Building a foundation

Types and cost of pouring foundations

Choosing the foundation for your home
When choosing the type of foundation, the following factors should be considered:

• The slope of the site;
• The nature and type of soil on which the house is planned to be built. To determine the type, it is necessary to obtain the results of geological research on the site;
• The depth of soil freezing. It can be obtained after a complete investigation;
• The technical characteristics of the structure that will be erected on the site;
• The level of groundwater.

The most popular types of house foundation are:

1. Strip foundation;
   • Shallow-depth. It is used for lightweight frame houses, where the depth of laying is not more than 600mm.
   • Strip-pile foundation. It is mainly used on weak and marshy soils. Its feature is that the walls of the building rest on a shallow-depth strip foundation, and the strip rests on piles that are deeper than the freezing level.
2. Slab foundation
3. Pile foundation

Foundation Calculation
For the correct calculation, we need to determine several basic parameters:

Calculation of the depth of foundation laying.
To obtain data for these calculations, we need to know the technical characteristics of the structure, according to which we select a suitable type. Then we need to find out the characteristics of the soil, according to which we obtain the level of soil freezing.
It is also important to know the level of groundwater.

How to get parameters for calculating the depth of foundation laying?

• Characteristics can be obtained based on geological research of the site. After this parameter becomes known, we can determine the depth of soil freezing.
• The level of groundwater can be determined independently by digging a well measuring 1 * 1 m with a depth of 2-3 meters. After a few days, the well will be filled with water, and you can monitor the level of groundwater.

Preparatory work
Before starting construction, the following preparatory work must be carried out:

• Excavate a pit or prepare a trench
• Prepare the soleplate

Our soleplate consists of 20 cm of sand with a vibratory tamper, followed by a geotextile layer to prevent gravel from mixing with sand, and then 20 cm of gravel. After that, a 50 mm thick subconcrete is poured, on which a waterproofing layer in 2 layers is laid. Insulation foam is laid on top of it.

Formwork installation
Formwork is a structure made of boards, planks, struts, and supports designed to give concrete and reinforced concrete structures the correct shape. The simplest material used for formwork is boards. Sheets are made from boards, which are connected into a single complex to hold the concrete and give it the correct shape.

You can also always rent specialized small or large sheet formwork, which comes complete with all the fasteners and is assembled simply like a construction set. A level and builder’s level are used for installation. If the supports are installed incorrectly, the formwork may break, resulting in additional concrete costs and expenses.

Foundation reinforcement
Reinforcement is necessary so that concrete works well under compression, and metal under bending. Reinforced concrete was invented for the strength of the structure, which works well both under compression and under bending.

It is precisely because of the heterogeneity of the soil, frost heave, that it is very difficult to build a building, and reinforcement allows you to resist this.

For concrete reinforcement, steel reinforcement with a diameter of 8,10,12 mm, or a composite material made of fiberglass can be used. Each material has its own advantages and disadvantages.

Reinforcement is installed on plastic fasteners that provide the necessary 40 mm protective layer of concrete for our frame.

Reinforcement consists of several longitudinal and transverse elements.

Longitudinal reinforcement

It resists tension. Here, reinforcement of length 6 or 11.7 m is usually used. The laying scheme depends on:

• Calculation of the required area of the cross-sectional area of the reinforcement;
• Accounting for all loads on the support (own weight, snow, and wind);
• The bearing capacity of the soil according to geological surveys;

Transverse reinforcement
It is necessary to hold our structure in a working position and also prevents the development of cracks. We use P-shaped and S-shaped elements.

Common mistakes when building a foundation
Very often, many make typical mistakes such as:

• The wrong choice of material. This can lead to cracks on the walls and the destruction of the building;
• The wrong calculation of the depth of laying can lead to the fact that the frost heaving of the soil will begin to raise and lower part of the structure, which will lead to the appearance of cracks;
• Improper laying or choice of waterproofing can lead to flooding of basements and rapid wear;
• An improperly made backfill can also lead to improper functioning of the foundation of the house.

For more details on mistakes, you can check the section — Common Mistakes.

Frequently Asked Questions

Question: What kind of foundation do you recommend building?

Answer: Everyone has their own strengths and weaknesses, but there is one main rule: there must be good access to utilities.

Question: I want to build a shallow strip foundation, what advice can you give me?

Answer: We recommend insulating the formwork and cutting off the cold front from the building. This is done to prevent heaving.

Question: Do I need to pour sand under the foundation, and how much?

Answer: Yes, it is recommended to pour 20cm of sand and 20cm of gravel, this is the optimal amount of building material.