Laying natural stone

Also perform the preparatory work carefully. If it is wet where the stones are to be laid you should dig deeper and place a drainage layer of macadam in the bottom under the base course. Otherwise the stones can move both vertically and horizontally in the winter when the ground frost comes. The chances of the stones returning to their original position when spring comes is very small.

You will need:

• Compactor/tamper
• Wheelbarrow
• Rubber or wooden mallet
• Spade
• Broom
• Rake
• Straight edge
• Screed rails
• Water level
• Folding rule
• Brick line
• Setting out pins

We recommend these materials:

• Base course, e.g. 0/32 or road gravel 0/16
• Rock flour e.g. 0/2
• Natural stones

Do this

1. Excavate the area where you intend to lay the natural stone. The depth you need to excavate depends on the height of the stone. Estimate about 5–10 cm below the stone height. Roughly adjust the surface.
2. Spread out the base course. The base course should be about 5 cm thick. Compact this course with a tamper.
3. Spread out a layer of rock flour, approximately 3–4 cm deep. Before you compact the rock flour, you should set out two so-called screed rails along the slope of the bed. The rails are laid from the bed's highest point to the lowest. You can use wooden battens 40x40 mm or iron pipe 32 mm in diameter. The length should be 2–3 meters. Press the rails into the material to the depth that gives the right height on the laid stones. Make sure the screed rails are horizontal with the correct incline. Use the brick line so that the screed rail's highest level is on the same level as the bottom of the stone.
4. Compact the rock flour using a compactor in the same way as for the base course. You can pack between the rails and fill with new rock flour until the substrate feels compact and hard. Now carefully sprinkle out a final layer of rock flour, about 1 cm deep over the whole bed.
5. Take the straight edge (aluminum is lighter to work with than wood) and set it perpendicular to the screed rails and remove surplus rock flour. The straight edge must be long enough to rest against the screed rails – at the same time as it reaches all the way out to the inner edges of the bed.
6. Prior to laying the first stone, you should carefully remove the screed rails and fill the gap with rock flour. Start by laying stones on the lowest level of the surface if making e.g. a path, driveway or a patio that slopes slightly from the house foundation. You work from the bottom up – even if the slope is only small. Lay the stones with an open joint of about 3 mm, all round. If you are uncertain you can place matches between the stones.
7. When you knock down the stones you should use a mallet preferably of wood or rubber.
8. When you have laid the complete surface, you must fix the stones using joint sand (rock flour 0/2). Spread a generous amount of joint sand and sweep down between the stones. Run over the complete surface with a compactor and once again fill generously with joint sand, which is swept down between the stones.
9. You may need to supplement with new joint sand after a few years to ensure the natural stone pattern does not move too much. You will see when this is necessary when hollows appear in the joints between your stones.