Build a Natural Stone Patio
To build with stone is as natural and human as life itself. Building with stone has been conducted worldwide throughout history in projects as variable as simple stone trail markers, fences, monumental European cathedrals, the Great Pyramids, and unique, mysterious structures such as Stonehenge. To wish to build a patio with natural stone is also natural. With some design considerations, planning, and careful selection of stones, you can do it.
Planning
Planning is essential to build any project well. Some decisions must be made initially. How large do you wish your stone patio to be? Where will it be located? Do you require a building permit?
In building with natural stone, careful selection of stones is important. For consideration of safety, stones with rounded, curved, or very rough, broken surfaces are not suitable for a patio. Stones that are excessively smooth may be slippery when wet.
Slates, sandstones, and other sedimentary rocks split on one plane, resulting in a relatively flat surface. Other types of rocks, such as granites, may be available commercially depending upon your geographical location.
For your patio, choose stones that are as flat as possible, at least an inch or two thick. If your intention is to build a frame around the patio, make sure you have chosen enough stones with relatively straight edges to fit up against the forms, or be prepared to cut them, or score and break the rock. Random shapes of natural stones provide the wonderful option of custom-fitting stones to the edges and trimming out the sod to match the rock, regardless of shape. A time-consuming process, the result can be astoundingly beautiful, maintenance-friendly, and natural.
To build a natural stone patio, you will need the following tools, materials and supplies:
Safety boots, gloves, and eye protection.
Shovel - a sharp, flat spade is a superior choice for this application
Garden rake
A pick -will be required if the soil is dry and hard.
A pointed (triangular) mason's trowel. A smaller one is easier to use.
Pickets
Rubber mallet
A carpenter's line.
A carpenter's 4' level
Natural rocks - the bigger and flatter the better, but handle carefully, they are heavy! Choose limestone, slates, sandstones, or other sedimentary rocks.
Sand (Clean construction sand containing no roots, dirt or rocks )
A rock saw or mason's saw. (For granites and hard rocks, use a diamond blade to cut and fit the stone if you are installing a patio frame )
A mason's hammer ( A hammer with a flattened pick on one end) to chip rocks
Framing materials (if desired) Framing may be dimensioned lumber such as 2x4's, framing timbers, or other selected commercial edging materials. If you wish to install a masonry edging, remember that in areas of severe frost penetration, you will require a steel reinforced concrete footing to prevent cracking and failure.
A screed. (Build one yourself as required)
Let's build the Patio!
1. Outline the approximate area with pickets and a line to visualize how the patio will look. Reorient it as necessary. Take your time, it's easier to change it now than later.
2. If you are installing framing, decide upon the measurements and establish the perimeter.
3. Excavate the site. Remove the grass or sod first, and donate it to someone that needs it, fill in holes, or build up other areas that need improvement.
4. Depending upon the average thickness of the natural stones selected, or to the depth of the framing chosen. Excavate sufficiently to allow a 3" layer of sand underneath the rocks when bedded in the sand. For instance, if your rocks are 2" thick, excavate the site to a depth of 5".
5. Install the framing level and square if applicable, and secure it to pickets driven into the earth on the outside of the frame. Ensure the top of the stakes are lower than the surrounding ground surface.
6. Install a fitted piece of dense ground fabric or black plastic to prevent emergence of weeds or tree sprouts.
7. Fill the excavation with sand to within 2" of the surface if your rock is 2" thick, or to within 1" if your rock is 1" thick. Level the sand roughly with a rake, and if using a frame and your selected natural stone is uniformly thick, build a screed and use it to level the sand perfectly. Notch out a 2x4 on both ends to allow the remaining "belly" to hang down to the depth required. Drag the screed across the sand, leveling it.
8. Pack the sand tightly, watering it to assist with the packing. Add sand as necessary and screed again. Repeat several times if necessary. The more the sand is packed, the less it will settle in the future.
9. Lay out stones selectively. For a random pattern, do vary the sizes and colours if applicable for the appearance you prefer. Allow a minimum of 1/4 or 3/8" between rocks. The space will be filled with compacted sand.
10. Bed the stones individually if they are different of different thickness, tapping them soundly into the sand with a rubber mallet. Ensure the tops of the stones are as even and as level as possible. Remove or add sand as necessary, ensuring the stone is stable.
11. To fit rocks along a frame, or to enable the stone to fit closer to an adjacent stone, score the top surface of the rock deeply with the rock saw and approximate the same mark on the bottom. Strike the rock on the underside cut line. The rock will snap on the cut, leaving a relatively straight edge. Fit and bed the stones as required. Don't forget to wear safety goggles as you chip off any sharp edges with the mason's hammer.
12. For a random, frame-free installation without edging or form, fit the stone slightly past the bedding sand, carving away the sod and soil as necessary using the trowel or shovel as required. Add bedding sand, pack it hard, and bed the stone. If it fits imperfectly, pack soil around the edge of the stone. Add grass seed or allow the grass to fill in any blank spots naturally.
13. If you are installing sandstone, or other soft stones such as limestone, consider sealing the surface with a sealer to prevent staining by grease and other spilled materials.
14. Fill all spaces between the stones with sand. Wash the sand in with water and compact it as much as possible. Wash additional sand in, or add sand as necessary if any stones are found to be unstable.
Now that you have a natural stone patio, maybe you would like to build a nice natural stone walkway, too, and you may even be tempted to build a little Stonehenge for a focal point. Your friends might just want you to hurry up and dig out the barbecue and hamburgers instead.