Basement Underpinning Terms to Understand

Basement underpinning is an extremely responsible stage of the construction of any building. Not only the comfort of living in the house but also the strength and durability of the building depend on how qualified the work will be. Knowing how to pour a foundation properly will allow you to avoid critical errors in this case. To make a house reliable and durable, it is important to do the basement underpinning correctly. It does not matter how many floors the house will be, or what building materials you plan to build it with, it depends on the quality of the foundation and whether the structure will remain in perfect condition after many years. The first thing to do is to choose the type of basement.

Types of Foundations

Post: This is a row of concrete posts located around the perimeter of the house. Pouring of such a foundation is carried out in excavations dug in advance for the pillars. The pillars are then connected with beams.
Pile: This is made in the form of bored piles, which are driven into the ground and connected. It is important to drill holes in the ground to such a depth as to reach the hard rock;
Plate: This is mounted entirely under the entire house, with its dimensions exceeding the area of the walls of the building. To reinforce the slab, a grid of metal reinforcement will be required. For the arrangement of such a load-bearing structure will have to purchase a large number of building materials. Plate foundations are also an ideal solution if you live in an area with high seismic activity, or the soil on the site of problematic, or need to build a house on quicksand;
Strip: This is the most popular and versatile, in addition to being durable. Its main advantage is that in this case, it is possible to arrange a basement. In addition, this foundation is suitable for buildings of any story.

Before you start underpinning the basement, it is important to make preparations. First, the construction site is cleared of all kinds of debris, remove old trees and bushes, uproot stumps, and remove dry grass. To make the whole site used as efficiently as possible, you need to competently zone it. The entire area of the site should be leveled if possible, before building a house and underpinning the basement.

Preparations

Determine the house location and mark the base.: The foundation must be straight, no deviations in width, length, or diagonals are allowed.
Choose the dimensions of the foundation: Consider its width, and depth. The width must exceed the thickness of the walls by 10-20 cm.
Mark the slab foundation: It will be made in the form of slabs located under the house.

In addition, the foundation must be leveled, there should be no deviations in width, length, and diagonals. For this reason, it is extremely important to properly mark the construction site. To make a marking for the basement underpinning, you will need a cord, fishing line or twine, some wooden pegs to mark the borders, a tape measure, a plumb line, and an angle with which you will measure. After that, choose how the house will be located, to do this in one of the proposed corners of the front of the building hammer pegs. Further algorithm of actions: from the first driven peg measure the width of the foundation, set the second lighthouse. Set the vertical from the first corner with a plumb line. From the vertical, pull a cord perpendicular to the line of the proposed facade. Using the angle, determine the last corner of the building, hammer in a peg. When the outer perimeter will be marked, begin to build the inner. Near the pegs hammer in a peg, the distance between them is equal to the thickness of the base of the house. Between the pegs pull a cord. If any deviations are found, change the position of the pegs.

Excavation

Before you start pouring the foundation of the house, you have to prepare a trench or excavation. You can hire special equipment to excavate the soil. However, this can be expensive, and often such trenches are crooked, which in the future will lead to the wrong location of the foundation. Another way is to do the excavation work with your own hands, using shovels. It is also possible to hire a team of builders, like WillFix, who will do everything necessary in a couple of days. This option is the best because the pit or trench will turn out flat, and you can immediately begin work on pouring the foundation.

Sand Cushion Construction

Among the mandatory stages of basement underpinning is the preparation of the bed. The need for this step is explained by the fact that, depending on the soil, the distribution of moisture can occur unevenly across the height and width of the construction site. In particular, this applies to heaving soils. The sand cushion should be 20 cm thick, it should be watered and tamped. The sand should be distributed evenly throughout the foundation. On top of such a pillow should be filled with gravel or crushed stone of a large fraction.

Making Formwork

The formwork can be made of the following materials: boards with a width of 100-200 mm and a thickness of 25-50 mm, moisture-resistant plywood or OSB boards, metal sheeting, or slate or corrugated board. It is important that the formwork is strong and reliable and can withstand the pressure of the concrete after the foundation is poured.

Reinforcement

Reinforcement is used to create a high-strength foundation when pouring the foundation. It is used to make a reinforcing frame. It is a spatial structure of the corrugated reinforcement, which diameter is 12-16 mm. To connect the rods, knitting wire is used. The reinforcing framework for the slab base is made in the form of a two-row horizontal grid, the size of the cells is 20 by 20 cm. They are also installed on stands, as the reinforcement should be covered with a protective concrete layer.

Preparation and Pouring

Before starting the construction work, it is important to calculate the material requirements for pouring the foundation by determining the required volume of the concrete mixture. It is necessary to know the volume of each strip, and then add up the obtained values. How do you make foundation mortar? There can be several solutions such as buying a concrete mixor using a concrete mixer or your own hands to make a mortar on the site and perform the pouring of the foundation manually. The best option is to pour the foundation when the temperature is above zero. If you do this work in the fall or winter, the strength of the structure will decrease. When the composition is poured, it must be compacted with a deep vibrator, and then smooth the mixture so that the surface is flat without depressions and heaps.

Common Mistakes

The same belt width under the walls.: Depending on the thickness of the wall the pressure on the foundation will be different.
Insufficiently dense formwork.: Gaps in the boards or between the surface of the ground and the formwork can cause concrete to leak into the voids.
The concrete did not mature properly.: Before the composition reaches 75% of its design strength, it requires certain care.
Violation of construction technology.: If you decide to simplify the pouring procedure, the result of the work will be unpredictable.

To competently perform the basement underpinning for already constructing or planned houses, follow all the above recommendations. Observe the construction technology, and act consistently during the phases of the pouring. Then the construction will be durable and reliable, and the house will remain in its original form after many decades. If you make a mistake, it will be difficult to correct. So, if you are not confident in your abilities, contact a professional builder.