What is cheaper and which foundation is better – strip or monolithic slab + their advantages and disadvantages

Selecting the appropriate foundation is one of the first and most important decisions in the planning of a construction project. Because the foundation holds up the entire structure, choosing the best and most affordable option is crucial. Strip foundations and monolithic slab foundations are two common options, each with pros and cons of their own.

For structures having load-bearing walls, strip foundations—also referred to as footing foundations—are frequently utilized. They entail the placement of concrete strips beneath the walls to offer stability and support. This kind of foundation is popular for many residential projects since it is frequently less expensive and easier to install. But it might not work well in all kinds of soil, and under some circumstances, it might not be as resilient.

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What is a strip foundation

A strip foundation is a thickened strip that is submerged in the ground and serves as support for both internal and external load-bearing walls. It absorbs the building’s weight and disperses it equally, shifting the load onto the soil layers.

The groundwater level (GWL), the composition of the layers, and the load-bearing capabilities of the soil all directly affect the tape’s thickness, height, and immersion depth.

The following primary factors impact the soil in the belt:

• Composition, homogeneity of structure.
• Deposition level and presence of layers of soil water.

There is interaction between the two factors. Clay soil is the most problematic type. Water cannot pass through it, but it can accumulate in the pores, increasing the risk of heaving in the winter when frozen water expands and shifts the ground’s elevation.

Heaving loads cause the foundation to deform because they act unevenly and at different places. Furthermore, these forces are not constant and may sporadically occur in various parts of the supporting structure.

Immersing the tape below the winter freezing level is the solution to the issue. Heaving loads do not arise from below in these circumstances, but the developed lateral surface of the belt is subjected to considerable forces in the horizontal plane.

A shallow type of strip foundation that is submerged between 0.5 and 1.5 meters is used to lessen these loads.

There is a decrease in horizontal lateral loads and a collective compensation of forces from below:

• Weight of the building.
• No freezing of the soil under a heated house.
• A layer of sand backfill that performs drainage functions and takes on frost heave loads.

There are fewer special challenges in making the tape because of its straightforward design, which lowers the possibility of construction errors and disasters.

Pros and cons

The tape has the following benefits:

• High bearing capacity.
• Strength, reliability.
• Resistance to external loads.
• Simplicity, cost-effectiveness of construction.
• The presence of several design options that allow you to optimally match the existing conditions.
• Possibility of arranging a basement or cellar.

The drawbacks consist of:

• The need for a thorough examination of the hydrogeological conditions of the site, the composition of the soil layers, and other features.
• A fairly large volume of earthworks, for which it is often necessary to involve construction equipment.
• The mass of the tape is quite high and concentrated on one line, which contributes to soil subsidence during unscrupulous construction.

Most types of foundations have some degree of existing flaws, so we’ve learned how to deal with them or prevent them from happening.

Kinds

Tape bases vary in a few ways.

There are varieties based on depth:

• Non-buried. Almost the entire tape is located on the day surface. It is built in conditions where immersion in the ground is impractical or impossible – on dry dense soils, rock slabs, etc.P. In practice, it is rare, since appropriate conditions in northern latitudes are almost impossible.
• Shallow. Used on dry, non-heaving (or slightly heaving) soils. Used for the construction of relatively small buildings, low-rise residential private houses.
• Recessed. A full-fledged type of tape is intended for large and massive buildings. It has the greatest load-bearing capacity and strength, but requires a lot of labor and consumption of building materials.

By way of tape layout:

• Monolithic. It is a continuous strip of reinforced concrete. Has maximum strength and load-bearing capacity, has high resistance to heaving loads. The disadvantage is that the concrete needs to be cured to gain technological strength, which takes a month.
• Made. The strip is built from special foundation blocks (FBS), brick, stone, etc.d. This option is only suitable for non-heaving soils with no deforming effects. The most durable tape is made from FBS; as the size of the fragments decreases, the resistance to the deforming influences of the soil decreases. Advantageous in appropriate conditions due to high construction speed.
• Combined. An example of such a foundation is the pile-tape type. A combination of two types of support is formed when the piles provide contact with dense and stable layers of soil, and the tape accepts and redistributes the load from the walls of the building. Used in difficult conditions, in heaving, loose or marshy areas. Construction requires the use of special equipment.

The sole, the foundation’s supporting component that is employed under specific circumstances, can also have a variety of design options.

What conditions is it suitable for?

Although belt bases can be used in many different environments, their optimal performance is achieved in stable, dry, and dense soils with low groundwater levels.

The hydrogeological conditions of the site lead to an increase in problematic positions, which decrease bearing capacity and necessitate additional measures such as installing a durable base (footing), increasing the backfill layer, and improving drainage. Strip foundations are used sparingly on heaving soils, and only in situations where design capabilities are at hand.

The base can withstand low temperatures quite well, but it needs to be isolated from condensate and groundwater by means of insulation and waterproofing.

Strip foundations are the primary base design option for the majority of our country, indicating their dependability and versatility.

A building’s type, cost, and soil conditions are among the factors that determine whether to use a monolithic slab foundation or a strip foundation. Strip foundations work well for lighter structures and stable soil because they are typically quicker and less expensive to install. They might not function well, though, on shaky or uneven ground. Although monolithic slab foundations are more costly, they offer better strength and stability, making them perfect for larger structures and difficult soil situations. Because each type has benefits and drawbacks, the best option will rely on the particular requirements of your project.

What is a monolithic slab

A house built on a solid reinforced concrete slab is known as a monolithic foundation. Since the specific pressure is relatively low due to the large area, it does not create a significant load on the ground.

The rigidity of the concrete pad is adequate to guarantee a stable and level foundation for the building, even as it moves freely on the soil’s surface alongside the house.

A small pit is excavated during construction, and the top layer of soil is typically just removed. Next comes the creation, leveling, and compacting of a layer of sand backfill, followed by the layering of geotextile.

On top is a heater (mostly made of specialty polystyrene foam), and then the reinforcing cage and formwork are put in place. The slab is then kept until it reaches technological strength after concrete is poured.

Consequently, a robust and well-insulated base is created, capable of supporting the weight of the building and impervious to ground pressure.

Advantages and disadvantages

Having a monolithic base has the following benefits:

• Possibility to build houses on weak-bearing, heaving or water-logged soils.
• The high load-bearing capacity of the slab allows the construction of fairly large and heavy buildings.
• With proper reinforcement, the slab is able to withstand all impacts that can arise and disappear suddenly. All ground movements are perceived quite easily; the slab “floats” on the soil surface like a raft.
• The design of the slab is simple, which allows you to avoid serious mistakes during construction.
• Creating a slab immediately forms the floor of the 1st floor, which greatly simplifies further work.

Supporters of this technology assert that there are no flaws in the monolithic foundation.

This isn’t totally accurate:

• The slab does not allow for a basement.
• There is practically no possibility of repairing the base.
• The consumption of building materials and the volume of excavation work are very high.
• The cost of such a foundation is very high, which is one of the main limiting factors.

Since the circumstances in which a monolithic slab is used are frequently unsuitable for other options, the disadvantages are not overly severe.

Varieties

Different kinds of slab bases exist:

• Prefabricated slab. Consists of ready-made reinforced concrete slabs laid on a prepared site.
• Monolithic slab, which is poured directly on site.

Depending on the kind of construction, they differentiate between:

• Solid slab. Used for relatively light and small buildings.
• Ribbed slab. The sole of this base has stiffeners that firmly fix the supporting structure in the ground, not allowing to move horizontally. In addition, the presence of ribs contributes to a more even distribution of loads from the weight of the building.
• Box. A type of slab in which the ground floor floor is a separate floor and the surface of the slab forms the basement.

Because of the high cost of construction, slab foundations are not common in our nation, thus structural issues have not been well developed up to this point.

Suitable conditions

Slab foundations are meant to be used in areas with heaving, unstable, or wet soils.

In most cases, it serves as a backup plan for pile foundations in situations where special equipment cannot be delivered or used.

Slab foundations are an option if the depth of the dense soil layers is too great or if the piles’ length is insufficient.

Which one is better?

Discussing which foundation is superior is incorrect. Since each type is intended to carry out specific tasks under the right circumstances, one option may be preferred over another only in certain cases based on hydrogeological and other considerations.

It is impossible to make a clear statement about the benefits of any kind of support structure without taking the circumstances into consideration. On unstable soils, the slab floats freely, making it unsuitable for belt construction. However, when constructed properly, a strip foundation is far more affordable and efficient than a slab.

Which type is built faster??

You must hold onto the concrete for a specific amount of time after pouring a slab or strip. Although this significantly slows down construction, there is currently no way to accelerate it. Construction time is greatly decreased when prefabricated strips are created or ready-made reinforced concrete slabs are laid.

Furthermore, the construction of monolithic slabs or strips is severely limited by the fact that concrete can only be poured during the warm season; in contrast, prefabricated structures can be constructed year-round, albeit with certain limitations.

Consequently, the design of the base determines the speed rather than its type.

Soil types

Dry soils that are either non-heaving or slightly heaving are suitable for strip foundation.

It becomes less effective and has many harmful side effects under more challenging circumstances.

The most adaptable kind of foundation is a monolithic slab, which can be constructed in practically any setting.

Which is cheaper – monolithic or tape?

We can declare with confidence that the tape is several times less expensive than the slab in terms of cost because there is a significant reduction in the amount of excavation work, building material consumption, and labor expenditure.

Its financial profitability and popularity among builders are determined by this.

What is their service life??

Experts predict that a monolithic slab will last a very long time; some sources put it at 100 years. However, contractors guarantee the stove for a period of 15 to 30 years, raising questions about how long it will last.

These disparities could be caused by variations in technology, operational circumstances, and other elements influencing the composition and layout of the material. Since the technology is new, no statistics have been gathered, so there is currently no reliable and accurate data.

The service life is much more precisely defined for strip foundations. 30 to 50 years are allotted for prefabricated brick strips, ranging from 50 to 75 years for FBS. The anticipated lifespan of monolithic concrete strips is 150 years.

Summing up

In actuality, the strip foundation is preferred since it is a more affordable choice with a multitude of applications. The presence of a basement is mandated by home improvement traditions, and cost and economy play a major role in the decision.

While acknowledging the slab’s functionality, builders continue to favor the more affordable and conventional leta due to its well-proven construction and operation technology.

Useful video

You will discover in this video which is preferable, a monolithic slab or a strip foundation:

Foundation Type	Advantages and Disadvantages
Strip Foundation	Cheaper to construct initially, suitable for stable soil conditions. Disadvantages include susceptibility to ground movement, potentially requiring more maintenance over time.
Monolithic Slab Foundation	Offers better resistance to ground movement, lower risk of cracking, and can be quicker to install. However, it tends to be more expensive upfront and may require careful planning for plumbing and electrical installations.

The decision between a monolithic slab and a strip foundation is based on a number of variables, each of which has pros and cons of its own. Strip foundations are an affordable option for stable soil conditions, distinguished by their concrete-filled trenches. They equally distribute the weight of buildings, but proper drainage is necessary to keep water from accumulating.

However, monolithic slabs offer an uninterrupted, joint-free concrete base that is exceptionally durable and stable. They can lower the chance of structural damage and are perfect for expansive soils that move easily. However, because more labor and materials are required for installation, the costs may be higher.

Think about your structure’s load-bearing needs as well as the particular soil conditions when selecting a foundation. Strip foundations are a reasonable and cost-effective option for projects in regions with uniform soil types and moderate load demands. They manage construction costs while offering adequate support.

On the other hand, if the soils on your building site are expansive or unstable and need a lot of preparation, it might be worth it in the long run to invest in a monolithic slab. Over time, monolithic slabs’ strength and resilience can reduce maintenance requirements and structural problems, even with their higher initial costs.

In conclusion, depending on the particulars of your building project, both strip foundations and monolithic slabs have advantages. You can choose the best kind of foundation by carefully weighing the long-term maintenance needs, financial constraints, and soil stability. You can make an informed choice that guarantees the security, durability, and financial viability of your building project by considering these aspects in addition to expert advice.

Video on the topic

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