Pressure treated lumber expansion vs fiber expansion.

ACI (American Concrete Institute) which are the industry standards in our trade say that expansion joints must be no longer than 20 feet a part in width. The maximum spacing for expansion joints is 20 feet and the maximum for control joints is 10 linear.  The purpose of expansion and control joints is to give the concrete a place to settle and/crack.  Concrete is guaranteed to do 3 things.  It gets hard, it settles, and it cracks so we place those joints to give the concrete a controlled place to settle and crack. 

You have two options for expansion joints.  The first option and our recommendation are to use pressure treated lumber.  The pressure treated lumber will last 5 to 6 times longer than fiber expansion.   Due to the northeast regions weather there will always be expansion and contraction of the concrete that cannot be avoided but We use 3 inch galvanized screws to lock the lumber into place.  The pressure treated lumber is a higher cost but untimely will save you money in the future from having to replace your driveway prematurely.   Papaneri recommends pressure treated lumber. 

The other option which we do not recommend but is the more commonly used due to it being the cheaper option is fiber expansion.  Fiber expansion is composed of fiber which is bonded together with asphalt.  The fiber expansion while it is flexible will break down over the next 2-3 years and I will eventually dissipate and disappear.  This will then allow water to penetrate between the slabs and then begins the undermining of your concrete.  This undermining is the process of water washing any sentiment which will cause voids underneath the concrete and eventually lead to cracking. 

Control Joints

Control joints are the intentional cutting of a concrete slab, and the purpose is to control the cracking.  Without control joints cracks are guaranteed to form, they will spread uncontrolled, and they will weaken the structure overall by allowing the water seepage which begins the undermining process.  Control joints are specific to every job and the thickness of the concrete poured.  Papaneri & Sons takes much time and effort to lay out all joint both expansion and control in the most aesthetically pleasing way. 

Get 10% off your first project!