Which is better – strip or screw pile foundation

The stability and longevity of your project can be greatly impacted by the choice you make between strip and screw pile foundations when building a solid foundation for any kind of building. It is crucial to comprehend the distinctions between each type before making a choice because each has advantages and factors to take into account of its own.

Strip foundations, sometimes referred to as shallow foundations, are frequently utilized in building projects in areas where the soil is stable and able to support the weight of the structure. They are made up of an uninterrupted concrete strip that distributes the weight of the building over a larger surface area. Buildings with relatively light loads or those with ideal soil conditions can use this kind of foundation.

Conversely, screw pile foundations present a flexible substitute, particularly in regions with difficult soil characteristics like elevated water tables or uneven terrain. Steel piles are twisted or screwed into the ground to create these foundations until they reach a stable layer of soil. Because it doesn’t require as much excavation as traditional strip foundations, this method can be faster and less disruptive.

For buildings on stable ground, strip foundations’ affordability and ease of use are two of their main advantages. Compared to screw pile foundations, they require less specialized equipment and knowledge, which makes them the better option for many construction projects. Their usefulness, though, might be restricted in places with unstable soil or uneven terrain.

On the other hand, screw pile foundations are more versatile and can accommodate a greater variety of soil types, which makes them appropriate for more types of construction projects. They can be installed with little impact on the surrounding area, and they are frequently utilized in projects where traditional foundations might not be practical or where quick installation is required.

The decision between strip and screw pile foundations ultimately comes down to a number of variables, such as the soil’s stability, the building load requirements, the project’s schedule, and its budget. Through a thorough analysis of these variables and advice from a licensed engineer, you can ascertain which kind of foundation best suits the requirements of your building project.

What is a strip foundation

A strip foundation is a closed, ground-level supporting portion of a building’s internal and external load-bearing walls that is submerged to a specific depth. Concrete is cast directly onto the construction site using single components like stone, brick, or foundation blocks (FBS), or by combining several techniques.

The most popular kind, with the highest strength and resistance to external loads, is a monolithic reinforced concrete strip. All types follow essentially the same construction process; the only variations are in how the tape is made (which varies depending on the material).

Phases of construction:

• Site preparation – removing the top layer of soil, leveling horizontally, creating a flat plane.
• Marking the area using pegs.
• Digging a trench to a predetermined depth.
• Creation of a preparatory layer of backfill, equipment of a drainage system.
• Construction of the tape itself (the procedure depends on the material used)
• Waterproofing, insulation.
• Filling the sinuses, carrying out further work.

The source material affects the belt’s construction time as well. A concrete strip that is monolithic is the most durable option. The casting takes about a month to harden, and during the first ten days, watering is necessary to keep the humidity levels inside and outside the tape equal and reduce stress.

Other technologies exist for building a belt from prefabricated components, such as brick, FBS, and stone, which can expedite the process. The foundation’s strength and stability are marginally diminished, but construction is moving much more quickly.

Prefabricated strip foundations are a better option if the site’s hydrogeological conditions permit.

It’s important to consider the unique benefits of both strip and screw pile foundations as well as how well-suited they are for your building project. Strip foundations provide dependable and affordable support for standard structures. They are widely used because of their stability in supporting buildings on solid soil. On the other hand, screw pile foundations are very versatile and can be quickly installed without requiring a lot of excavation, especially on unsteady or wet ground. Determining which type of foundation best meets your needs will depend on your soil conditions and project requirements, as well as your desire for cost-effectiveness and long-term structural integrity.

Advantages and disadvantages

Strip bases have several benefits, such as:

• Durability, reliability, high performance.
• Resistance to external loads. The tape is able to withstand pressures significantly exceeding the weight of the building.
• Ability to build on most types of soil.
• Ease of construction, relatively low proportion of earthworks.
• The amount of material compares favorably with some other types of foundation.
• Possibility of construction at any time of the year.
• The presence of many design options or materials used allows you to choose the best option for the existing conditions.
• The service life of the tape is long; with proper construction and proper care, it exceeds the service life of the building itself.

Additionally, there are drawbacks:

• There is a certain dependence on the hydrogeological conditions of the site.
• Despite the tape"s greater resistance to pressure loads, it does not respond well to axial tensile forces. If pressure appears at one point, cracks may form or the base may fracture.
• The self-weight of the base is quite large, which must be taken into account when performing calculations.
• There is a dependence on the load-bearing properties of the soil.

The strip foundation is the best choice out of all of them, even with a few drawbacks.

Kinds

Tape bases come in various varieties.

It is common to differentiate between the following based on the type of construction:

• Monolithic. It is a one-piece concrete casting with a reinforcement cage installed inside.
• Made. It is built from separate parts – foundation blocks, bricks, etc.P. Benefits in terms of construction time, but has slightly reduced resistance to loads, so it is used only in suitable conditions.

Tape bases come in different varieties based on depth:

• Non-buried. Built directly on the surface, used extremely rarely due to the inaccessibility of appropriate conditions.
• Shallow. Immerses to a relatively shallow depth, not reaching the winter freezing level. Allows for greater savings in material and labor, but requires suitable hydrogeological conditions.
• Recessed. The main type of strip base, immersed in the soil below the freezing depth. Has maximum resistance to loads, capable of supporting large massive buildings. Requires a lot of labor and a maximum amount of materials.

Additionally, combined strip foundations exist that are structurally combined with other foundation types, such as pile-strip, strip-column, etc.

What conditions is it suitable for?

Most construction sites can benefit from the use of strip foundations due to their versatility.

Principal limitations

• Availability of high standing groundwater.
• Weak bearing capacity of the soil.
• Complex soil composition, alternating dense and loose layers.

Furthermore, the existence of seasonal ground movements or t.n. frost heaving is a significant factor. It typically shows up on clay soils with moisture retention. The base is pushed outward when the water freezes and expands during the winter.

These forces are not uniform, which negatively affects the tape and leads to cracks. In addition, the tape does not react negatively to low temperatures and performs superbly on dry soils.

What is a pile foundation

A system of vertical supports submerged in the earth until they come into contact with dense layers is known as a pile foundation. The site’s geological conditions are the only factor that affects immersion depth, which can vary.

In the corners and other locations where forces are concentrated in the center of the future building, piles are placed in a specific order beneath the most heavily loaded sections. The building’s weight is distributed equally across all of the supports thanks to the calculation of the pile field.

After installation, the upper portions of the piles are cut or extended to create a flat plane, at which point a grillage—a horizontal strapping belt—is constructed. It joins the tops of the supports, distributes the loads over the whole area, and condenses the loads into a single system.

The grillage serves as the foundation for the zero overlap, which is where the building of the actual house starts. It is manufactured in a manner similar to that of a strip foundation, with the primary distinction being in the support’s point placement.

Pros and cons

The following are some benefits of pile foundations:

• High bearing capacity.
• Possibility of construction on problematic soils.
• Weak influence of the hydrogeological situation on the stability of the foundation.
• No need for site preparation, the possibility of working on slopes or folds of the relief.
• Virtually no excavation required.

Negative aspects of a pile foundation

• Difficulty or impossibility of arranging basements.
• Installation of piles requires the use of special equipment, which increases the cost and complicates the work.
• It is impossible to calculate the immersion depth of each support with great accuracy.

Due to their specificity in working on damp, swampy soils, pile foundations are preferred in many areas with high groundwater levels. The issues of soil instability are entirely resolved by installing a pile foundation by qualified experts, which creates a sturdy and dependable foundation.

Varieties

The term "pile foundation" refers to a broad category of foundation types. Their methods of immersion in the ground and the kind of supports they use are different.

Existence

• Driven piles. Ready-made reinforced concrete rods are used, which are driven into the ground using special construction machines. They are considered the most powerful and reliable option, but the immersion method significantly limits the possibility of working near finished buildings.
• Bored. These piles are practically manufactured on site. Concrete is poured into the prepared well, forming a vertical support rod. Bored piles can be created by hand, and the blunt end of the rod increases the strength of the installation and reduces the possibility of settlement.
• Screw. This type of base has been actively used relatively recently. The advantage of screw piles is the ability to install manually; work can be carried out in close proximity to previously constructed buildings. The pile is a metal pipe with a pointed end, at a short distance from which several blades are welded. They act like cutting a screw. The pile is screwed into the ground to the required depth using a lever. Can be removed and reused if necessary.

Under what conditions should it be used?

Loose, loose, or wet soil conditions are ideal for the operation of pile foundations. One could argue that all that matters to them is the presence of dense layers, and nothing else. In wetlands and other areas with loose and unstable soils, piles are the best—and frequently the only—solution in this regard.

The choices for using pile foundations are determined by the capacity to transfer loads to great depths while avoiding shaky and loose surface layers.

Pile supports differ from most other types of foundation because they have shown to be effective in regions with fluctuating temperatures.

Which is better?

Claiming the superiority of one kind of foundation over another without mentioning particular circumstances is absurd. There are two separate ways to construct support structures that completely guarantee the building’s stability and dependability: pile foundations and strip foundations.

The choice of one type over another is influenced by a number of factors, including the site’s hydrogeological conditions, the relief type, and seasonal variations in groundwater levels. A determination is made regarding the relative benefits of each option based on the combination of these factors.

Which type is built faster??

The rate at which foundations are built is a unique indicator that depends on numerous variables. If the concrete’s hardening time is the deciding factor for strip foundations, then the availability of equipment, the intricacy and consistency of the soil layer distribution, the depth of dense layers, etc., all affect working with piles.

It is therefore difficult and incorrect to debate which type of construction is faster than the other. The sole distinction is seasonality; it is illogical or impossible to submerge piles in frozen soil during the winter.

Additionally, there is typically year-round work available with strip foundations, which boosts construction productivity.

Types of soils – for which soils which foundation is best suited

Strip foundations function best in dry, dense soils with little aquifer depth and no frost heaving. A pile foundation is the best option for work on loose or loose soils that are saturated with water.

Strip foundations are also far more versatile than pile types because they can support relatively large external loads and are more universally supported.

Because it is impossible to build a basement and use the house’s basement, pile foundations should not be used where strip types can be used.

Useful video

Discover which type of foundation is preferable in this video: pile or strip:

Before making a choice, it is important to carefully consider a number of important factors that affect strip and screw pile foundations.

Known for their extensive use in building, strip foundations offer a strong base by distributing the weight of the structure over a larger area. This kind of foundation works well for structures on stable ground that can be excavated to a significant depth. It is frequently chosen for larger structures where the distribution of weight is crucial because it provides good stability.

Conversely, screw pile foundations are becoming more and more common because of their effectiveness and low installation disturbance. They are especially useful in places with bad soil, where traditional foundations might need to be reinforced or excavated extensively. Screw piles are fastened into the ground by screwing them in, which shortens the construction period and provides instant load-bearing capacity.

The unique conditions of the site are important consideration when choosing between these two types. It is necessary to carefully consider factors like soil type, load-bearing requirements, environmental impact, and budgetary constraints. It is imperative to seek advice from a qualified engineer or architect in order to determine the type of foundation that will best meet the needs of your project and guarantee structural integrity over time.

Video on the topic

We count the savings. Screw piles VS strip foundation