#Slab on grade ontario building code series#

The Wafflemat system has been recognized by several organizations for its environmental advantages, including the Breath California Award for Environmental Excellence.ДЄfter nearly 20 years of Research and Development, the initial and current design of the Wafflemat foundation system was installed in 1,100 homes in Northern California from 1993 to 1995. This contributes, and adds to, the environmental benefits delivered by the system.ДЇinally, as the Wafflemat foundation system does not require presoaking of the underlying building pad (often averaging over 8,500 gallons for a 1,500 sf footprint with other foundations types), significantly less water is used than with alternative slab-on-grade and/or deep foundations. In addition to the lowering of CO 2, the Wafflebox forms are made of recycled polypropylene plastic, and are a very 'green' material. Because a Wafflemat foundation system uses less raw materials (cement, steel, fuel, aggregate, and sand) than alternative slab-on-grade and/or deep foundations, it is also more environmentally sustainable. Since use of the on-grade Wafflemat foundation system typically results in a 20% - 30% reduction in concrete, a similar or even greater reduction in these other emissions will also occur.

The higher contact pressures along the base of the ribs and the voids, or low pressure areas in the system, limit deformations of soil due to moisture variation to the void spaces, reducing the impact of the soil's volume change on the on-grade mat slabs.Д®nvironmental engineers note reduced carbon and/or other air quality emissions are usually of the same magnitude as the reduction in concrete needed for any foundation project. An on-grade Wafflemat foundation provides all of the elements of the in-ground rib and uniform thickness slabs, but with greater performance provided by its geometry and smaller contact area with the soils.ДЄn engineer designing an on-grade slab makes the same calculations and follows the same requirements used in the design of traditional post-tensioned slabs on grade, and then applies them to the on-grade mat foundation ensuring the system possesses equal or greater stiffness. And, since the slab section is typically 12.5 to 16 inches above grade, it typically does not require a capillary break or moisture barrier.Д¬urrent design practice provides post-tensioned on-grade slabs with stiffness equal to or better than other post-tensioned slab types, but with less susceptibility to swell pressures exerted by expansive soils. It does not require presoaking underlying soil pads, and there is no need for footings, meaning no earth spoils.

The waffle slab is very stiff, with the cross section providing the needed strength to resist differential swelling resulting from landscaping practices, surface drainage, or flooding from any source. The completed slab then sits on the ground as a 'raft', with the void areas underneath the slab allowing for soil movement.

#Slab on grade ontario building code series#

The slab is created by placing a series of plastic forms ( 'Waffleboxes') that are either 8.5' or 12' in height, and 19' x 19' in plan, directly on grade to create a waffle-like grid of ribs, and then monolithically pour a post-tensioned reinforcedвЂ…concreteвЂ…slab over the Waffleboxes. The Wafflemat foundation system, also called a waffle slab foundation, is an above-ground mat foundation used to provide load-bearing capacity on expansive, rocky, compressible, or hydro collapsible soils.