Shallow strip foundation with your own hands: calculation of the structure and step-by-step instructions for manufacturing

For many homeowners, building a shallow strip foundation themselves is a doable task. For lightweight buildings like garages, tiny houses, or garden sheds, this kind of foundation is perfect. It is a less expensive and labor-intensive option because it requires less excavation than deeper foundations.

It’s critical to precisely determine the dimensions and materials required for your foundation before beginning construction. A well-planned structure guarantees stability and longevity. You’ll have to take into account things like local building codes, soil type, and load-bearing capacity.

There are several important steps in the methodical process of constructing a shallow strip foundation. The preparation of the site, the foundation’s marking, trench excavation, formwork installation, concrete pouring, and foundation curing are among them. Carefully following each step is necessary to guarantee a sturdy and dependable foundation for your building.

We’ll walk you through every step of the procedure in this post, providing helpful hints and thorough instructions. Our aim is to simplify and make the process of building a shallow strip foundation accessible to all skill levels of do-it-yourselfer.

Scope, pros and cons

Advantages of this type of foundation

The primary benefit of the MZLF is that it can be assembled by hand without the need for sophisticated lifting machinery.

Selecting this design requires less excavation work than selecting a different one. This kind uses less materials than other solutions. It is possible to build it in seismically active regions.

Disadvantages of the MZLF

Strict guidelines for implementing the technology and design constraints are two drawbacks of MZLF:

• it is not recommended to make such a foundation if there is a difference in height at the construction site, as well as on peat bogs and clay;
• this option does not support heavy houses;
• concrete maturation leads to delays in work;
• no basement in the house.

Design features

The foundation’s structural component is a single, pre-cast concrete slab placed in a trench. A power frame consisting of 10–12 mm diameter ribbed reinforcement bars sits at the base of the slab.

The power frame’s upper and lower planes are lined with longitudinal bars. This configuration guarantees that vertical loads won’t bend the object. Subsequently, they are joined to brief transverse and vertical sections of reinforcement.

The frame is constructed with long bars to reduce the amount of joints. If required, the rods are joined together with a 200–300 mm length overlap and secured with soft knitting wire. The frame is not made using welding since it can lead to corrosion. Resistance to bending forces is increased by reinforcement.

The ends of the at least 400 mm long rods that extend past the size of the wall are bent at a right angle at the foundation’s corners. For wooden houses, the frame is filled with liquid concrete mix grade M200; for brick houses, it is filled with grade M250.

It is advised to place the reinforced concrete slab on screw or bored piles when constructing a structure on challenging soils. On the construction site, bored piles are created; screw piles are removed from the factory. Similar to the working frame, they are joined structurally by reinforcement and filled with concrete. The piles are attached to the main frame prior to pouring.

Around the building, water builds up as a result of summertime torrential rains and snowmelt in the spring. Thus, a drainage system and an insulated blind area are set up in order to dry out the construction site.

In the plan, the trench sides are drawn slightly longer than the future house’s measurements. Its width is 600 mm, and its depth is roughly 500–700 mm. The tape measures about 500 mm in width.

Sand and crushed stone layers are alternately poured to a thickness of 200–300 mm to form a cushion at the bottom of the trench. Layers are pushed together. The formwork is ready to receive the solution pour.

Calculation of the MZLF

Two procedures must be carried out in order to construct a construction site competently: determining the size of the concrete strip and researching the characteristics of the site’s soil.

Depth of laying

The trench needs to be excavated to a depth of 250–300 mm beneath the solid clay layer’s upper edge. The total thickness of the cushion and the slab determines its depth.

Width of the monolithic tape

The working formula takes into account the weight of the future home, including its contents and occupants, the material of the walls, the properties of the soil, and the weight of the winter snow on the roof.

The estimated soil resistance value is used in the formula. Only experts from a specialized laboratory should determine this indicator. A private builder will be able to calculate the remaining dimensions on their own once they know this coefficient.

Height above ground level

The upper plane of the concrete slab can either rise above the site, serving as the building’s base, or it can protrude slightly above the surface, matching the site’s ground level. A floor that is elevated above the ground is more resistant to cold and moisture. It is important to keep in mind that the strip’s height above the ground shouldn’t be higher than its width.

Calculation of the shallow foundation on heaving soils

Soils that swell in colder temperatures and when saturated with moisture are known as heaving soils. The wintertime freezing of moisture causes an uneven expansion of the soil’s volume. Local deformations lead to randomly distributed stresses in the concrete monolith, which can result in the slab warping and possibly developing cracks.

When building a foundation on heaving soils, there is a requirement that must be fulfilled regarding the foundation’s base location.

It needs to be 50 centimeters above the moisture level of the earth. Furthermore, it is a good idea to use a set of building techniques that shield the foundation from soil heaving.

Among them are:

• making a foundation cushion from non-heaving material;
• arranging drainage in the horizon of the base of the strip;
• waterproofing the side surfaces of the foundation;
• insulating the blind area;
• creating a storm drain on the site.

It is best to load the new foundation to capacity prior to the arrival of the winter cold. If not, it needs to be covered with insulation and stored for the winter.

Foundation device – construction technology

Building a shallow foundation for a rural home involves a few necessary steps in technology:

• development of a set of technical documentation for the construction, including a general view of the future building, floor plans, drawings of the reinforcement frame, a specification of the necessary materials;
• preparation of the construction site – clearing and cleaning, drainage of water using channels;
• delivery of building materials;
• marking and digging of a trench, preparation of a cushion of sand layers and crushed stone layers;
• manufacture of formwork;
• manufacture of a reinforcement frame;
• pouring concrete;
• vertical waterproofing of the foundation;
• construction of an insulated blind area.

Maintaining the production process’s continuity is one of the needs of appropriate construction technology.

When there are enough laborers and a complete supply of building materials on the job site, it is completed.

Installation of MZLF – step-by-step instructions

Using the step-by-step instructions will ensure that nothing is missed during construction and that all necessary work is completed with high quality in the shortest amount of time.

Preparatory work and marking

Draw the house’s foundation plan on the construction site. Place fasteners into the corners of the upcoming structure and draw the construction cord. This will designate the concrete strip’s outer bound. In the same manner, mark the foundation’s inner perimeter. Keep in mind that the trench’s shape needs to match the formwork as you draw its lines.

Arrangement of the trench and cushion

According to the estimated dimensions, dig a trench. The width can be somewhat expanded if the soil is loose. Examine the geotextile-lined trench to shield the cushion from the surrounding ground.

Sand and crushed stone layers should be placed on the bottom in succession to create a cushion. Every layer has a thickness of 200–300 mm. After adding water, tamp each layer of sand. Apply a thin layer of liquid cement solution to every layer of crushed stone.

Dig pits in the locations where stairs or stove installations are planned inside the home.

Installation of formwork and reinforcement

In the trench, install the formwork. Take even, smoothly planed boards for its manufacture. To prevent the formwork walls from being pushed outward by the poured concrete, place supports on the outside of the formwork and tie ties on top of the walls.

Construct and attach the reinforcement framework. Since there will be more room in the trench, it is preferable to tie the reinforcement before putting in the formwork.

Pouring concrete

Transfer the mixture. A mixture that was made in the factory and transported in a mixer to the location is one that has been properly prepared. Use a mobile concrete mixer if it is not possible to transport it in a mixer. It is best to pour the foundation in its entirety at once, without taking extended breaks.

Layer-by-layer pouring of the foundation

Parts of the solution are poured. To get rid of air bubbles, vibrate each portion that has been poured. If there isn’t a vibrator, pierce it several times throughout the pouring with an iron rod.

In around five days, the concrete sets. A month after pouring, complete hardening is accomplished. After a week, the formwork can be taken down. To keep dust off the poured foundation, cover it with polyethylene film. Water it in hot weather to keep it from cracking.

Insulation of a shallow foundation

Insulation of the foundation must begin at the very beginning of its construction. The foundation will endure longer, to start. Second, by taking these steps, the first floor will be shielded from moisture and cold. The house requires less money to heat. Vegetables and other products can be stored in the basement, where condensation won’t build up.

Thermal insulation materials include polystyrene foam, polyurethane foam, penoplex, and special bulk mixtures. Often used as a bulk material in conjunction with a waterproofing additive is expanded clay.

Special adhesives are used to adhere slabs of penoplex and polystyrene foam to the walls. On the exterior of the house, the slabs are glued vertically, and on the interior, they are laid horizontally. This adds another layer of defense against the ground beneath the foundation freezing.

Liquid polyurethane foam is utilized. It forms a continuous, seamless coating after coating, filling all the pores.

With the correct advice, building a shallow strip foundation on your own is a task that is doable. This article includes all the necessary information, including how to calculate the structure’s dimensions and how to build it step-by-step. We’ll streamline the procedure so that even novices can understand it. You’ll discover how to level and stabilize the foundation, mix and pour concrete, construct formwork, and prepare the site. You won’t need expert assistance to lay a solid foundation for your construction project if you adhere to these simple and straightforward instructions.

Features of the construction of shallow strip foundations on heaving soils

A foundation built on heaving soils needs to have its base below the freezing point of the soil. However, the cost of construction goes up with this solution. Complete safety precautions are marginally less expensive.

Among the actions on the list are:

• making a cushion under the foundation from a non-heaving material;
• arrangement of a drainage system in the same horizon with the base of the foundation;
• insulation and waterproofing of vertical planes of the foundation;
• insulation of the blind area;
• drainage of storm water.

The summer is when all construction projects must be finished. Before the cold weather arrives, the foundation needs to be completely loaded.

Step	Description
1. Site Preparation	Clear the area of debris, vegetation, and obstacles. Mark the foundation layout using stakes and string.
2. Digging the Trench	Excavate the trench according to your layout, ensuring it is the correct depth and width.
3. Installing the Formwork	Place wooden boards along the trench sides to shape the foundation. Secure them firmly.
4. Laying Gravel and Sand	Pour a layer of gravel at the trench bottom for drainage, then add a layer of sand to level the base.
5. Reinforcement	Place steel bars or mesh in the trench for added strength. Secure them in place.
6. Pouring Concrete	Mix concrete and pour it into the formwork, ensuring an even distribution. Use a vibrator to remove air bubbles.
7. Leveling and Smoothing	Level the surface with a screed and smooth it out using a trowel. Allow the concrete to cure properly.
8. Removing Formwork	Once the concrete has set and cured, carefully remove the formwork.
9. Waterproofing	Apply a waterproof membrane or coating to protect the foundation from moisture.
10. Backfilling	Fill the excavated area around the foundation with soil, compacting it as you go.

You can enhance the value and stability of your construction with a gratifying project by building a shallow strip foundation on your own. You can build a solid foundation that will support your structure for many years if you take the proper measures and have the right supplies and equipment.

To guarantee that the foundation is appropriately sized and able to support the weight of your building, precise calculations are necessary. Correct planning and measurement save money, guarantee the project’s longevity, and prevent costly errors.

The foundation construction process is made simpler by adhering to a methodical approach. You may manage the project more skillfully and produce results that are on par with professionals if you break down each phase, from formwork and excavation to concrete pouring and curing.

For many do-it-yourselfers, however, building a shallow strip foundation is a practical and doable project. You can successfully finish the foundation and proceed with confidence in your construction project if you pay close attention to detail and follow the instructions.

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