Do Concrete Slabs Really Need Welded Wire Mesh?

Over the past decade, many production builders have turned to synthetic fiber mesh to reinforce concrete slabs to help reduce surface cracking. In the process, many builders have completely eliminated traditional welded wire mesh (WWM).

However, while fiber mesh has advantages, it also has potentially costly disadvantages.

This may sound surprising, because the great appeal of fiber mesh is the time and money it can save. By using it, builders don't have to pay extra for concrete mesh and concrete contractors don't have to take the time to install it properly; in fact, some concrete contractors offer price breaks for fiber mesh.

 

 

Unsightly Cracking Problems in Concrete Slabs

While fiber does reduce surface cracking, it will not eliminate it completely. Worse yet, the lack of WWM can be a real weakness when cracks appear.

This is because a properly installed WWM will prevent further separation of the concrete on either side of the crack and keep them in the same plane, i.e., prevent differential settlement. Fiber mesh will not.

Repairs to differential settlement will not leave the greatest impression on the purchaser. You will have to grind the surface on both sides of the crack, fill the gap with epoxy and try to flatten it all out. Even if done properly, this will leave visible scars.

While most of these scars are decorative, they will scream "poor workmanship" to customers, or at least cause many to question the structural integrity of the home's panels. Of course, the builder must pay for the repairs.

We are seeing more and more of these problems on job sites as the use of fiber mesh increases... but we are also seeing more and more builders taking notice. Shortly after switching to fiber mesh, one of our customers found a dozen cracked and settling slabs at any given time. They reintroduced WWM and the problem almost disappeared.