Foundation marking is the initial and crucial stage of construction. If the foundation marking is done incorrectly, the foundation's characteristics will be unpredictable. Therefore, it is important to know how to mark the foundation correctly, what to consider, and what tools to use for this task.
Incorrect
foundation marking leads to:
•
distortion of the geometric shape;
• reduction
in usable area;
• loss of
load-bearing capacity;
•
non-compliance of the foundation with the design.
If the constructed
foundation turns out to be larger or smaller than the design dimensions, the
pre-purchased floor beams, roofing, and other building materials will not be
suitable. Adjusting them will require additional financial investment. And if
the load on the ground is incorrectly distributed, reinforcement or complete
dismantling of the foundation will be necessary. For example, to reinforce
subsided monolithic slabs, specialists lift the slab with a truck crane, drive
in reinforced concrete piles, and tie them in place. Only then can wall
construction begin. This is a labor-intensive and costly process, but without
it, cracks will appear in the foundation and walls. The completed house will be
uninhabitable.
Preparation for Layout
Specialists
determine the optimal location for the house based on:
• The
wishes of the site owner.
•
Geological soil survey. A soil study is performed before layout; these
characteristics are crucial for drafting the house design and selecting a
foundation appropriate for the site conditions. If, during the work, a decision
is made to move the building to another part of the site, the soil study is
repeated. Soil composition can vary significantly in different parts of the
site.
•
Requirements for setbacks from site boundaries and other buildings. This
distance is regulated by building codes and regulations. Without meeting these
requirements, it will be impossible to register a building.
Debris is
removed from the site, trees are cut down, and tall grass is mowed. The site is
leveled. Excavation work is not performed for a pile foundation. Therefore, on
slopes or sites with difficult terrain, building a house on piles is more
cost-effective. Basic Tools for Marking the Foundation
The
following tools are required for marking the foundation:
• Tape
measure.
• Wooden
stakes or metal rods.
• Square to
check the angle at 90, 60, or 30 degrees.
• Rope.
• Building
level. For more precise measurements, professionals use a laser level.
Marking a Rectangular Foundation
Rectangular
and square foundations are the easiest to mark. However, it's important to
carefully mark the foundation to avoid having to adjust and level the finished
foundation later.
Marking
Procedure:
1. Mark off
the site boundaries and adjacent buildings at the distance specified by
building codes.
2. Drive in
two pairs of stakes.
3. Stretch
two parallel ropes.
4. Drive in
two more pairs of stakes and tighten the ropes to complete the outline. The
intersection of the rope at a right angle is the outside angle of the
foundation.
5. Measure
the two diagonals. If the diagonal distances from one corner to the other are
the same, the markings are correct.
6. Repeat
the process to mark the inside sides of the foundation and any additional
edges.
The
permissible error in the lengths of the sides and diagonals is 1 cm. Otherwise,
adjust the markings or repeat the markings.
Note: A
school geometry course is an excellent aid in marking out the foundation. In a
right triangle, the square of the hypotenuse is equal to the sum of the squares
of the legs. When marking, take the length of the diagonal and square it. This
value should be equal to the sum of the squares of the sides. If this condition
is met, the angle is indeed 90 degrees, and the foundation markings are
successful. Marking the foundation using a "spiderweb" pattern
An
alternative method for precise marking is to make a foundation template out of
rope:
1. Cut the
rope to the design dimensions of the sides and diagonals. The rope should not
stretch, otherwise the markings will be inaccurate.
2. Connect
the ends of the diagonals and sides at the corners.
3. Pull one
corner taut and secure it.
4. Secure
the remaining corners.
It is
important to ensure good rope tension. This will ensure that the opposite sides
and diagonals are aligned.
Specifics of Marking Different Foundation Types
Marking a
monolithic slab follows general rules. When marking the boundaries of a strip
foundation, stakes are driven in approximately 1 meter from the foundation
boundaries. This ensures they remain securely fixed in the ground and do not
shift during trench digging. For a pile foundation, specialists designate not
only the installation locations and the planned height of the pile above the
surface, but also the horizontal plane for the grillage.
There are
several methods for accurately marking out the foundation. Regardless of the
method, it's important to constantly monitor and, if necessary, adjust the
ratio of the diagonal and side lengths. The reliability and compliance of the
foundation with your design depend on the quality of the markings.
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