Levelling Your Patio
Building a new patio or rehabbing an old one can be costly and backbreaking. As long as you are going through the effort of doing it, you should make sure it is done right. A successful patio job begins with making sure the base is built with appropriate fill dirt material and sand. If you are repairing a patio, chances are the problem is the result of a poorly prepared base.
Once your patio base is solid and level, completing the job will be easier. A professional dirt contractor can make sure you use the right materials for your project and instruct you on how to level a patio, so you are more likely to be thrilled with the finished result for many years.
How to Level a Patio
1. Call Miss Utility and obtain any necessary permits.
Before starting any work, make sure you have any underground structures marked and obtain necessary permits from the local authorities.
2. Correct any slope with fill dirt.
If you are building on an area of your yard that slopes, or repairing a patio that settled poorly, you will need to first correct the slope. Depending on the severity of the slope, you may need a professional with heavy equipment who knows how to level a patio to do the job correctly.
To correct a slope, you will need to bring in fill dirt to fill in and build up low areas. Correcting a steep slope requires more fill dirt than a milder slope. Clean fill dirt, that is, dirt that is free of organic material, concrete chunks, and miscellaneous debris, is not terribly expensive. It will enable you to fill areas of erosion and stabilize the ground. The labor and heavy equipment needed to correct the slope will add more to the total cost than the cost of the dirt. Areas with deeper and large gradients require more resloping to create a flat area. As a rule of thumb, a hill with a gradient of 14% would likely cost twice as much to level as one with 7%. If the area is subject to significant erosion, it may require more grading to keep the soil in place. Each regrade can add cost to the original price.
3. Mark the patio site with string and boards.
For a new patio, outline the patio site using stakes and string for a square or rectangle shape, making sure the corners are square. If the patio is rounded in shape, use string or a garden hose to outline it.
To repair a failing patio, mark the low or cracked areas where portions will be removed.
4. Dig out the site.
Following your outlines, remove any sod or existing pavement and soil down to the proper depth. The proper depth will be the amount of finish surface, less paver thickness, setting bed depth, and base material. The amount of base material you need should be determined by a soil engineer. Base thickness normally ranges from 6-inches to 12-inches. Dig out about six inches beyond your outlines to give you room to install edgings. If your patio is large, you can rent a sod-cutter to make the digging a little easier. As you dig, try to preserve a slope that drops about one inch for every four feet. The slope should angle away from your house or other nearby structure to help proper water drainage. You can fasten a one inch block of wood to your level to help preserve the right amount of slope.
If you do not know how to level a patio and are repairing it, you may be able to simply remove the problem areas and leave the rest of it intact.
5. Compact the subgrade, install base fill, and compact base fill.
For a new patio installation, use a compactor appropriate for your soil to compact the grade. Lay landscape fabric over it to deter weed growth. Fill the excavated area with the amount of fill as determined by your soil engineer in stages of no more than four inches of fill at a time, being sure to preserve the slope. The fill used as the base should be an angular granular material that will compact well. Good fills are gravel or crushed stone. These are high-strength and permeable materials with low compressibility, which is ideal.
Proper compacting is necessary. Wet it and then compact it with a plate compactor.
If you are just replacing base material in isolated areas, you may have to remove a larger area of the patio surface to enable you to compact the base fill well.
Whether you are using pavers, concrete, natural stone, or wood for your patio, it needs a good foundation to support it over time. A well-prepared subgrade will ensure a successful result. It avoids unexpected settling and water accumulation leading to a weakening of the base. Even when you use good fill material, poor compaction will cause cracking and sinking of your patio, leading to expensive repairs.
6. Install edging (for paver patio).
Installing edging for paver patio will help keep the pavers in place by providing lateral resistance to the paver load.
7. Install paver bed sand.
Lay two lengths of one-inch PVC across the patio bed. Install one to two inches of concrete sand, coarse washed concrete sand, or granite stone dust, using the PVC as a guide for the amount of sand. Level the sand by pulling a straight 2 x 4 along the length of the PVC, a process called screeding. If you have maintained a slope and uniformity in your base, the sand will lay the same way.
8. Install pavers and joint sand.
Lay the pavers on the leveled sand bed, leaving about ¼” space in between each one. Keep the surfaces even by adding sand underneath or tamping down high spots. Spread paver sand into the joints using a broom and hand tamper. Repeat until the joints are filled. Use a leaf blower to remove sand from the surface of the stones. Spray with water and let cure for 24 hours.
Contact a Dirt Contractor for Fill Needs
If you do not know how to level a patio, contact a professional dirt supplier before you star your project for advice on the best fill materials, sand, and stone to use in your area for your particular project. Depending on the size of your project, the dirt contractor may visit your project site to help you determine the quantities of dirt that you need and whether special equipment may be necessary to access the site.