the job of the week brings us to   historic Philadelphia and the use of cobblestone for a driveway boarder. Cobblestone make great use of their strength when used in high traffic areas. Cobblestone are granite and come in a many shapes and sizes. In the Philadelphia area where they are abundant many are historic stone that our fore fathers walked on.

This particular job we used a yellowish cobblestone with a grey speckle look. The cobblestonerange slightly in size 9×5 and 10×5. When using cobblestone for your boarders try and get the same thickness in the cobblestone. They will line up alot better and look more professional.

This job we started out by removing 10″ down of earth7″ wide  and tamping the soil down as tight as possible. If you have a gas powered tamper than use it or if you can rent one I suggest you do. If that’s not possible then you must use a hand tamper and slam the tamper straight down onto the earth. Once you have the earth tamped then add your concrete base. Add at least 4″ of 3500psi concreteto your trench and let sit. Make sure when your pouring your concrete base that your pouring the concrete level. You can drive a stake at one end of the boarder and one stake at the other end. String a line up one end and put a line level on the string and that will tell you if your string is level.

  Hint: You have to make sure the string is pulled tight or you won’t get an good reading on the level. The string height must be the height of your concrete. Now you can pour your concrete nice and level. Let the concrete harden over night and in the morning your ready to set your cobblestone.

You’ll need three parts concrete sand and concrete sand only to set your cobblestone. Use one part type I cement and three parts concrete sand. Mix dry first and then wet. Make sure not to add too much water it will ruin our setting bed. I even like to add a slurry coat of cement and water mixed to a pastie texture. I will dip the bottom of my cobblestone into the slurry right before I’m going to set the cobblestone. Once set in the wet bed of sand and cementand the bottom slurried. Your cobblestone are set so well that it can withstand the occasional car bumping into them. If the job calls for it, we will point the joints between each cobblestone. Sometimes I’ll point the stone flush or do a concave design. Either way it helps to hold each stone. If I need for water to flow through the stone then we will lay them as tight as possible to one another.

Cobblestone boarders are great around landscaping areas. Cobblestone can be used flush with other materails or be raised above surrounding materials such as flower beds or patio’s.

 The only time I won’t use a cobblestone is when clients ask about building a wall out of cobblestone. I find that cobblestone are not great stacking stone and don’t bond as well as I would like when stacked. I’ve seen mortar joints fail sooner than they should be when people use them to build walls.

If you use the cobblestone for a area that has to absorb water then set the cobblestone in a dry manner. See the page How to set a patio it will give you different bases you can use. Hope this helps Johnny Mason