The addition of a slate patio in the landscape can enhance the look of any property, add value, and provide a social focal point or a private hide-a-way. Adding an outdoor room can only be viewed as a benefit to the homeowner.
Product selection is almost unlimited and readily available and is either manufactured (pavers) or naturally occurring (slate, flagstone).
Once a site for your patio has been chosen, thought must be given to infrastructure before you begin excavation. Will there be immediate or future needs for: irrigation, electrical, gas or drainage. Even if you do not think there is, it would be wise to bury a 3" pipe for future access.
There are a few ways to install your slate patio.
- On existing lawn (not recommended)
- On a sand base
- On a mortar bed
This discussion will deal with points two and three.
Measure the area to determine approximate square footage. Square footage will dictate the amount of material required to build your patio. As a general rule one ton of 1.5" slate will cover about 100sq. ft. 100sq. ft. will require 1 cubic yard of 3/4" road base for a 3" depth and about 1/3 of a cubic yard of coarse sand at a 1" depth. Why do you need to know this? The reason is we have to know how deep to excavate our area. Our example of 100 sq. ft. should be excavated to a depth of 6"
Road base must be compacted (to prevent settling) either with a gas powered plate tamper or a hand tamper. It is not essential to get this course absolutely level as the sand or mortar will compensate for deviations in either the slate or the road base. The sand does not need to be tamped.
Your patio should have a 1% to 2% slope away from existing structures to allow for drainage. This is equal to 1"-2" of drop for 10ft of length of the patio. If you are using mortar instead of sand, your mix should be three parts sand to one part portland cement. The placement of your patio stones should equal the surrounding grade.
It may be necessary to install a perimeter edge to your patio. Some edging types would be: hard plastic L shape, pressure treated lumber, manufactured stone or blasted rock.
If you are using sand to lay your stones on, you will have to fill in your seams. This is similar to 'grouting' tile. You can use a 3:1 mix of fine sand and portland cement. Color additives are available to color concrete mix if desired. Spaces may also be left in some areas to plant low growing perennials such as thyme to soften the overall look.
Let all your cement 'cure' for about two days before you use your new patio. The time and effort you put into this project will pay years of dividends and enjoyment.
Products to get the job done:
3/4"-1" Pennsylvania Bluestone, Mountain Walnut 2", 1.25" Midnight Tumbled Slate, 1 1/2" Ocean Pearl Flagstone, Canyon Bluff 1.5"-2" Slate, 1" Gold Leaf, Park Valley Green Flagstone 3/4"-1", 3/4"-1" Silver Strike, 1.5"-2" Tumbled Mica River Grey, 2" Gold Leaf, 2" Random Tumbled Bluestone, 2-3" Silver Falls, Screenings, Jelly Bean Pebbles, Medium Load Delivery