Slate is a natural stone that is durable, slip resistant and beautiful for an outdoor living area such as a patio. Slate will blend in with its outdoor surroundings, giving a natural look to the patio, and will last for years to come. It is not the easiest material to work with, however, and you will need an extra hand or two for the project. There is a variety of slate stones and tiles you can use, and most are inconsistent in size and very heavy, but you can do it with some help.



Preparing Your Site

It's always advantageous to work out the design and size of your patio on paper first. Size the patio so that you won't have to cut many tiles to fit. Of course, even the best planning with slate may mean cutting tiles anyway as they can vary up to ½ inch each way. Another consideration in your planning is the location of the patio. If the patio will be against your house, it will need to slope away at an inch per 8 feet of surface. This will keep water from pooling around your foundation and possibly causing damage.



The area for the patio should be dug out to 7 or 8 inches deep, depending on the size tiles or stones you use. If the patio will be covered, a 4-inch bed of crushed gravel should be used on the bottom, followed by 3 to 4 inches of builder's sand. If the patio will be out in the weather, 5 to 6 inches of crushed gravel should be used for the best possible drainage. The top inches will be stone dust, which will be used in either case between the tiles once they are installed.





Installing the Gravel

Once you've dug the area out, shovel in the crushed gravel to the level you need. Rake it out to level as well as you can and then use a screed board to level it better. A screed board is a long 2 by 4 inch board that you pull over the top of the gravel to level it out. You can use a four-foot level on top of the board to check the level of the board. Once you have a flat area to work with, compact the gravel with a plate compactor or a hand tamper. A hand tamper will take a lot of time and muscle, and you can rent a vibrating plate compactor at the tool rental store for the day. The entire area should be gone over at least three times with the compactor. Next add your top coating, whether sand or stone dust and compact it into the gravel. The top layer should be sprayed down with a garden hose, more added and compacted again, as it will sift into the gravel as it's compacted.





Laying the Slate

In order to give yourself a nice straight start, use mason line and set it on stakes creating a square corner. Then start to lay the first tile there. Use a rubber mallet to tap the stone into the base layer. At this point you will want to use rubber spacers to keep a gap between the tiles. The common spacer for this type of tiles is ½ inch, but this is your design so it can be whatever you like. As you set the second stone in that row use a four-foot level to make sure the tiles are level with each other, and as the row gets longer set the level on the edge of a straight 2 by 4 inch board to keep your tiles level. As you start the second row, remember to subtract your slope if you are up against your house; otherwise keep it level. If you need to cut any tiles, use a circular saw with a diamond blade or a wet saw.



Once all of your tiles are in place, pull all your spacers out and dump stone dust on top of the tiles. Use a broom to sweep the dust into the gaps between the tiles. Wet it down with a garden hose and allow it to dry. This will compact the dust down into the gap and give you the room to repeat the step and add more. At this point the patio should be finished unless you decide to add a decorative border.