Dry stone walls are built as retaining walls on slopes and terraces, as edging for raised beds or freestanding for subdivision or demarcation of the garden. The term “drywall” already reveals a lot about the construction: The stones are lying “dry” on each other, because the joints are not filled with mortar. This has the advantage that the joints can be planted and many useful insects such as wild bees and bumblebees can hide in the small wall niches. Even lizards and blindworms like to choose the warm, dry wall cracks as a place to stay.
This is how you go about building a drywall
First, dig out the foundation trench: width = one third of the planned wall height, depth = 40 centimeters (15 inches). Compact the ground and fill the trench 30 centimeters (12 inches) with a mixture of gravel or mineral (grit 0-32 mm (0-1.25 inches). Compact the foundation carefully and apply a 5 to 10 centimeters (2 to 4 inches) layer of construction sand. Rake the surface smooth and slant it off to the slope. Now you can lay the first row of stones. Select the largest stones because they play the “supporting” role for the wall. Lower the stones a few inches deep in the foundation and keep it about 40 centimeters (15 inches) away from the slope to save space for the backfill.
Tip: You can easily build a curving wall by eye. However, if you want a wall that is straight, you should stretch a string parallel to the slope so you can orientate yourself.
Dry stone walls can easily be created up to a meter high (about 3 feet). However, if they are larger or are directly on the road, you should consult a specialist. Nearly all types of stone are suitable as material for the drywall: collected fieldstones or already processed stones from the builder’s merchant. Natural stones made of granite, sandstone, gneiss, jurassic or limestone are particularly attractive. These are only rough or not cut and thus have an irregular size and shape. Such stones give a wall a rustic and natural character.
If there is a quarry in your area, you can generally get stones from there for a cheaper price. In addition, the usually quite high transport costs remain within the scope. You save energy and time by unloading the stones directly at your own building site and sorting them by size. For this purpose organize a few strong helpers. Together, heavy stones can be lifted much easier.
When planning and preliminary work is done, you can start building the drywall. Which type of construction or type of wall you choose depends on what you trust yourself to do. If you have no previous experience, you should create a simple layered masonry.
On the other hand, the material that is at your disposal also plays a role. Whether the stones are natural, cut or broken – in general, dry stone walls have a natural appearance. The stones do not have to be set correct to a millimeter. Just make sure that the transverse joints are approximately horizontal.
If you have a very humid ground or you want the wall to be very high, you can install a drainage pipe (DN 100 = 10 centimeters (4 inches) in diameter). Lay the pipe with a slight slope behind the lower stone layer, so that the water is led away to one side. Fill the joints with loamy sand before starting the second row of stones. In larger wall joints, you can also fit so-called “pendentives” (= small stones). Immediately plant the gaps during the construction of the wall before you place the next stone row. If the plants are set later, the roots can easily be damaged.
Then lay the stones in a staggered manner without creating any cross joints. Use a large hammer with a rubber attachment to beat the stones, so that the stones no longer wobble and the sand in the joints becomes denser.
Step by step to the drywall
Pay attention to a slight slope (10-15%) towards the slope, so the wall can not tip over. Backfill the space between the wall and slope with sand or gravel after each layer of stone and compact it slightly. This stabilizes the wall. In each row, place about every fifth to tenth stone across the wall, so that it protrudes a little deeper into the slope. These anchor stones ensure that the wall is interlocked with the slope. The most beautiful stones should be reserved for the wall cope, because they are visible from the front and from above. For a perfect finish, use flatter, even stones, which may also be suitable as seating. The backfill is covered with 15 to 20 centimeters (6 to 8 inches) of topsoil and planted so that shrubs and herbs can grow beyond the top of the wall.
Overview – construction of the drywall
- Start with the foundation. To do this, lift a trench about 40 centimeters (15 inches) deep at the desired location, compact the bottom with a rammer and fill it with gravel.
- This is leveled and therefore compacted, so that about 5 centimeters (2 inches) below the soil surface, a flat gravel bed is created. It should be one-third as wide as the wall should be.
- A drainage pipe at the back of the foundation absorbs excess leachate.
- For the first layer, choose large stones with a broad support surface and place them in the ballast bed with the front sides inclined 10-15 percent backwards from the vertical (10-15 centimeters per 100 centimeter wall height (4-6 inches per 40 inches wall height)). This so-called metering is important to keep the wall safe. Tip: Build wooden slats into an angle template to check the incline quickly. You should also stretch a horizontal string to straighten the stones.
- When the first layer is covered, backfill with a mixture of gravel and earth, which is then slightly compacted. Lay it layer by layer and level out the contact surfaces with loamy topsoil. If necessary, flat stone wedges (“pendentives”) are used so that all stones rest stably. The depth of the stones should vary from one layer to the next and also within the layers to interlock the masonry with the backfill. Avoid continuous vertical joints (“cross joints”), they affect the stability of the wall.
- In the larger columns, you can plant shrubs while laying up.
- The last stone layer is called cover layer. It should consist of even, flat stones. The back is filled with topsoil and planted.
When building your drywall, pay attention to the correct joint: staggered joints can effectively absorb the earth pressure that arises, for example, behind a retaining wall. With cross joints, however, weak points are created. They do not stand up to heavy loads!
In regular layer masonry, all the stones in a row are of equal height. Suitable materials are processed ashlars made of sandstone or granite. A very interesting joint pattern has the irregular layer masonry. With different height, rectangular and cuboid stones variety is put into play.
Quarry stone masonry consists of unprocessed natural stones of all sizes. They are set so that as many as possible continuous transverse joints are available. The rustic cyclopean masonry consists of rounded stones, which are stratified with the flattest side to the front. The joints can be planted well.
Plant dry stone walls
And last but not least, its ecological value speaks in favor of a drywall in the garden: in spring, it is a welcome hot spot for bees when planted with shrubs or herbs. Beautiful shrubs are for example the mountain sandwort, a winter hardy frost flower or the Mount Atlas daisy. However, there are also practical plants, such as various types of thyme, which still provide added value for the kitchen. Of course, if you want to let nature run its course, you can. Over time, plants will settle in the joints on their own. In addition, the warm stone joints provide numerous insects and reptiles an important habitat.
Recommended plants for the drywall
- Purple saxifrage (Saxifraga oppositifolia) grows 3 to 5 centimeters high (1 to 2 inches), prefers humusous lime debris and shows its large flowers from March to April. In Switzerland, the perennial can be found up to 505 meters (1.600 feet) – the highest European flowering plant
- Maidenhair spleenwort (Asplenium trichomanes), also called stone feather, is one of the few ferns that have adapted to the barren life in stone joints. It is barely 20 centimeters (8 inches) high and prefers shady, damp wall cracks. After growing, however, it is amazingly dryness and sun tolerated
- Ivy-leaved toadflax (Cymbalaria muralis) prefers calcareous, humus rich gravel soils in the sun and partial shade and seed itself well. The only 10 centimeters (4 inches) high shrub blossoms very long – from June to September
- The Kamchatka stonecrop (Sedum kamtschaticum) is a very drought tolerant, up to 15 centimeters (6 inches) high herbaceous perennial for sunny to partially shaded places in the stone garden. It blooms from July to August
- The rock-soapwort (Saponaria ocymoides) shows its lush flower dress from May to July. The vigorous, lime-loving shrub is 15 centimeters (6 inches) high and likes pervious gravel soils in full sun
More plants for the drywall
- alpine cinquefoil (Potentilla verna)
- mouse-ear Hawkweed (Hieracium pilosella)
- tasteless stonecrop (Sedum sexangulare or S. acre)
- Cypress spurge (Euphorbia cyparissias)
- thrift (Armeria maritima elongata)
- stemless carline thistle (Carlina acaulis)
- viper’s bugloss (Echium vulgare)
- spiked speedwell (Veronica spicata)
Leave the green to itself
Of course, it can also be left to nature to green the wall. Not only lichens and mosses conquer the stones over time. Aaron’s beard, creeping Jenny and wall-rue also set themselves up and let the building merge with its surroundings. In addition, other plants, which are at home on gravel and grit, conquer the dry cranny places: viper’s bugloss, campion or Carthusian pink prefer nitrogen-poor locations. At the foot of the wall, it is a pleasure to enjoy columbines, mulleins or evening primroses.
To ensure that tiny and sun-hungry plants remain permanent guests on the drywall, regularly remove wheatgrasses and grasses. If you cut off spent blooms and dry stems, the plants regain new strength and reduce the shadow cast. At the latest in spring, cut all plants down to a few centimeters (inches).
Other plants for the drywall
sea thrift (Armeria maritima)
red valerian (Centranthus ruber)
cheddar pink (Dianthus gratianopolitanus)
whitlow-grasses (Draba aizoides)
Dalmatian Cranesbill (Geranium dalmaticum)
alpine gypsophila[ (Gypsophila repens)
goldmoss stonecrop (Sedum acre)
rock-cress (Arabis procurrens)
rock fumewort (Pseudofumaria lutea)
yellow fumewort (Corydalis flavula)
Wild strawberry (Fragaria vesca)
herb-Robert (Geranium robertianum)
Moss saxifrage (Saxifraga arendsii hybrids)
In the first year of the plant masonry should be watered in joints and above the top of the wall. Later, this is no longer necessary if the species selection has been considered site-specific. In spring, you can cut dried plant parts, if necessary. Every now and then, the steadfastness of a wall should be controlled.