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CHAPTER 1

Kinds of Stone

The next step is finding stone. Most everything I've read about building with stone assumes you have a sufficient supply of "good," easy-to-build-with stones with three or four flat sides. And they suggest that if you don't have enough good stone lying around you can buy or quarry it or dress rounded stones flat.

Use What's There

Quarrying by hand and dressing stone is devilishly hard work, and paying to have rock trucked any distance is expensive. Certainly, good stones are easier to build with and make a classier looking wall. But I'd say, if some or all of the stones you have are in the "not-so-good" category, go ahead and plan to use them. We'll get into using both kinds for wall construction.

In New England, much of the Midwest, the Lake States, and parts of the Northwest, the ancient glaciers either deposited or exposed many types of stone suitable for building purposes.

The glacial deposits, composed of sand and gravel, form the till plains, moraines, eskers, and drumlins. In addition, there are huge boulders, often referred to as glacial erratics, which litter the fields, forests, and streambeds — all giving the glaciated countryside of these regions their topographical character and form.

There Types of Stone

In some places, the mile-thick, ancient ice sheet had scoured, gouged, and literally plowed away the earth's mantle; leaving the area's bedrock exposed in its retreating wake. Today, one can find many different kinds of stone for building purposes. There are three basic types — igneous, sedimentary, and metamorphic.

Igneous Rocks

Igneous rocks result from the cooling and solidification of hot liquid rock. Much of it was formed deep in the earth, and it is the hardest, densest kind of rock to be found. An example is granite — the most common intrusive igneous rock, meaning it was cooled and solidified at great depth. This is opposed to extrusive igneous rock, such as basalt, which cooled and solidified at the earth's surface.

Sedimentary Rocks

Sedimentary rock is produced by the consolidation of sediments that have been formed by weathering and piled up by any of the agents of erosion (wind, water). Thus, the most noticeable feature of sedimentary rocks is their layering. However, many sedimentary rocks preserve features or objects associated with the sediments, such as shells, bones, invertebrate animals, plants, footprints, ripple marks, and mud cracks. In other words, sedimentary rocks often are fossilized, and include such common stones as sandstone, limestone, shale, and conglomerate.

Metamorphic Rocks

Metamorphic rocks are the result of either sedimentary or igneous types being modified by pressure, heat, and chemically active solutions. Such rocks are characteristically banded or layered in some fashion. Some common metamorphic rocks are marble, slate, schist, and gneiss. Marble is metamorphosed limestone, slate was originally shale, and schist and gneiss are modified granite.

Some Will Split

Probably the best wall stones come from hard shales and schists — rock types that developed flat cleavage planes during metamorphism so they split out into layers with flat tops and bottoms. Many will break naturally into stones with flat sides as well. Others may not come with good flat faces, but can be dressed quite easily. I've worked with some metamorphics that split almost as easy as a block of wood.

Hardest to build with are igneous stones found in fields or running water. Glacial action or gradual erosion in a stream has tended to round even those very dense and hard rocks. Though nearly all rock has a "grain," or a tendency to split along a fairly flat place, finding the grain in granite and the like is difficult, and splitting faces off small rocks takes more time and effort than it is worth.

Sedimentary Rocks Wear Faster

Sedimentary rock formations, having been laid down in sheets, tend to occur in layers — properly called strata. Most are relatively soft and easily split or cut by nature or a quarrier into good building stone. But they also wear faster than other kinds of rock. Wind-borne particles will wear down sandstone in time, and limestone gradually gets eaten away by the natural acids in rain water. A sandstone or limestone wall might not hold up for more than ten or twelve thousand years.

Marble and Slate

Besides its good breaking tendencies, metamorphic rock is usually durable — even though it is often soft and easily worked. Marble is the traditional medium of sculptors and much ancient Greek and Egyptian marble sculpture has withstood wind and rain for thousands of years. Another metamorphic, slate, was used for gravestones by the earliest settlers in America. Go to an old colonial graveyard and notice it is the slate stones whose inscriptions are still sharp and clear. Other markers, igneous rock included, have worn nearly flat.

Other Materials

In some areas, of course there is little or no exposed rock. In many of the Plains states you will have to go to a river valley or excavated quarry to find stone. In the Florida Keys I've seen dandy walls made from coral chunks. And in parts of the Southwest folks have to make their own — soil, straw and water packed in molds and dried in the sun to adobe. It all makes a good wall.

Sources of Stone

Lacking a supply of stones on your own place and not wanting to buy them, you can look several places. Perhaps another landowner will let you haul off rocks from his walls or abandoned stone buildings. Rock ramps, cellars, and foundations left after an old house or barn has burned down provide one of the best "good" stone sources you can find. Often these old cellar holes are dangerous or an eyesore, and owners are glad to have part of the demolition or fill-in job done free.

Construction sites often provide excellent flat-sided rock picking, especially where new highways are being dynamited through the hilly country. Streams, rivers, many lakes and the seashore in some places are good sources for frost-split or water-rounded stones. And you'll find that stones only weigh half as much moved under water.

Quarries and Pits

If there are a good many old stone buildings or foundations in your area, you may find abandoned quarries or gravel pits scattered through the countryside that were dug by the original stone-builders. Ask around, or consult a U.S. Geological Survey topographical map. Abandoned and active quarries and gravel pits are shown on such detailed maps.

Look on Maps

If you are unfamiliar with topo maps, they are a must for the stone-builder in search of material. A topo map is essentially a detailed rendering of an area covering 49 to 70 square miles called a quadrangle. The map shows roads, buildings, streams, lakes or ponds, swamps, contours, and elevations (in 10-foot intervals), as well as quarries and gravel pits.

Each quadrangle is named for a town or important feature within the area covered, and each state is divided into numerous "quads." To find out which quadrangle you need, you must first obtain an index, which is a map of the state showing the quad divisions and their names. To order topo maps and a state index, call or visit online:

U.S. Geological Survey

1-888-ASK-USGS (1-888-275-8747)

Tell About Stones

Also, some quadrangles have been mapped geologically. That is, there are special issues of certain quads which have been colored to show glacial and/or bedrock features of the 49- to 70-square mile area. It is worthwhile to inquire about such quadrangles because they give detailed information on the type of stone you are likely to find, where large boulders are likely to occur (if a glaciated area), and where bedrock is exposed. Not all quads have been so mapped, however.

On a broader scale, there are some states which have maps showing its geological features. The State of Ohio, for example, has a state map of its bedrock geology and another of its glacial features. You should check with your state geological survey to find out if such maps are available for your state. If there is no such governmental body in your area, then inquire about these maps to the U.S. Geological Survey at the addresses previously given.

Other Sources

Finally, you may have to buy stone or resort to digging, quarrying, or picking up your own from fields and creek beds as nature provides them. Operating quarries are often listed in the yellow pages of your telephone directory. In addition to map sources and the state geological survey, you may have a geology department of a college or university nearby that can give you further information, especially on what kind of rock is available and how to obtain permission to quarry or dig your own stone.

We will go briefly into quarrying later on; for now, let's assume you have your stones at hand. The principles of wall building are pretty much the same no matter what kind of rocks you use. Let's build a section of that basic three-by-two-foot wall to get the essentials down pat.

Equipment

Cart Is Useful

I've found one of the handiest pieces of wall-building equipment — better than a wheel barrow — to be one of those high-wheeled, box-shaped garden carts. You can tip one up on its square end and just roll the stones in. Don't overload it, as I did once, and have a wheel collapse on you. Used sensibly, the carts save much lifting, and you can run larger stones up planks to the wall top with one.

Other tools include a yardstick, a hank of stout cord, several stakes a foot or so longer than the wall is to be high, a line level to go on the cord, a mason's level and perhaps a long and true board to tie it to, plus a good-digging spade.

For the Big Ones

To move larger rocks around, you'll need a long (five feet or more) steel crowbar, and a smaller crowbar, or pinch bar, that has one end curved. Another device is the hoe/pic. This tool is 26 inches long, weighs about 4 pounds, and is somewhat expensive (about $17.00). However, it has many uses — pick, wedge, prybar, and a hoe. Its versatility goes beyond the use in stone wall building and it has a decided advantage over conventional prybars when one must dig large boulders that are embedded in the ground. You'll also need a collection of thick planks and short lengths of 1 ½ or 2-inch iron pipe to serve as rollers if you are working with really big stones.

Goggles Needed

If you plan to do any trimming or dressing of stones, get a pair of safety goggles. Rock can splinter into razor-sharp fragments, and even a dull chunk in an eye can mean trouble. Be sure the goggles are well ventilated so they won't fog up on you during a hot day's work.

Handy Tool

For trimming and dressing you should have a set of mason's or geologist's hammers and chisels. These come in a variety of widths and shapes, and are used mainly for scoring and splitting both brick and stone. A relatively new tool available to stone-builders is the rockhound's gad-pry bar (cost about $7.00). Used with a heavy crack hammer, this 18-inch tool easily opens seams and crevices in stone. It has two hammering faces (see tool illustration) that permit you to drive the bar down into a seam, and then to drive it to the side to force the crack or seam apart.

Rock Chisel

If you plan to do any drilling or carving in the rock, an artist's supply store can offer you a selection of rock sculptor's tools. For drilling, you'll need a high-tempered rock chisel with a cutting head ¾ to ½-inch wide. It will be forged in a dull "V" shape and will serve for carving, too.

Types of Hammers

Hammers come in two types. One kind has one flat head and the other in a wedge shape — this is the traditional stone mason's hammer. The other, a Bush hammer, has a flat, toothed head for really getting a purchase on a piece of rock. You can also get a lightweight mason's hammer shaped like a geologist's pick. It is for more delicate work and has a small pounding face and a long, thin chipping blade on the other side. Special heavy-duty tools will be mentioned when we get to quarrying.

Most tools for stone-building can be purchased at hardware stores and building supply houses. Some, however, are rather specialized geological tools obtainable only at certain suppliers. To obtain such items as a geologist's hammer, hoe/pic, and gad-pry bar, contact the following suppliers:

Forestry Suppliers Inc.

US 800-647-5368

Canada 800-647-6450

www.forestry-suppliers.com

The Ben Meadows Company

1-800-241-6401

www.benmeadows.com

CHAPTER 2

Laying Out the Wall

Check Property Line

If the wall is to run along your property line, be sure that the whole thing is within your boundaries, unless your neighbor is eager to share in cost, construction and upkeep of a shared wall.

In the old days New England farmers would patrol shared stone fences each spring, each replacing the smaller winter-dislodged stones on his own side, the two of them joining forces on the big ones.

As the crochety Yankee farmer in Robert Frost's Building Wall puts it, "Good fences make good neighbors." Don't know as I agree with the sentiment. Frost didn't. I'd say, don't build a shared fence astride your property line unless you are already good neighbors and plan to remain so for the next several generations.

Plan It

First thing, lay out the outline of full length and width of the wall with cord looped to short sticks. For a curved wall you may want to lay out with thick rope or garden hose to describe a fair curve.

Clear the Way

If you can't avoid them, grub out any trees, stumps, or underbrush in the wall's area. Remember, that little maple sapling a few feet from the wall is going to grow. In time its roots will heave the rock, and the trunk may expand and push the wall aside. Cut it down.

May Need Footing

A low wall can be built right on the ground. In a few years the lowest stones will sink into the sod a bit and no one will know the difference. It is better stonemasonry, though, and makes for a sturdier wall, to dig out sod and topsoil so the footing — the lower courses or layers of rock — rests on the underlying subsoil or hardpan.

Most places where you find plenty of native rock the topsoil layer will be shallow, a foot or less deep, and removing it will be a minor chore, likely turning up an additional supply of rocks in the bargain. In some valley and lowland areas with deep, loamy topsoil a stone wall just set on the surface would gradually sink out of sight. But then, I don't think an honest stone wall would be comfortable in the flatlands.

Square It Up

Footing trench or no, the next step is to lay out your batter boards, stout stakes hammered in to mark the four end corners of the wall. Put the stakes in good and deep and use your mason's level to make them plumb — straight up in all dimensions. Make sure the tops of the stakes are several inches higher than the planned wall.

Cord Is Guide

Next, tie your cord to the four stakes at wall-top height and stretch the cord as tight as you can. Every six to ten feet, on both sides of the wall, hammer in more stakes. Make sure they are outside the wall area so string touches the inner-facing sides of each stake. You may tie or staple line to the stakes if building up or down grade or if the wind is bellying the upwind line on you. (A good many wall-builders, this writer included, have neglected to use the auxiliary stakes only to find that their supposedly straight wall ended up with a slight curve due to the prevailing wind blowing out the guidelines.)

Flat on Top

Now attach the line level to the cord and adjust till all four of the sides and both ends are level. This will define the approximate plane of the top of your wall. For most pleasing appearance, sturdiest construction and most satisfaction from the work, the wall top should be flat and level from side to side, either following the lay of the land in the long dimension or remaining horizontal, taking grade in graduated steps.

On a grade or flat, courses should be about the same thickness, each course running horizontally — parallel to the level. Sides of the wall should be vertical, or in higher walls they should have a slight inward slope (a slight batter) on each side. Ends and corners should be square and vertical.

Keep It Plumb

This isn't feasible 100 percent of the time with stone, but try to keep all dimensions as plumb and square as you can. You'll be looking at that wall probably for the rest of your life, and come fire, hail or high water it will be one thing standing for your great-grandkids to remember you by. Leave them the best job of work you can.

(Continues…)

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Excerpted from "Building Stone Walls"
by .
Copyright © 1978 Storey Publishing, LLC.
Excerpted by permission of Storey Publishing.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
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