The durability of the building and the safety of its operation depend on the reliability and stability of the foundation foundation. Based on this, the correct choice of the supporting structure becomes one of the most important conditions in the construction of buildings, baths and outbuildings.
Pros, cons and conditions of use
There are several options for the construction of foundations, but the most common for low-rise residential buildings is the foundation of the tape type. This is due to the optimal ratio between performance and financial costs for its construction.
As a result, other types of foundation structures are used only if the tape cannot provide guaranteed stability of the building. For example, on heaving soils or at a high level of groundwater. One of the best alternatives in such cases will be a reinforced concrete slab. Therefore, we will try to understand the question of which foundation is better, a tape or a monolithic plate, comparing their technical characteristics, construction time and financial costs.
Strip foundations
This type of foundation is a continuous concrete strip, arranged under each wall and immersed in soil at a design depth. She perceives weight loads from the building, evenly distributes them and transfers to dense layers of soil. The parameters of the tape are determined by the following design indicators:
- reference width;
- height;
- depth of laying;
- construction material.
According to the depth of the foundation, a shallow, shallow and deepened strip foundation is distinguished. The first type of foundation is used on especially dense, rocky and rocky soils. The second - on dry non-porous soils. A full-fledged full-depth tape rests on dense layers below the standard point of soil freezing depth.
As a material for the construction of a strip base use:
- prefabricated reinforced concrete blocks;
- rubble stone;
- full clay brick;
- reinforced concrete.
In addition, you can find combined options for the use of these materials and pile-tape structures.
The main advantages of tape structures are:
- simplicity of construction;
- relatively low cost of construction;
- good bearing capacity;
- strength, reliability and durability;
- the presence of several design solutions;
- the possibility of arranging a basement or basement.
The disadvantages include:
- the need for hydrogeological surveys;
- a large amount of earthwork;
- the existing probability of subsidence of the foundation with a high level of groundwater, as well as on weak and heaving soils.
It should be noted that similar disadvantages exist for other types of foundation foundations. Modern construction technologies can reduce the risk of error and avoid damage or displacement of the belt support.
Monolithic plate
This type of foundations is made in the form of a monolithic reinforced concrete slab, poured onto a rammed sand and gravel pillow (the construction is discussed in more detail here). Layers of thermal and hydraulic insulation are also contemplated. Due to the large area of the structure, the weight load from the building and the foundation itself is evenly distributed and in a specific ratio is small. At the same time, the reinforced concrete monolith is able to move freely on the surface of the soil during its movements, without collapsing and providing reliable support for construction.
According to the type of construction, continuous and ribbed plates are distinguished, as well as a box or Finnish, the flat monolith of which is combined with a shallow strip foundation.
For the construction of a slab base, builders:
- remove the topsoil;
- tamping the surface;
- sand and gravel pillow fall asleep and condense;
- spread geotextiles;
- lay a layer of insulation made of polystyrene foam;
- establish the formwork;
- mount a reinforcing cage;
- pour concrete mixture over the entire surface.
The construction of walls begins only after hardening of concrete at 70-75%, which occurs in 2-3 weeks. As a result, the construction of the house is carried out on a solid, insulated foundation, resistant to possible movement of the soil.
Among the main merits applications of a monolithic reinforced concrete slab as a foundation for a residential building include:
- the possibility of building buildings on almost all types of soil;
- high bearing capacity due to the distribution of weight loads over a large area;
- ensuring the stability of the building during ground movements;
- simplicity of design, eliminating the risk of serious construction errors;
- use of a plate as a floor of the first floor.
In list cons experts call:
- lack of a basement or cellar in the house;
- the impossibility of carrying out repairs;
- high consumption of building materials;
- a significant amount of earthwork requiring the use of special equipment;
- high cost of construction.
However, these shortcomings become fully justified in those cases when, due to weak and unstable soils, alternatives simply do not exist. In this case, the answer to the question, which is better - a slab or a strip foundation, becomes unambiguous.
Comparison
To determine which is better, a monolithic slab or a strip foundation, we will compare the structures by such indicators as:
- construction cost;
- reliability and durability;
- simplicity and speed of construction.
However, it should be noted right away that a comparison of two fundamental technologies cannot be called correct. The use of tape structures is limited by the presence of weak unstable soils, and the high cost of installing a floating slab is not justified on dense stationary soils.
Which is cheaper
Construction practice shows that strip foundations, especially with shallow deepening, are several times cheaper than reinforced concrete monolithic slabs. This is based on less excavation, construction materials and labor. Therefore, if possible, builders always choose the foundation of the tape type, because it is more profitable.
What is more reliable
The reliability of the base depends on the type of soil, the depth of its freezing and the upper level of groundwater. Strip foundations without additional reinforcement cannot be built on heaving soils and wetlands. A monolithic foundation of a slab type can be equipped under almost any conditions. Therefore, it can be considered more reliable.
What will last longer
Experts say that a monolithic reinforced slab can serve as a base for up to 150 years. However, construction companies rarely give a guarantee for a slab foundation for more than 25 years. Accurate data and examples are not yet available, as this technology was developed relatively recently.
The tape base poorly perceives both vertical and horizontal ground displacements. Therefore, for precast tapes, contractors define a guarantee of 30 years, and for reinforced concrete monoliths for 50 years.
What is being built faster
When pouring a monolithic tape or plate, a large amount of time is spent on the hardening process and the establishment of sufficient concrete strength. True, the use of ready-made foundation blocks or floor slabs can reduce the duration of construction, but such designs are less reliable.
In both cases, the installation of formwork, assembly of the reinforcing cage, waterproofing and pouring the mixture is required. Therefore, we can say that the speed of construction of both types of foundation depends on the length of the walls and building area.
Brief Comparison Results
As a result of the consideration of the issue, we can say that a monolithic foundation slab is stronger and more reliable. However, in practice, builders prefer a cheaper tape, because cost-effectiveness and lower costs are a decisive factor in choosing the construction of the base of the house.
In addition, existing traditions require a basement or cellar, the arrangement of which when filling the slab becomes impossible. Therefore, the final conclusions can be made on the basis of rationality, technical conditions, economic feasibility and which foundation is cheaper.