For manual excavation use shovels and spades. For large volumes of excavation in Toronto, it is reasonable to use a machine (which in most cases is possible), which is more cost effective.
If the pit is dug manually, a wheelbarrow must be used to remove the soil. When several people work, you should stand on both sides of the car so as not to interfere with each other. If the object under construction has a basement, you must first remove the turf and soil layer. If there is no basement humus should still be removed, because after rotting plants and roots settle the ground and lose its bearing capacity.
No matter how carefully the top layer of soil is compacted, it will settle after concreting and the concrete floor may crack and damage the waterproofing of the foundation. The rotting of organic substances contained in humus would contribute to the further destruction of masonry and plaster. When digging out the soil, try to avoid loosening, soaking and freezing of the foundation trim so as not to disturb the homogeneity of the soil. Do not excavation in Toronto before the beginning of winter, as the working soil layer is destroyed by frost and loses its bearing capacity. In addition, the destroyed soil should be removed before concreting the foundation, which means extra work and excessive use of concrete. If the foundation is not concreted immediately after the excavation, the soil is not removed by 10-20 cm (depending on the type of soil). This layer should be removed immediately before concreting.
If there is water in the pit, it must be removed or dredged. The opinion that it is enough to mix the concrete mixture dry and pour it into the water is wrong: instead of concrete in the foundation trench there will be no glued stone mass. The vertical walls of deep pits should be reinforced with a sheet pile fence.
In bonded soils, the walls of the excavation may be vertical and in loose soils, they must be sloped. The angle of slope depends on the type of soil, it is larger in strong soils and smaller in weak soils. If the excavation depth exceeds 2 m, the sloping walls should be strengthened with a 40-50 cm wide slope.
If a waterproof scaffolding is installed before the basement masonry is erected, the dimensions of the excavation in Toronto can be reduced by 60 cm on each side, i.e. by the width of the scaffolding.
If it turns out that the excavation in Toronto or the trench is deeper than necessary, the sand-gravel mixture must be sprinkled to the required depth: care must be taken to ensure that there are no areas with different bearing capacities, i.e. with different precipitation in the future. When it is necessary to excavate the soil from the existing masonry in order to regulate the area, it must be dug in a way that does not disturb the protective layer. Otherwise, the ground may freeze under the foundation trench.
The trench under the foundation for external supporting walls is dug to a depth of at least 80 cm, which is necessary to protect the working layer of soil under the foundation's sole from freezing. For bonded soils in which groundwater is at a depth of less than 2 m, the depth of the foundation should be increased by 100-120 cm. The inner walls are frost-proof, so a sufficient foundation depth of 50 cm is required. It is better to ask those who have already built in the area or consult a specialist to determine the optimum depth of the foundation.
The foundation should be backfilled before winter to avoid freezing of the ground in the foundation trenches. For backfilling it is not allowed to use garbage, broken ceramic pipes, fragments of reinforced concrete elements, trimmings of sheet steel, quicklime remnants (which are then quenched in the ground), etc. If there are such pieces, it is impossible to press backfill, and water accumulates in the voids, which can subsequently penetrate under pressure into the masonry by cracks in the insulation. It is very dangerous to have solvent residues in the backfill, which destroy the foundation's insulation coating. The backfill material should be tamped in layers no thicker than 30 cm. Buildings erected on a gently sloping slope should not be backfilled with sand-gravel mixture, because it will often be saturated with flowing surface water, which can penetrate through the insulation. Drainage is recommended at some distance from exterior walls.