Concrete Facts

BASE	Well compacted, and uniformly graded base. This insures the concrete thickness will be consistent. Thick and Thin areas will create weak points where a crack will develop.
FORMS	Wood or steel forms are used to define the edges of the work and to control the grade and slope of the surface so that water will drain properly.
WIRE MESH	Not always necessary, but it is inexpensive insurance to add strength to the concrete and to hold it together where it would crack (under control joints). 6 x 6 x 10 gauge or heavier is recommended.
REBAR	Used more for self-supporting structural slabs (eg. Porch top with fruit celler underneath).
CONCRETE	32 Mpa. (4600 psi) strength with 6 - 8% air entraining and a 3" to 4" slump. Manitoulin hard stone eliminates surface "popping" of concrete (soft stone holds moisture, freezes, expands and breaks).
THICKNESS	Minimum 4" for sidewalks and patios, 5" for driveways, 6" or more for heavy trucks.
EXPANSION JOINT	1/2" thick fibre expansion joint filler is placed along foundation walls, pillars, curbs, etc., where a new concrete slab is poured. This allows the concrete to expand and move.
CONTROL JOINT	Sawcut or tooled joint in concrete that should be at least 1/4 the depth of the concrete. This "tells" the concrete where to crack. If no control joints are put in, the concrete will crack randomly due to frost or stress.
CURING COMPOUND	Acrylic sealer may be applied to freshly finished concrete to prevent it from drying out too quickly (which causes surface cracking and fissures). In hot weather it must be used. Concrete cures slowly, reaching full strength in 28 days.
FINISHING	Non-slip broom finish is recommended for sidewalks, driveways or other foot traffic areas. A smooth steel trowel may be desired for a garage floor (to make cleaning easier).