FAQ

concrete

• Are there any other benefits to placing gravel beneath a concrete slab?
  Yes. It will prevent the concrete from being exposed to the natural sulfates in the soil. These sulfates may cause "Sulfate Attack" which forms distinct cracks in the slab and or the foundation.
• Are there curing benefits to placing concrete on a gravel subbase?
  Yes. Gravel will not absorb moisture at the base of the slab, therefore, the slab will retain an adequate amount of moisture for optimal curing. This benefit will also reduce the incidence of shrinkage cracks caused by rapid moisture loss.

drainage

• Why do we place gravel beneath slabs and in basements?
  Gravel ensures adequate water drainage and it is a material that most easily achieves compaction.
• Why do I need drainage beneath a slab?
  Drainage beneath a slab reduces the incidence/magnitude of concrete slab curling. Curling occurs when there is more moisture at the base of a slab than there is at the top of the slab. This causes the top of the slab to shrink and curl in towards the center. Drainage also prevents shrink/well of the subbase which may generate stress fractures in the slab.
• Why do I need drainage around a foundation?
  It reduces hydrostatic pressure against the walls of a foundation. Water retained in the soils around a foundation cause the soil to swell and exert horizontal pressure against the foundation. Drainage around the foundation will also reduce the incidence/magnitude of water seepage into the basement or crawlspace of a home.