A concrete block columnar foundation is a common option for creating a strong and dependable foundation for your house. Using this technique, a number of concrete block columns are made to support the structure above. It is prized for its robustness, affordability, and longevity.
Comprehending the intricacies involved in building a columnar foundation is imperative to guarantee project success. Gaining a strong foundation for your building requires understanding these subtleties, which range from appropriate planning and layout to the actual construction process. You will be guided through the necessary steps and things to remember by this article.
Knowing exactly how to work with concrete blocks for your foundation can make a big difference in the outcome, whether you’re doing a new build or renovation. Let’s examine what you need to know to build a columnar foundation correctly as we delve into the practical aspects of the project.
| Aspect | Details |
| Foundation Depth | The depth of the foundation depends on soil type and load-bearing requirements. Generally, it should be below the frost line to prevent freezing and heaving. |
| Block Type | Use high-strength concrete blocks designed for foundations. They should be durable and resistant to moisture. |
| Column Spacing | Spacing between columns should be determined based on the load they need to support and the design of the structure. Standard spacing is typically between 1.5 to 3 meters. |
| Footings | Each column must be placed on a properly sized footing to distribute the load evenly and provide stability. |
| Reinforcement | Reinforce columns with steel rebar to improve strength and durability. Ensure that the rebar is properly placed and tied. |
| Drainage | Ensure proper drainage around the foundation to prevent water accumulation and soil erosion, which can weaken the foundation. |
Features of using a support-column structure, pros and cons
Private construction is the primary use case for these structures. Such foundations have very little load-bearing capacity, which severely restricts their operational potential.
Small frame, panel, or wooden one-story buildings are permitted to be erected on concrete pillars provided that the soil is not too prone to heaving.
Dense soil means that the columnar foundation’s load-bearing capabilities are adequate for building complete structures made of wood or logs on such terrain.
A columnar foundation does not allow for the construction of a basement; therefore, you should select alternative ground plans if that is your preference.
For a columnar block foundation, an immersion depth of up to one meter is advised. Laying FBS blocks to a great depth is too labor-intensive; instead, equip the structure using asbestos-cement pipes filled with concrete if construction conditions require you to go deeper.
In the following circumstances, building a block base is not advised:
- Construction of a massive building, the walls of which will be made of brick or reinforced concrete products.
- On clay soils saturated with moisture.
- With moving soil, since the columnar base weakly resists horizontal loads.
- When the construction site has natural elevation differences exceeding one meter.
The supplies needed to build supporting pillars are numerous. The 20*20*40-sized blocks are the most visually appealing.
They are perfect for building frame structures on:
- the cost of production is insignificant;
- to carry out the activity, it is necessary to attract hired workers, since the process is not complicated, it does not require significant labor costs.
Though there are certain drawbacks to this construction option as well:
- performing additional insulation of the base is associated with considerable problems;
- it is almost impossible to organize the reduction of heat losses.
Types of blocks
The kind of filler used in concrete mixes determines the classification of blocks produced industrially. Products are made lighter by adding voids to them.
If these products are going to be used in the construction of a columnar foundation, you shouldn’t use any that contain fillers (like expanded clay, sawdust, or shell rock) or have more voids than 25% of the volume.
Concrete blocks fall into the following categories based on their intended use:
- FBS – has a parallelepiped shape, recommended for constructing poles that can support the weight of light buildings.
- The lower layer of the foundation is laid from cushion blocks, the cross-section of which looks like a trapezoid (due to the widening of the lower part, the supporting platform increases, enhancing the load-bearing capacity of the base).
Certain blocks are used in the construction of private homes; their dimensions are suitable for manual installation.
Not every lightweight product option can be applied to the building of a columnar foundation: Because wood concrete blocks can only support a maximum of 50 kg per square centimeter, they are not appropriate.
Expanded clay concrete actively absorbs moisture, so it’s important to keep a close eye on the waterproofing of supports when using it.
It is forbidden to install aerated concrete or its foam equivalents below ground. Therefore, a solid concrete "brick" measuring 20 by 20 by 40 centimeters is the ideal choice for foundation supports. These goods are arranged in square columns to connect the rows.
Selection by parameters
Considering the advice, you ought to buy solid FBS with the specified measurements; their 32 kg weight enables you to install the items on your own.
The product’s technical specifications are as follows:
- strength reaches 150 kg/cm2;
- geometric dimensions – 20*20*40 cm;
- the product is capable of absorbing moisture within 15% of its own volume;
- the frost resistance of the block allows for at least 15 freeze/thaw cycles;
- maximum thermal conductivity of the element – 1.16 W/mK.
One benefit of employing these products is the speed at which supports can be constructed; an adhesive composition or a standard sand-cement mixture is used for laying. The procedure doesn’t require specialized equipment to be carried out on its own.
To ensure stability and longevity, building a columnar foundation with concrete blocks requires an understanding of several important details. In order to support the structure above, this kind of foundation uses vertical columns, so it needs to be precisely placed with the right reinforcement in place to handle loads. The proper kind of concrete block selection, precise alignment and spacing, and the inclusion of sufficient support components like rebar are important considerations. Any building project benefits from having a strong and dependable foundation thanks to careful consideration of these subtleties.
Construction
Even if you lack specialized knowledge in this area, you can still plan the event of building a columnar foundation with concrete blocks on your own. The primary prerequisite is meticulous process adherence; no work should be rushed.
Calculation and plan
First, the number, position, and cross-section of the pillars that the structure’s base will rest upon must be determined.
If the soil’s bearing capacity is ignored, this cannot be accomplished. The parameters of soil resistance to loads are displayed in the table below:
The mass of the structure being built, which includes the weight of the walls with floors and the roof, must be determined after the initial value is obtained. It is imperative to consider the force exerted on the foundation by wind and snow accumulation on the roof. The table provides all the values needed for the calculation:
Snow or wind-generated load: standard indicators vary by domestic region. The specifics are provided in SNiP number 2.01.07-85.
To find the area of the necessary supports, divide the structure’s calculated mass by the value found in the first table. To determine each support’s cross-sectional indicator, just divide the result by the estimated number of pillars.
The supports must be spaced 1.5–2 meters apart, however it is preferable to lower this amount to a meter for problematic soils.
Marking
The building’s intended construction site is meticulously leveled and cleared of any debris. The top layer of soil must be removed down to a depth of 25–30 cm.
They then start delineating the territory:
- stakes are driven into the corners, as well as at the intersection points of the walls;
- a cord is pulled along them;
- determine the installation points of the supports;
- dig holes under them.
Land works
Concrete block supports need to have roomy pits in order for plastering and waterproofing to be completed after the structure is built. This will guarantee the stability of the supports.
When the supports are buried more than a meter below the surface, this advice becomes extremely pertinent. The holes have dimensions of 50*50 cm and a depth of 15–30 cm if the base is buried shallowly enough.
Pillow
When the holes are ready, you must fill them with a cushion of sand, add water, and then gently compact the sand. Occasionally, home craftsmen will place paving slabs on the bottom in place of this event.
Since these products cannot support heavy loads, this cannot be done. The tile will eventually crumble under the weight of the structure, leaving the support without a sturdy base.
Sole
A sole is positioned beneath the pillars in order to improve the strength indicator. The expanded reinforced concrete platform goes by this name. Ready-made concrete is poured into the structure after the formwork has been constructed and reinforced.
There are some subtleties to consider:
- The dimensions of the structure must be almost twice the cross-section of the support being erected.
- It is certainly necessary to perform waterproofing the sole.
- To provide protection of waterproofing from the sharp edges of crushed stone, a screed of a weak solution is laid under the formwork (except for the protection of waterproofing, it levels the plane of the pillow).
You can carry out drainage work in the bastards’ gravel if necessary.
Pillars
Building columns in accordance with this scheme is required:
- Put a pair of blocks on top of the pillow;
- apply a viscous solution to them;
- lay the following elements perpendicular to the previous layer.
Continue doing this until the necessary height is reached.
It is essential to use a plumb line to continuously check the pillar’s vertical alignment while laying. Every component of the foundation needs to be shown at a single height.
Waterproofing
You must plaster the entire surface of the column after smearing a solution across the joints to strengthen the supports. It is advised to surround the structure with waterproofing or apply mastic once the solution has solidified.
Once this is done, the recess needs to be filled with soil and tamped down layer by layer to strengthen it.
Grillage
In areas that are not favorable for soil movement, strengthening a block foundation is necessary because a columnar foundation cannot support horizontal loads.
Using a grillage to tie the posts is a tried-and-true solution. It’s either a wooden beam or a belt made of reinforced concrete.
Pickup
Excavation is the final step in building a foundation. The area between the grillage and the ground is shielded by this design. Simply dig a shallow trench and fill it with concrete; it’s not hard to do.
Errors in the construction of supports
The most frequent error made by do-it-yourself artisans when constructing a foundation consisting of concrete block pillars is the absence of a sole. Many people are attempting to lower the labor intensity of their work and the cost of design.
However, over time, pillars without a sole will undoubtedly start to bow. Furthermore, the expansion of the lower portion of the supports is something that not everyone notices, and each column must have its own procedure followed.
Installing a columnar foundation on unstable soil is also unacceptable. Then, regardless of whether the sole is present beneath each column, the constructed building will progressively start to sink.
The next mistake is to build these supports on clay. Such soil will start to push the columns due in the winter. Regardless of the technology used in their construction, supports will start to diverge.
Оольы расчета нагрузок на столѱы неправильно расбетает проблема. The effort also includes a lateral component that can move the support to the side.
FBS reviews on forums
Recapitulating the opinions of do-it-yourself artisans who took a chance on building a columnar foundation on their own, it should be highlighted that the primary drawback of this kind of construction is an uneven block siege.
As a result, the foundation fractures. Additionally, the vast majority of users report that this phenomenon still occurs to them in spite of the excellent technological process.
The vast majority of individuals who constructed block supports by hand advise sticking to FBS products. Its larger size makes it possible to lay it in less time, and the material is stronger overall than asbestos-cement pipes or bricks.
The procedure for erecting a columnar foundation for a residential frame building is a topic of active discussion in the forum. The forum is addressing the issue of what to do in the event that incorrect support installation causes the columnar base to tilt.
This page contains a wealth of significant and practical knowledge regarding columnar foundations.
Video on the topic of the article
Block-based columnar foundation that can be DIYed: in the video
For many construction projects, constructing a columnar foundation out of concrete blocks is a useful and effective solution. Because of its advantages—such as affordability and longevity—it is a well-liked material for many kinds of buildings. You can make sure that your foundation is strong and durable by paying attention to the finer details of your project and adhering to the proper procedures.
Every stage, from adequately preparing the site to installing each column with care, is essential to the foundation’s overall stability. The performance of the foundation can be greatly impacted by making sure you have the proper concrete mix, precise measurements, and enough curing time.
In the end, a solid columnar foundation will give your building a stable base, enhancing both its longevity and safety. Through comprehension and management of the subtleties inherent in this construction technique, you can ensure a dependable and prosperous conclusion for your building endeavor.
