Should I use fibremesh or wire mesh reinforcement in a NB garage slab?

Wire mesh (welded wire reinforcement) is the better choice for garage slabs in New Brunswick. While fibremesh has its place in certain concrete applications, the freeze-thaw cycles, heavy vehicle loads, and potential for cracking in NB's climate make wire mesh the more reliable reinforcement for residential garage floors.

Wire mesh provides superior crack control where you need it most — at the bottom of the slab where tensile stresses develop. A typical 6x6-W1.4xW1.4 welded wire mesh (6-inch grid with 1.4mm wire) costs about $0.75-$1.25 per square foot and significantly improves the slab's ability to distribute loads and resist cracking from vehicle traffic, thermal movement, and minor foundation settlement. The mesh should be positioned in the lower third of the slab (about 1.5 inches up from the bottom in a 4-inch slab) and properly supported during the pour with chairs or dobies.

Fibremesh (synthetic or steel fiber reinforcement) mixed into the concrete provides some benefits — it reduces plastic shrinkage cracking during curing and can improve impact resistance — but it doesn't provide the same structural reinforcement as wire mesh. Fibers are distributed randomly throughout the concrete rather than positioned strategically where tensile forces are highest. In NB's climate, where garage slabs experience significant thermal cycling and potential frost action at edges, the structural reinforcement of wire mesh is more valuable than the crack reduction of fibremesh.

New Brunswick's frost conditions make proper slab reinforcement critical. Even with a proper foundation extending below frost depth, the slab edges can experience frost action if the perimeter insulation or drainage is inadequate. Wire mesh helps the slab act as a unit rather than developing isolated cracks that can worsen over time. This is particularly important for heated garages where the temperature differential between the warm slab and cold foundation creates additional thermal stress.

For vehicle loads, wire mesh is superior. Modern trucks and SUVs can weigh 6,000-8,000 pounds, and that weight is concentrated on four small tire contact patches. Wire mesh helps distribute these point loads across a larger area of the slab, reducing the risk of surface cracking or spalling. If you plan to store heavy equipment, trailers, or classic cars, wire mesh becomes even more important.

The installation process matters significantly. Wire mesh must be properly positioned and supported — many contractors simply lay it on the subgrade where it provides minimal benefit. The mesh should be lifted to the proper height with chairs before the concrete pour begins, and workers must be careful not to step it down during finishing. This requires experienced concrete crews who understand reinforcement placement.

Cost comparison favors wire mesh for most NB garage applications. Wire mesh adds $300-$600 to a typical two-car garage slab, while fibremesh adds $200-$400. The modest cost difference makes wire mesh the better value given its superior performance. Some contractors prefer fibremesh because it's easier to install (just mixed into the concrete), but easier isn't always better for long-term performance.

Consider combining both for premium applications. High-end garage slabs sometimes use both wire mesh for structural reinforcement and a small amount of fibremesh (typically 1-2 pounds per cubic yard) for additional crack control. This combination works well for heated garages, workshops with heavy equipment, or situations where the slab will receive a premium coating system.

Hire a professional for proper installation. Concrete reinforcement placement, proper concrete mix design for NB's climate, and finishing techniques all require experience. A properly reinforced and finished garage slab should last 30-50 years, while a poorly executed slab may develop problems within 5-10 years.

Need help finding a concrete contractor experienced with garage slab reinforcement? New Brunswick Garages can match you with professionals who understand proper reinforcement techniques for our Maritime climate.