Before starting construction work, many previously calculate the required amount of material. This is the right approach to such a serious matter. But at this stage, many questions arise. One of them: what sand is needed for the foundation?
The selection of such material should be given special attention, since this is an important component, one of the main components used in the manufacture of concrete. The durability of the foundation, the future foundation of the house, will depend on the quality of the mixture obtained. The modern market offers a huge assortment of sand, both natural and artificial. How to make a choice so that the foundation does not suffer from it, the article will tell.
Sand Selection Basics
Even a person ignorant of construction issues will be able to guess that exceptionally clean sand is suitable for the foundation. Initially, various organic elements may be present in it: small twigs, grass, and more. Such material is not suitable for construction work, so there must be sown sand, cleaned from extraneous debris.
However, a simple pouring can not be dispensed with when it comes to such impurities as lime or clay. To clean such sand is much more difficult, so when buying building materials you need to pay attention to it right away. The clay content in the sand is not more than five percent of the total mass, especially if a solution is made for the foundation. Otherwise, the structure after some time will shrink, crack and will not be particularly reliable.
Sand Purity Check
Before choosing which sand is needed for the foundation, you should check its cleanliness. For this, they usually use a simple method. You will need any empty transparent bottle (glass or plastic). Sand is poured into it by one third and half filled with water. Then shake the bottle vigorously so that the components mix well with each other. After that, they put her and wait five to ten minutes. If the water in the bottle became muddy and dirty, then such sand is not suitable for the foundation. If a foreign substance has appeared on the surface, the layer of which exceeds half a centimeter, then such material should also not be taken.
Now consider what kind of sand exists .
Types of sand for the embankment under the base
To ensure the reliability of the structure under construction, according to the norms of SNiP, it is necessary to use bulk mixtures. The market sells sedimentary rocks in three forms, depending on where they were mined. This is sand:
To answer the question which of them is most suitable for a foundation pillow, it is worth familiarizing yourself with the characteristics and nuances of using each type.
Quarry sand
This raw material is mined in quarries, breaking rocks. An important indicator of the reliability and strength of quarry sand is its moisture parameter. A ratio of one to five percent is considered acceptable. Suitable humidity can be determined visually. From the sand it will not work to form a dense lump - it simply crumbles.
Quarry construction sand is considered the cheapest material. The price for it ranges from three hundred to seven hundred rubles per cubic meter. This is due to its low quality due to the large number of clay impurities and other substances. Nevertheless, these raw materials are in considerable demand.
Types of quarry sand
Depending on the type of processing, quartz raw materials are classified as follows.
1. Sandy soil. This is a crude mixture with various impurities. As a rule, summer cottages are leveled with it and trenches are bombarded.
2. Washed sand. Extracted from flooded deposits using hydromechanical equipment. The technology allows you to collect the mixture without any impurities and unnecessary components. This material is used in the manufacture of roads, paving slabs, concrete, brick and reinforced concrete products.
3. Sown sand. It is cleaned technically and mechanically from large particles and stones. Typically, such raw materials are used to prepare a mass of plaster, masonry mortars, and in casting stone products.
River sand
This raw material is extracted from the bottom of freshwater rivers. It rarely contains organic compounds and impurities. Therefore, river sand is considered a pure and natural product that is designed for multi-purpose use. It is an ideal material for laying the foundation, creating drains and diluting the solutions necessary for the interior decoration of the house. Due to natural polishing, river sand has an ideally smooth shape and a fine fraction within two millimeters.
Due to all these advantages, this material becomes universal and desirable, but rather expensive raw material for the foundation. So, the price of building sand extracted from the river can vary from seven hundred to one thousand rubles per cubic meter.
River sand classification
Raw materials from the bottom of the river can be very different from each other. Therefore, you should deal with a variety of grains of sand. They can be of several fractions: from 0.7 to 5 millimeters. A small sand grain embankment shrinks and compacts heavily, so it is only suitable for lightweight buildings. The following types of bulk river material are also distinguished.
1. Coarse sand. These are pebbles about five millimeters in size. They are obtained by cracking rocks with the help of special crushing and grinding equipment.
2. Coarse sand. It has an unobtrusive neutral color, mined in dry rivers. Ideal for decorating and decorating the room.
3. Washed river sand. These are medium sized grains. They have a gray or yellow color, since they include iron and silicon oxides.
Positive aspects of river sand
River sedimentary rocks have several positive qualities that are of great importance for the construction of the foundation. They meet technical and aesthetic requirements, do not rot and are not exposed to aggressive environments. River sand is characterized by high moisture resistance and excellent sound insulation. It is also a safe and environmentally friendly material.
For the construction of multi-storey buildings, only the large-fraction type is used, and for small houses, the average crumb is suitable. Also, river sand is ideal for landscaping sites, playgrounds, landscaping and decorating rooms.
Sea sand
Sea crumb is also exactly the material that is needed for the foundation. Sand is initially no better than river, and sometimes worse. This is due to the presence of organic impurities (algae, shells) and foreign objects. But sea sand must be cleaned of outsiders and washed, so it is considered clean and of high quality. Due to this, this material is the most expensive, and not everyone is willing to pay for it. It is more appropriate to use marine chips for construction where it is sold nearby and costs less.
Sand fractions
Any sand can be classified by its size. Specialists distinguish the following varieties of fractions.
- Very thin. These are grains of sand about 0.7 millimeters in size. They are suitable for the arrangement of playgrounds and unsuitable for construction.
- Thin. Grains in size reach from 0.7 to 1.0 millimeters. This is loose material. You can’t use such sand for construction, but it will be good for preparing lean concrete.
- Fine fraction. It is a grain size of 1.5-2.0 mm. When using it, the consumption of cement mixture increases.
- Medium. Grains (2.0-2.5 millimeters) can be used to create standard concrete.
- Large . Sand particles in size reach three millimeters. This fraction is ideal for breeding high-quality concrete mix, which will be used in large-scale construction.
- Very large. Particles are more than three millimeters in diameter. They are added to the foundation pillow and used to distribute the mass of the structure.
The choice of sand for the foundation
So what kind of sand is needed, river or quarry? Experts agree that the first option is most suitable for the construction of foundations. It will create a layer that will increase the strength, stability of the building, prevent “walking” and the formation of cracks.
However, river sand will not be affordable for everyone. In this case, it is allowed to use quarry chips, but always washed. A sand and gravel mixture is also suitable, which improves the quality of the composition for laying under the pillow.
Amount of sand needed
Usually one part of cement is taken on five parts of sand. But this calculation is suitable if the solution is made only of these two components. The ratio of sand, gravel and cement to the foundation will be completely different. As a rule, they are taken in the following proportions: four parts of sand, two parts of crushed stone and one - cement.
As can be seen from the calculations, it is always necessary to take more sand than other components. The quantity of materials itself directly depends on the height of the pillow and the building itself. It is better to buy sand with a small margin so that you do not have to buy it at the wrong time. Residues can be adapted to prepare mortars for wall decoration or masonry.
Summarizing
Answering the question of what kind of sand is needed for the foundation, it should be noted that river grains of medium fraction are considered an ideal option. Such material has excellent properties for construction purposes. It allows you to build the most solid foundation, which will stand idle for a long time and will be an excellent foundation for construction.
It is necessary to purchase sand from reliable manufacturers, so as not to stumble on low-quality raw materials. It is recommended to check the material before buying for moisture levels and the amount of impurities. It is also worth paying attention to the conformity of the procurement size. As a rule, a cubic meter should be about one and a half tons of sand.