In order to create a firm foundation for your stone patio, you generally have to start by digging. Sorry. Its almost inevitable. However, if you plan on creating a raised patio, you may only have to dig the base for the wall you'll use to raise it.
Before building your natural stone patio determine the best place for your patio. Many patios are ajacent to the house. This allows for easy transfer of food and supplies from the house to the patio during dinner parties. If you do choose to place the patio adjactent to your house, leave a few feet between the bulk of the patio and the side of the house. You can soften the edges of the patio and feather in the height difference between the house and patio using various plantings. Without plantings, this area could appear stark.
When determining your patio's position, consider various views: go inside your house. Look out your windows. How will your patio look from inside? How will your patio appear from various places in your yard, from yard entrances? Your inside and outside vistas should be rewarding to view.
What views will your flagstone patio offer? Are there gardens or features that you would like to enjoy while sitting on you patio? Will you add water features or planters that can be enjoyed from the patio? Place your patio accordingly. Spray the outline of your patio on the ground. Draw another line 4" outside your patio outline.
If you are going to create a patio more than one hundred square feet, you won't want to do this on your own. All soil gets heavy after a while. Clay, is horrendous. Sometimes, it is easiest to till the soil before you remove it. Remember, if you have to move the soil a significant distance, or need to dispose of it, you will need to load it into a wheelbarrow. Don't overfill that barrow or you will tip it and have to reload it.
So, Time to Start Digging. Dig along the outside line using a flat shovel, working from the area furthest from the soil's final destination. You don't want to traverse areas you already dug out. The wheels of you wheelbarrow will bog down in any loose soil and getting it out of the hole you've dug out will not be easy.
Keep in mind, you have to put that soil somewhere. If you have any low spots on your property, consider using the top soil to fill these. Usually, the topsoil is only three or four inches deep. Anything below that level is usually useful only for creating raised areas, mix this soil with compost for planting, or filling areas in which you will never plant.
At my own home, I mixed the soil from the hole with compost to create a mounded garden bed. This is preferable to removing the soil from the sight, if at all possible.
Finding a company that is willing to haul away fill soil, any soil not immediately useful for planting, can be a challenge because they need a place to dispose of the soil. Disposal sites are limited. If you must remove the soil from the site, look on craigslist. I have found many people looking for free fill soil. You just have to get it to their site.
Digging your patio or walkway base to the right depth and width is essential. Determine the range of thickness of your flagstone. Most natural flagstone comes in thickness between one (1) inch and three (3) inches. Generally, it will be sold in range between 1-1 1/2" or 2-3", with a wider actual range to be expected. It is always easier to handle thinner pieces because they are lighter weight. However, keep in mind, thicker pieces are less likely to break if dropped. In addition, the joints will set more firmly with thicker stone. Thin flagstone is best used in mortared applications. Most 2-3" thick flagstone covers between 60-90 square feet depending on the thickness
Add the greatest thickness of the flagstone (i.e. for 1-2" stone, you will use 2") to the depth of the road gravel or crushed concrete base, generally 4-6" deep and the depth of the bed of "chips n dust" or stone dust in which you will lay the stone (1-2"). Plan on digging approximately 8-10" deep. Better to do the extra work now than to watch your hard earned patio collapse a few years down the road because the base was not deep enough.
I generally dig an area 4" wider on all sides than the finished patio will be. This allows the crushed stone base to support the edges of the patio sufficiently. Remember to slope the subsoil away from any buildings. You don't want water collecting against the foundation of your house. Make sure to eliminate any low spots that could fill up with water during winter and cause frost heave. Use a landscape rake to level/smooth the foundation soil.
Yes, this much digging can be difficult. Especially if you are digging by hand or have to move the soil a significant distance in a wheel barrow. The soil removed from a 100 square foot patio will be 2.5 yards or 3.5 tons, minimum. You will be bringing in just as much material. Don't let this discourage you. Take your time. Bring in help if needed. The end result can be well worth the effort.
Once the soil has been removed to its new location, start bringing in the gravel or crushed concrete. I prefer to use crushed concrete. It is recycled material and compacts better than road gravel which has rounded stone. Place 2-3" inches of crushed concrete evenly across the patio area. Hose down the crushed concrete with a nozzle set on "shower". Too much or too little water and the base will not compact properly. You can tell when the base material is properly watered by taking a handful and creating a ball. No water should drain out and the ball should hold together fairly well.
Next, compact the first layer of crushed concrete. It is best to use a plate compactor. Tamping by hand can be exhausting and leave your arms and shoulders hurting for days after. In addition, most people can not muster enough strength to compact the stone sufficiently. You may still need to use a tamper in areas the plate compactor cannot go: corners and tight curves. You can rent a compactor for four hours at most tool rental places including Home Depot. Run the plate compactor over the entire area, starting along the outside and working your way in. Repeat this 2-3 times.
Lay down the second layer of crushed concrete and repeat the compaction process as mentioned above. Make sure to eliminate any dips in the stone base. To fill dips, use a shovel to add crushed concrete. Raking with the tooth side of a garden landscape rake will sift the stone and separate the larger and smaller particles. Avoid this. Once all the dips are filled, run the compactor over the patio base two more times.
Install aluminum edging along the outside of the patio area, remembering to move the edging in 3-4 inches to allow for proper support of the flagstone.
Finally, spread two inches of chips n dust or stone dust. Compact this layer as well. As you lay down individual pieces of flagstone, you will need to remove or add to this top layer according to the thickness of the pieces.
Coming soon: How to Install Flagstone.
Good luck.
Pictures will be added soon.
If you have any questions, or would like assistance in designing or installing your patio and live in the Grand Rapids, MI area, feel free to email me at
omegabrickandlandscaping@hotmail.com or call Brent at (616) 328-3258.
