When building a paver patio, it is important to consider the drainage of your backyard. One such important topic to consider when creating your plan is that of the slope for a paver patio. There is a range that needs to be considered and may be affected depending on the type of project you are building and the type of product that you are installing.
Slope for a Paver Patio
Slopes for paver project are fairly specific to patios, as other paver projects can be manipulated slightly depending on the grades surrounding them. For example, a paver driveway already has the slope built into it. This slope is the top of the garage floor to the top of the sidewalk or road. There is no way to build in a step into the driveway to reduce the slope in any way. A walkway can also have a more aggressive slope than a patio if you are trying to reach a specific grade and it does not quite make sense to add in a step to reach that grade. For example, if you have two inches you need to make up you likely would not want to add in a two inch step rather you would improve that slope on the walkway over a greater distance in order to make up that two inches.
A paver patio should always slope away from the house. The amount to which you would want to slope that patio depends entirely on the type of project that you are building in your backyard and the type of product that you are using.
The recommended slope for a paver patio ranges from 1/8 inch to 1/4 inch per foot or a 1 percent to 2 percent slope. This ensures that water landing on the patio will runoff with minimal resistance while also ensuring that you can place a table and chairs on the patio safely. Choosing what slope you may choose has a few factors to consider.
On a side note if you are interested in calculating the percentage of your slope, this is how you would calculate that. You would take the amount in inches divided by 12 inches which is converted from one foot. For example, 1/8 inch per foot slope would be 1/8 divided by 12 or 0.125 (1 divided by 8 to create a decimal value rather than a fraction of an inch) divided by 12 equals 0.01 converted to 1% when multiplied by 100 to create that percentage.
Minimum Slope for Paver Patio
The minimum slope for a paver patio is a 1/8 inch per foot slope or a 1 percent slope. This is enough for smooth surface pavers or slabs to allow the runoff of water from the patio surface. If you are using a smooth paver or slab for your patio, then it is likely that water runoff from the patio will meet little resistance and you can opt for a less aggressive slope to allow for that water runoff. Additionally, if you combine a semi-permeable or permeable jointing compound this water will have less buildup on the surface of the pavement. When combined with a space that gets a lot of sun throughout the day, the chance for water buildup on the surface is minimal and you will be able to opt for a less aggressive slope at 1/8 inch per foot slope.
Maximum Slope for Paver Patio
The maximum slope is 1/4 inch per foot or a 2 percent slope for your paver patio. This is actually the recommended slope by ICPI or the Interlocking Concrete Pavement Institute. If you are using a textured paver or slab for your patio, it may be beneficial to opt for the maximum slope for your patio to ensure water runoff. Especially if you are opting for a polymeric sand or a less permeable jointing compound where water only has one exit off the surface which is following the slope you will want to opt for the maximum slope. Additionally, if your patio is in an area that does not get a lot of sun or there is more water runoff from surrounding structures onto the surface, you may want to increase that slope to ensure the water does runoff the surface of your patio with minimal resistance.
If water does stand on your patio for a significant time, you may get a buildup of mold and mildew over time and will need to clean the surface consistently to maintain the surface of your patio. This may also lead to the degrading of your jointing compound material which will cause you to need to replace it more frequently over time as well.
Building a Patio on a Slope
Now that you know the slope range for your paver patio, you will need to plan your project accordingly. This planning requires you to choose where the top of your patio will be along your foundation which will then allow you to plan the number of steps you need to build up to your entrance / door. You can then plan the slope you chose away from the foundation. With that applied slope you will know whether you will need to build up the end of your patio slightly with some soil to meet the top of pavement if the patio will be higher than the existing grade or if you will need to build a raised patio if this measurement is significantly greater where you will not be able to build up your yard to meet the top of pavement. It is also a possibility that your planned patio height lands below the existing grade. In this case you would build a retaining wall to allow you to lower your existing grade and build your patio on your proposed height.
Alternatively you can raise or lower the height of your patio along the foundation to reduce or increase the number of steps going into your house and to ensure that you do not need to build a raised patio, or build up the yard, or build a retaining wall along the back of the patio.
Learn how to use string lines to set your slope when planning and laying your paver project.