to be up to 10 seconds. Far, far too many seconds to be credible, but that's what I noticed at the time.

Being dark we heard it but didn't see it happen. The full glory was revealed next morning.

If that wall hadn't been in the way the car would have gone all over our tents - and us.

We owe some anonymous derbyshire dry waller a lot of beer for putting it in the way.

(The lady was uninjured if extremely shocked)

That's interesting. I wonder if another factor is a wide variation in the level of skill used to build the walls. It's easy for a complete beginner to start building dry stone walls based on a limited amount of information - and using only materials found on site. Those walls might last the lifetime of the builder, but are less likely to hold up to stress over the ages.

I don't know about thousands of years off hand, but if you spend some time in New England you will see the truth to the poet's words:

  Something there is that doesn't love a wall,
  That sends the frozen-ground-swell under it,
  And spills the upper boulders in the sun;
  And makes gaps even two can pass abreast.

Many, most, all of the dry stone walls once in pasture and now in forest used to be straight, neatly stacked walls, and are now linear heaps that only outline and no longer divide old paddocks.

While Frost is beautifully right here, of course, there is a mild irony in that many of the rocks in New England walls were brought there by repeated glaciation, so cold both made the walls possible, and, as frost-heave, both surfaces buried rocks, and breaks down dry walls made with the generally rounded glacial rocks.

A secondary cause for spilling the upper boulders is the behavior of herds of dairy cattle, with each cow reaching over the wall to reach that one extra blade of tasty grass, with eventual wall collapse.

I have a friend there and they say it's pretty common to hire someone to restack them

The title of the poem is, in fact, "Mending Wall", and the overall subject is the yearly work to maintain the stone walls and musing on the necessity of the work.

In a similar vein, I like this youtube channel: https://www.youtube.com/channel/UC1By4oBZiv9u8qnkcdCgdqw

My favorite videos are the ones where he walks around a famous stone structure and talks about all the craftsmanship that goes into them.

Thought initially this was from the UK’s National Stone Centre in Wirksworth, Derbyshire [1]. It used to be a visitor attraction - not sure if that’s still the case [1] http://www.nationalstonecentre.org.uk/

Is there an optimum somewhere between a fully-mortared wall and a drystone wall? i.e. mortar which gives some reinforcement but also allows rain or groundwater to run out?

You sometimes see a drystone wall that has a mortared top. Here's one example: https://www.google.co.uk/maps/@51.8862561,-2.0573352,3a,24.1...

Just down the road there's another, less attractive, example: https://www.google.co.uk/maps/@51.885003,-2.0568722,3a,46.6y...

Use natural hydraulic lime mortar, which is flexible and breathes.

I'm hoping to build one of these next year, along the 2' slope in my front yard that's annoying to mow and won't grow grass the same as the rest of the yard. It'd be cheaper and easier to do with manufactured blocks, but my spouse and I think a dry stone wall will look far better with our 100+ year old stucco/stone bungalow. And it'll be more engaging to build.

Just be careful if you're putting fill behind the wall--like all retaining walls these aren't really designed to 'hold back' anything. Their strength comes in compression, not lateral loads. At a bare minimum make sure you put a layer of crushed rock next to the wall, separating the dirt from the wall. This will mitigate water and decomposing plant material from resting against wall swelling and causing the wall to be shoved apart.

Fully agree. If you want a cheap(er than concrete blocks) retaining wall that requires no special tools to assemble use tires. Unreinforced stone is great for getting all the stone out of the field you need to plow though.

> aren't really designed to 'hold back' anything

Don't tell the Europeans that! You see them throughout the med:

https://www.google.com/search?q=stone+terraces+majorca&prmd=...

Those aren't designed to stop the hillside from sliding. They're there to stop erosion and crumbling at the edge. If those hillsides want to move, those walls will not hold them back.

Yep. My father was a landscaper, and I built a number of railroad tie retaining walls, so I get the load problems. It shouldn't be a problem, as the area already has a good gap.

A friend of mine did a practical course on building dry stone walls recently. She was taught various building styles from different parts of the UK. There's more than one way to pile a rock!

Sorry if too OT, but I wished we used stuff like this more in the US. Stick construction is really bad at noise and vibration isolation.

Damn you, HN. I have enough hobbies already, plus I am old. Now I want to build a dry stone wall somewhere.

Not sure old counts, Churchill had brick laying as hobby into his sixties. He wrote to Stanley Baldwin in 1927: "I have had a delightful month—building a cottage and dictating a book. 200 bricks and 2,000 words per day." He started with garden walls.

Have fun with your new hobby. :)

https://www.reddit.com/r/HistoryPorn/comments/708sxb/winston...

What a lovely answer. Thank you. I am in fact working on a book and a compiler at the moment!

There are many dry stone (lava) structures on the Hawaiian islands.

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