When can a strip foundation be used?

You can look through the building regulations to find out conditions under which strip foundation can be used. Note the following in detail:

1. When planning the construction, consider the required width of the foundation strip denoted in building regulations.
2. The concrete solution should meet the requirements of compatibility with the soil chemicals.
3. The thickness of the concrete strip should equal to or exceed the projection of the external side of the wall, but not less than 6 inches.
4. The step height shouldn’t exceed the thickness of the foundation.
5. The foundation strip protrudes beyond the edge of piers, chimney forming side of the wall as much as it protrudes beyond the exterior surface of the wall.

Partitioning

Remove debris from the place and start partitioning by putting on the ground both external and internal borders of the future foundation. Use pegs or reinforcement bars and ropes.

When marking is done, you should explore variations on the surface of the construction site and select the lowest point to refer to when marking depth of the trench and to eliminate difference in the foundation height.

Preparation for construction of a strip foundation

1. When the trench is ready, fill in a sandy base supplemented with gravel on the bottom.
2. Foundation formwork is made of planed boards with a thickness of approximately 40-50 mm. When erecting the formwork, you should monitor its verticality all the time. The recommended projection of the frame above the ground is 12 inches. It is necessary to build a small base.
3. The next step is building foundation reinforcement. Reinforcing bars with 10-12 mm section are bound with specifically designed binding wire so that the sides of square cells were equal to 12-16 inches. For the reinforcement you can use either steel or fiberglass reinforcing bars. When placing the reinforcement in the trench, watch indents from the edges. Optimum padding is 50 mm. In this case, the reinforcement will be most effectively located in the monolith.

Pouring concrete strip foundation

Pouring concrete is carried out immediately in the case of ready-mixed concrete or in layers, if the concrete is prepared independently.

1. Preparation of concrete: cement is mixed with sieved river sand in the ratio of 1:2 – 1:2.5, and diluted with water to a liquid cream consistency, after which it is poured onto the prepared gravel. The amount of rubble corresponds to that of sand. Stir the mixture so that all the rubble got moistened with a solution.
2. Pour the concrete into the prepared formwork. Pierce the concrete in several places using a metal bar and compact it with a wooden block to remove the remnants of the air from the voids.
3. Pour the concrete to the level indicated on the formwork. Thus rattle the formwork from the outside for better slump of concrete.
4. The top layer is aligned with a rule or trowel.
5. Dust the concrete with sifted dry cement; you can do it through a sieve. This method lets top layer of concrete harden a bit and prevents its erosion and cracking.
6. Cover the concrete with burlap or covering material and leave for 3-4 weeks. In dry weather, you need to moisten the top layer of concrete to prevent it from drying out.

This video has nicely demonstrated about the detailed calculation step by step

Source

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