DIY Stone Benches

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"The Complete Guide to Stonescaping," by David Reed, presents the basics of stonescaping in easy-to-understand terms for projects that will be functional and beautiful.
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The backrest stone of this freestanding bench was sunk into an earthen socket dug well below ground level.

Learn techniques for building functional and beautiful stoneworks that will last for ages with The Complete Guide to Stonescaping (Lark Crafts, 2013). With easy to follow instructions and hundreds of breathtaking photos David Reed shares stone projects to turn any yard or garden into a retreat. In the following excerpt, Reed offers a couple easy ways of constructing DIY stone benches. 

Imagine taking a welcome rest and enjoying your favorite vista while you sit on a bench you’ve built yourself. A well-built DIY stone bench, set in a favorite location, will see years of use and will require little or no maintenance.

Freestanding Benches

Freestanding benches — the simplest kind to build — may be located almost anywhere: under a tree, in the middle of a garden, on a woodland path, or next to a playground.

Although stone benches may not be as comfortable as garden furniture, when they’re set in the right location, they’re just as inviting. Choose a site to which you’ve always been drawn. A bench set in an area that you rarely visit won’t get the use it deserves.

The size of your bench stone (the stone you’ll sit on) will determine how difficult it is to set. Some of the benches shown in this section were built by a single person, but help from a friend always makes setting these heavy stones easier.

Selecting Stone

The hardest part in building a freestanding bench will be finding a slab 3 to 5 feet (.9 to 1.5 m) long and the supporting stones. If you’re not lucky enough to have an old piece of granite curbstone lying around, a trip to the stone yard may be in order. Don’t count on finding exactly what you’re looking for the first visit. Let people there know what you’re looking for, and they may be willing to keep an eye out for you. Bench stones don’t have to be rectangular in shape, but they should be heavy and at least 2 inches (5.1 cm) thick. Triangular, rounded, and squared slabs of stone will also work, although they’ll require three or four supports.

A bench stone should have a fairly even top surface, free of major protrusions that would be uncomfortable to sit on. If the bench stone’s underside is also even, it’ll make better contact with the top of the support stones. For narrow rectangular benches, each of the two supporting stones should be blocky with enough surface area on one of their ends to amply cover the width of the slab. When three or more stones support a bench, it’s less critical how much surface area comes into contact underneath the slab. Rounded stones with just a small point of contact work well when three or more support stones are used. The contact points of the stones will need to be of even height for the bench to sit level.

One way to support a bench stone is to place two substantial stones underneath it. As you calculate the required height of these two stones, keep three facts in mind. First, a comfortable height for the upper surface of a bench is 16 to 18 inches (41 to 46 cm). Second, you’ll set the two supporting stones about 4 to 6 inches (10 to 15 cm) deep in the soil — and even deeper if they’re especially narrow. Third, you must include the thickness of the bench stone as you estimate the overall height of the bench.

Let’s consider an example. You’ve decided that you want your bench to be 17 inches (43 cm) tall. Your bench stone is 4 inches thick, so you subtract 4 inches from 17 inches to get 13 inches (33 cm). Your supporting stones will be set 5 inches (13 cm) deep in the ground, so you add 5 inches to 13 inches. The height of each supporting stone should therefore be 18 inches (46 cm).

Look for supporting stones that are close to equal height. (You may compensate for minor differences by sinking the taller stone further into the ground.) The tops should be fairly flat and even, so they’ll make good contact with the bench stone, and the bottoms must sit securely in the soil.

When you’re ready to build the bench, start by measuring the length of the bench stone. Next, set the supporting stones so the bench stone will overlap them by 6 to 8 inches (15 to 20 cm) at each end. Make sure the tops of the supporting stones are level. Then set the bench stone. If this stone is heavier at one end than at the other, allowing the lighter end to overlap its supporting stone by a greater length makes the bench appear more balanced.

Another way to support a bench stone is to stack stones horizontally beneath it. If the ground is firm, dig a shallow, level spot for the first stone. In soft, loamy soil, excavate an area large enough to hold both the first stone and a 4-inch-thick (10 cm) bed of gravel underneath it. Tamp the gravel into the excavated area, set the first stone, and tamp more gravel around it. Check the stone for level; then continue dry-stacking stones to build the support. Two to three large stones look better in these kinds of supports than several smaller stones. Try to use large stones that fit together tightly. If you need to use smaller chinking or shim stones to steady the bench stone, place them in the least visible areas. A bench stone that rocks even slightly is very bothersome. Whether you’re working alone or have the help of a friend, take care to adjust this stone carefully on its supports. To find the best possible position, you may need to slide the bench stone back and forth across the supports until it’s stable.

Retaining Wall Benches

A bench may also be built right into a dry-stacked retaining wall. The portion of the wall that serves as the bench should be 16 to 18 inches (41 to 46 cm) in height. The simplest way to build a backrest for this kind of bench is to set large stones on edge, leaning them back against the soil bank at any angle that’s comfortable for you.

A backrest may also be dry-stacked as a part of the retaining wall. To do this, you must cut back into the soil bank in order to accommodate the backrest stones. You must also tie the backrest stones into the wall stones at the back corners of the bench and set capstones at its top. Whether you stack them as part of the wall or set them separately, backrest stones should rest on the back edges of the bench stones, about 18 inches (46 cm) from the front of the bench.

For more projects from The Complete Guide to Stonescaping: Read How to Build a Stone Culvert.

Reprinted with permission from The Complete Guide to Stonescaping: Dry-Stacking, Mortaring, Paving & Gardenscaping by David Reed and published by Lark Crafts, 2013.