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Stone Wall Restoration
Here in New England a common request that we receive is to do stone wall restoration, or to rebuild existing stone walls. Most commonly these are drystack retaining walls that have deteriorated over time and need to be taken down and rebuilt. Fortunately the stone is perfectly re-usable, so stone wall restorations are comparatively less in cost than building new.
Why do stone walls need restoration?
In our experience the stone walls built in this area within the last 100 years or so were done without much attention to base material, backfill, or drainage. When we dismantle older stone walls, what we usually find is dirt backfill mixed with stone. Dirt or soil does not drain well, it holds moisture and will expand with freeze/thaw cycles. Soil also promotes plant growth and invites vegetation and roots.
Soil erodes and overtime will rinse through the stones towards the front of the wall. As it mixes with the face stones, the freeze/thaw and root growth will cause more and more movement in the stones. Eventually stones fall off the wall, plants and soil show through the front, and/or portions of the wall collapse altogether. At that point there isn’t much one can do to repair the wall other than dismantle the wall (or just a section) and rebuild.
Fortunately the stones can all be re-used, and a rebuild poses a great opportunity to re-design the walls in a favorable way. This will often mean pushing the wall back to create more space, raising the height to create more level ground above, adding stairways for access, etc.
Below are photos of various walls that show the conditions before restoration. As you can see, these walls are not the most visually appealing, and some of them are starting to deteriorate or collapse.
Restoring the Wall:
Excavation + Prep
To restore a fieldstone wall we first dismantle the wall and save the existing fieldstone. The stone will go into a pile nearby while we excavate the base and backing. For the base we make sure to excavate deep enough until we find solid/well draining subsoils. We then compact the subsoils and add a layer of compacted crushed stone to set our base stones in.
Behind the wall we excavate far enough back provide room for clean stone backfill. A general rule of thumb is that the thickness of the wall should be at a very minimum 1/2 of the height. But more width is better whenever possible. At the back of the excavation we install heavy duty filter fabric. This is a construction grade fabric that allows water to flow through but does not allow dirt or roots. This means dirt/plants will never migrate or mix into the backfill or wallstone.
We haul away excavated soil or stockpile on site for grading behind the wall. Often in restoring a stone wall we will raise the height to achieve a more favorable grade behind and so saving the fill is useful.
Take a look at the following stone wall restorations in various stages of excavation or prep:
Building The Wall:
To build the wall we start with the largest stones and set the base course. These stones are the heaviest and sturdiest and form a solid foundation on which to build the rest. Next we stack up the face. We build the face of the wall by carefully stacking the stones with the bulk of the stone tying back into the wall. Each stone should be stacked on top of the joint below for added strength. Additionally, we use smaller stone or “pinning” to shim and lock the stones in place. We backfill with more fieldstone, rubble, smaller stones, etc. We don’t use gravel or crushed stone behind the wall because it is too small and can flow or erode through the face of the wall. We want our backfill to be tightly packed stone or rubble that is solid, adds mass to the wall, but drains water freely.
In most cases, all the material we need to bring to the site is a bit of crushed stone for the base, and additional backfill to replace any dirt we have removed. We may also bring supplemental fieldstone to mix in with the existing. This is necessary whenever the wall may be increasing in size.
As we reach the desired height we stretch a cap line, and use our largest, flattest stones for the top. These large flat stones help hold everything in place, and give the wall a clean finish. The result is a sharp looking and long lasting New England stone wall.
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How to Build A New England Stone Wall
Traditional New England Stone walls are a classic feature of our landscape. They represent a long history of agriculture in this country, and are still built today for a variety of practical and decorative reasons. Building a New England stone wall may be hard work, but it is fairly intuitive and doesn’t require highly specialized knowledge or skills. Anyone can do it who has some work ethic, persistence, and wants to try their hand at the long standing tradition of dry stone walling in New England.
If you’re ready to take on the task, read below for a step-by-step guide on building your Traditional New England Stone Wall.
Finding the Stone
One the most satisfying and affordable ways to find stone for a New England Stone Wall is to salvage stone from your own property. This is exactly how stone walls were built in the past, and many properties in New England still have old fallen down and buried stone walls and piles. Otherwise, stone can come up from excavations or construction projects, or can be gathered overtime from gardening or landscaping.
If you don’t have stone on your property, New England Fieldstone can be purchased from a local stoneyard or landscape supplier. The general rule is that the more the stone has been handled or sorted, the higher the cost will be.
The cheapest stone you may find is fieldstone that is a byproduct of excavations or loam screenings. Some landscape yards will have a pile of stone that is more or less waste to them, and they will sell it cheaply. This stone will be completely unsorted and may have sticks and roots and some other materials mixed in. If you’re on a budget, and don’t mind picking through the piles then this is a good option.
After that there will be material bins or piles of bulk fieldstone. Bulk fieldstone is loaded by a bucket machine into a dump truck, and is priced by the ton or yard. The bulk fieldstone comes mixed, or has been sorted into piles of different shapes/sizes. Some types of masons much prefer the sorted stone, but for traditional drystone walling the full mix of sizes and shapes is often the best.
After the bulk supply you will find New England Fieldstone packed on to pallets. This stone has been further hand selected, and can be delivered on a forklift. This means the pallets can be put down exactly where you want , and placed in different spots down the length of the wall. This may be worth it to someone who doesn’t have a machine, and doesn’t want to move a dump truck load of stone by hand.
Weathered vs Unweather Stone
Weathered stone is another distinction you will find. Weathered stone has been out of the ground longer and has grayed in color, has a rougher more eroded surface, and may have lichen and moss. This differs from freshly excavated stone which can be smoother and more brown/tan in color.
How much stone do you need?
Figuring out how much stone to use is a simple formula. First calculate the volume of the wall by multiplying length x width x height (in feet). This will give you cubic feet which you then divide by 27 to arrive at cubic yards. If you are buying stone by the truckload then a cubic yard measurement may be the most useful, or if by the ton there is approximately 1.5 tons of fieldstone in each cubic yard. When dealing with truck loads of stone these are rough measurements and estimations, and it is rare you will be able to fit every single stone into the wall. So expect that you may come up short or have excess stone at the end.
What tools do you need?
To build a Traditional New England Stone Wall you will need some basic tools which you may already have, or can find at most any hardware store. These tools are:
wheelbarrow or 2-wheel dolly (moving material)
shovel, pick-ax, steel rake (base prep)
tamper (compacting the base)
6′ prybar (moving and adjusting base stones)
sledge hammer (breaking large rocks)
mini sledge hammer or rock hammer (trimming smaller stones)
gloves (saving your fingers)
Preparing the Wall:
Once you have sourced your stone and gathered your tools, the next step is to plan your wall and prepare the area. To prepare the area for your New England Stone Wall it is best to excavate the footprint to remove any organic topsoil. In many areas that aren’t forested, the top soil is not very thick and 8″-10″ of excavation will do. Topsoil does not compact well, holds water and gets muddy so doesn’t provide a sturdy base. The goal is to remove the topsoil until you find the sandier/stonier non-organic subsoils which do compact and drain well.
Sometimes you instead find clay subsoil. Clay will also pack down very hard when dry, but, holds moisture and can get very soft and spongy when saturated. If this is the case then a drainage or an outlet for water at the bottom of your excavation is a good practice.
Once excavated you can start building your stone wall from below grade directly on top of the hardpacked subsoil, or you can fill the base with crushed stone or gravel. The gravel can be compacted to form a solid base, and provides a permeable base layer for water to drain through and keep frost/heave forces away from the stones.
Building the Wall:
Setting the Base
To build the wall first set set stakes at either end and stretch a string line to follow. If the wall is to curve, then step back and eyeball your curve periodically or paint a line on the ground to follow. If you want to be precise you can screw bendable pieces of plastic tubing to stakes and follow those. A 1/2″ electrical conduit makes for a good bendable line.
Select your largest stones first and lay them to form the base course. The larger stones create a solid foundation but also these are the stones that you can’t lift off the ground. So getting these stones into the wall while you still can is your best use of your material. Set each base stone with the desired face out, but keep in mind that wall is sturdiest when the bulk of the stone ties into the center of wall. Keep small stones or “pinning” on hand to shim the larger stones so they lock in place.
At this stage a large 6′ prybar is your best friend. This can be used to push and adjust stones, lift and level them, and tamp the surrounding earth or gravel so that they sit sturdily. The large sledge hammer may also be used at this stage to adjust stones, or break/shape large stones that need it.
Once you’ve set both faces of the wall, pack the middle with small stones or “hearting”. The more densely you pack the stones, the more mass the wall will have and the sturdier it will be.
Building the Face
After the base course is in, you can start building up the face. Again lay the stones so that most of their mass tie back into the wall, and use smaller stones to shim around them so they lock in place and don’t wobble to the touch. Laying the stones somewhat level and in courses helps keep the wall organized and makes setting the next stone on top easier since you’ve created a flat open space above. Leveling your string line and moving it up as you build the wall will help with coursing. Every once in a while step back from the wall to view it from a distance and make sure you are using a good mix of stones and following your lines. At this stage you may use the mini sledge hammer, rock hammer, rock pick, or any variety of walling hammer. These smaller hammers can be used to trim and shape stones, and tap stones and shims into place.
The Cheek Ends
The ends of the wall or the “cheek ends” are the hardest part. Here you will need to find corners, and must take a lot of care to make it sturdy. From the very start of the process you should be keeping an eye out for good corner stones and saving them for the ends.
Capping the Wall
As you get closer to the top set the string line to the desired height and start planning your cap. A traditional New England Stone Wall is about 30″ tall which is about mid-thigh for an average man. The reason for this is that mid-thigh is where one’s hands hang to. Meaning, you can lift a stone to that height using only your lower body and without bending your elbows. A mid-thigh high wall is also just high enough that stepping up onto isn’t easy, so serves as an effective or at least non-inviting barrier. If 30″ is the average, anything higher is a more imposing wall, while lower walls become more quaint and decorative.
To cap the wall it is best to save your largest, flattest stones. These large flat stones will create a tidy cap but will also help hold everything in place. The bigger the stone, the harder it will be to move, so it serves to lock in all the smaller stones below. Also if people are going to want to sit or walk on the wall they will naturally gravitate towards the large flat stones to sit or step on, and avoid the smaller stones that could move.
Pick out your biggest cap stones first and find where they will fit, and then fill in smaller cap stones around them. Keep small flat stones on hand to shim the caps up to meet the line. It’s rare that you will find the absolute perfect fit, so using smaller stones to shim the caps up to the desired height is an easier way of reaching a precise height.
How much wall can you lay in a day?
The average worker, moving at a good pace for 8 hours should be able to lay about 8′ of double sided, 2.5′ high wall in day. This equals about 2 tons of stone to lift and set per day.
What to watch out for?
One thing to watch out for in planning your wall are underground utilities. Public utilities that come from the street can be electric, gas, water, sewer. Water and sewer lines should be at least 3′ deep so shouldn’t be a concern but sometimes older houses can surprise you. Electric and Gas lines only need to be 18″ deep and could get punctured by a prybar or easily severed by machinery. When digging take caution and look out for fresh sand or caution tape, this will signify utilities below. Dig Safe is a free service that will come and mark any public utilities coming from the street. But they won’t mark any private utilities that are coming back out from your house.
Stone walling is hard work and your back, legs, arms, hands will be sore at the end of the day. Take care to lift stones with a proper form by squatting down and using your legs instead of bending over and using only your lower back. A good method of insuring proper lifting form is to squat down and then lift your chin up and look at the sky. This motion will force you to lock in your lower back and lift with your legs. Over the course of a day you may lift 4000lbs of stone – so do it the right way to avoid undue wear or injury.
Crushing a finger is a very common and painful injury when building New England Stone Walls. Catching your fingertip between two rocks will ruin your day, and if the nail comes off it can take about 6 months to fully grow back.
To avoid finger crushing always be careful and aware of where you fingers are, and where the stone might shift or fall to when setting them. When lifting stones with the help of another person make sure you lift at the same time and don’t tip the other side of the stone onto the other person’s finger or vise versa. In stone walling, gloves protect your hands from getting rough, dirty, scratched, and calloused. You may not care about those things, but what gloves really do are help prevent finger crushing. That little extra separation and reduced friction will allow you to slip your finger out of the glove and escape when you feel it getting pinched. Without a glove, as soon as you feel it, it’ll be too late and you may have a long wait for a new fingernail.
Still crushed a fingernail? Go to the ER or clinic and have them put a hole in the nail to relieve the blood and pressure buildup. They’ll use a small drill or a red hot poker to melt through your nail. It hurts for a moment but is well worth trying to save the nail, and will save you days of throbbing pain.
Building a traditional New England Stone Wall is a satisfying experience. You use your body, simple tools, and local, natural resources to carry on an ancient practice. The work is straightforward, intuitive, and grounding. You get to see your progress clearly at the end of each day, and get to enjoy the fruits of your labor for many years thereafter. Like anything you will get better with practice, but it doesn’t take any extraordinary skill or knowledge to get started. Feeling the weight of a stone and how it will sit solidly is almost a natural instinct and is something people have been drawn to for thousands of years.
One of the quintessential features of our New England landscape is the rambling stone wall. Gray and lichen covered, these stone walls meander through the woods, and line our roadways and fields. They are so common place one may almost dismiss them as some natural occurrence that has always been, but in reality New England stone walls carry a long history and represent the monumental human effort that went into the farming and building of this country.
The Early Years
Contrary to what you might believe, stone walls were not common in the earlier years of New England settlement. When Europeans first arrived in New England, the land was densely forested and covered with a thick layer of topsoil and humus. Thousands of years of forest growth and decay had deposited the thick layer of organic earth, burying the more stoney glacial soils deep below. Although the first settlers had much to contend with, stoney fields were not one of them.
Along with an absence of stone there was an abundance of trees. Wood was light, easy to work with, and plentiful. This meant that wood was used predominantly for building purposes including the fences that surrounded properties to pen animals, protect crops, and mark property lines.
The Revolutionary Era
It wasn’t until about the time of the Revolutionary War that mass stone wall production began, and hundreds of thousands of miles of stone wall were built in New England.
By this time private farming had become the predominate practice, and families spread out throughout New England to work the land. As they worked and farmed the land, the forests were clear cut for pasture, and the earth turned up and plowed.
At the time wood was a very valuable resource. People used wood to build houses, heat homes, boil sap and for other industrial production. The average family burned 35 cords of wood per year for heat and cooking alone, and by the mid 1800’s 75% of New England was clear cut.* Without the forest and natural vegetation to hold and replenish the topsoil, the soil eroded and eventually exposed the more stoney glacial soils below.
After erosion, frost heave played a major role in bringing stones to the surface. Without the thick layer of well insulating topsoil, the frost line now reached the stoney soils below and they became subject to the freeze/thaw cycles. Now, stones seemed to grow out of the ground as frost heave pushed and pulled millions of stones to the surface each year.
Lastly, post Revolutionary War saw a new national optimism and a subsequent baby boom. As families grew and turned their attention towards their homes and farms, there was now enough labor available to take on the task of moving the copious amount of stone that was appearing in fields all over.
Building the Walls
New England stone wall at Old North Bridge in Concord, MA by Robert Thorsen
The stone walls of New England were not built all at once, but rather grew and evolved over the years. Whenever necessity arose, or spare time permitted, farmers gathered stones and moved them from the growing fields to the next easiest location. Sometimes that was a pile, but more often it was the edge of the field. The earlier stone walls were most commonly ‘dumped walls’. These stone walls were more or less refuse piles, or simply the most convenient place to dump excess material. Other refuse, like stumps and brush, would also have been dumped at the edges of the field. Along with the stone, this formed a barrier or delineation from the surrounding forest or neighboring fields.
Before tractors and machinery, stone was transported on carts or a wooden sled called a ‘stone boat’. The stone boat was low to the ground so easy to roll larger stones onto, and draft animals were used to drag them.
Each spring more and more stone accumulated in the fields, and was transported to the edge, and over the years the amount of stone grew. Eventually as wealth and pride in one’s home/farm grew as well, time was spent stacking the stone into more organized and attractive stone walls. “Stone by Stone” author Robert Thorson estimates that by 1871 there were close to 250,000 miles of stone walls, enough to stretch from the earth to the moon, or enough to circle the globe 10 times. If an average worker can stack about 10′ of wall in day, these walls represent over 100 million man hours of labor.
As the farming industry faded in America, farms were abandoned, the forest retook the land, but the stone walls remained. To this day you can scarcely walk a mile through forested land without stumbling across and an old lichen covered stone wall – the last remaining relic of the rolling farmlands that were once there.
Now days, we still build New England stone walls for a variety of reasons. They create an attractive barrier to surround ones property which can mark property lines, contain pets and children, obstruct errant vehicles, and reduce road noise. Weathered New England fieldstone is now a valuable material that we painstakingly reclaim from the meandering, overgrown walls in the woods, and re-use to build fieldstone walls and features of all sorts.
It is a comfort to know that the stones being organized and stacked in one’s yard now are the very same stones that were once pried up with iron bars, dragged across the fields on wooden sleds, and stacked and handled by generations of fellow countrymen before us. And although technology has progressed, in the end the same two hands are stacking stone by stone the very same way it has always been.