4 Steps to Make a Wall Foundation
Focus on foundations
Step 1: Locate the foundation on the ground
Step 2: Dig the foundation
Step 3: Place the reinforcement
Step 4: Prepare and pour the concrete
Foundations are the basis of all constructions; they ensure the structure’s durability over time by distributing the weight of the building evenly on the ground.
If it is essential to ask for advice from a professional, a geo technician, for major construction, you can dispense with it for the foundations of light structure and if the ground does not comprise particular difficulties (sloping ground, impermeable ground, etc.).
Determining its location, digging, making concrete, and filling the excavation are the essential steps to applying the foundations for a wall.
Dimensions of the foundation
A superficial foundation or footing is sufficient in stable and hard soil for a light and low construction.
The dimensions of the foundation are defined according to the following principles:
The foundation must be frost-free; its depth is determined according to the region. The thickness (or width) of the foundation is equivalent to twice the width of the wall if it exceeds 1 m in height. However, the minimum thickness of an unreinforced foundation is 30 cm. On the other hand, if the consistency obtained by calculation is too important, it is preferable to make a reinforced foundation: this reduces the cost and improves safety.
For example: for a low wall made of cinder block 1 m high and 20 cm wide, the foundation must be about 40 cm wide.
1. Locate the foundation on the ground
At the precise location of the future wall and each end, plant wooden stakes (cleats) at the corners.
Prepare wooden “chairs” or porticos by nailing two cleats to the ends of a crosspiece formed by a third cleat. Make an entrance for each end of the wall. The entry should be wider than the foundation.
Make notches in the crossbeam that match the width of the foundation.
Connect the chairs with cords stretched between the notches.
Mark the precise line of the foundation on the ground from the strings, using a plumb bob and spirit level.
Note: you can mark two additional notches on the crossbeam corresponding to the width of the wall and then stretch the lines to mark the location of the future wall.
2. Dig the foundation
You can dig the foundation with a shovel and pickaxe if the foundation is shallow and short enough.
If the soil is complex and the foundation large, use a mini-excavator (for rent).
Be precise and regular: follow the foundation’s path carefully and dig plumb walls. Check with the plumb line.
Place stakes to mark the depth at each corner. Once the depth is reached, carefully tamp the soil to level it.
Note: Place boards on the sides to serve as footing forms if the footing is wide.
Check with a spirit level.
Caution: once the excavation is done, do not delay pouring the foundation because if it rains, the work will be damaged, and you will have to start over.
3. Put the reinforcement in place
On the bottom of the excavation, place a gravel bed with a large grain size of about 10 cm thick.
Smooth the gravel bed.
Place 4 cm thick shims on the gravel bed to raise the reinforcement.
Note: the reinforcement must always be covered with concrete to a minimum thickness of 4 cm.
Lay your footing reinforcement. The reinforcement elements are tied together with wire. Observe the minimum distance of 4 cm from the edge of the foundation.
4. Prepare and pour the concrete
Prepare concrete with a dosage of 300 kg/m3 in the concrete mixer.
Pour the concrete into the foundation with a wheelbarrow.
Once the concrete is poured, compact and smooth the surface of the concrete with a board or a float so that it is perfectly level and flat.
Let it dry for about 48 hours before building the wall.
Below is a shortlist of the materials needed to make a foundation.
Thick protective gloves