When starting to build a house, most people understand that you need to start with the foundation. How to properly fill the foundation under the house, not everyone knows. We will try to consider the whole complex of construction works and activities that are included in this process.
Very often, most people who have land plots, sooner or later, are going to build them up. Two positions take the lead in development: a toilet (at least temporarily - for the duration of construction) and a house. If everything is clear with the first position - no special skills are required there, then the second one requires very careful consideration and calculation.
So - how to fill the foundation under the house? Consider the most common type of foundation - tape, seamless, monolithic. It is widely used in construction, for a number of reasons:
- with a heavy load of the structure on the foundation
- eliminates the destruction of the structure, during subsidence of the soil, in some areas.
The initial stage - marking the foundation for the house
Before starting work, it is necessary to make an accurate markup. The marking is made along the axes of the building (the middle of the walls). And already from the axis of the building, the width of the foundation is measured. Usually, the foundation is poured 5-15 cm wider than the walls, it all depends on the design of the building.
After marking is completed, with the help of a nylon cord and pegs driven into the corners of the border of the future foundation, a trench is marked.
Soil sampling under the trench
You need to dig below the freezing depth by 20 - 40 cm. The freezing depth for a particular area can be found on the Internet or ask the old-timers.
If construction is carried out on heaving soils, then the depth of the foundation increases by 60-100 cm. This volume is filled with river sand, followed by tamping (each layer 15-25 cm) or pouring water. This action is necessary in order for the sand to gain density.
There are two ways to dig a trench under the foundation of a house:
- manual
- mechanical.
The manual method is relevant if the volume of the foundation is small and you have many relatives (just kidding). The second method involves the use of construction equipment - an excavator, with the required bucket volume.
The selection of soil for the foundation of the house, using an excavator, is ideal for large volumes. If it is not planned to dig a pit, inside which a strip foundation will be poured, then you can hire a JCB tractor excavator (in common 3 in 1). This excavator will not only dig a trench for the foundation, but also plan or store the selected soil using a bulldozer blade.
When the trench under the foundation of the house is dug, it's time to mark the laying of the sleeve - pipes. The sleeve serves to enter communications into the house - water, sewerage. Sleeves are laid at a depth below the freezing of the soil, but must be in the body of concrete. The diameter of the sleeve is selected slightly larger than the diameter of the communication pipe. For the duration of the work, it is better to drown them out on both sides - for example, plug them with rags.
The time period for laying the sleeve can be any, in the process, from the installation of the formwork to the installation of the reinforcement cage. But before pouring concrete.
Foundation formwork
The next stage of work is the installation of formwork. The formwork is made of moisture-resistant plywood or boards. The use of formwork allows you to pour the foundation for the house brought to a single level (even if the site allotted for construction is located on uneven terrain) and prevent too much moisture intake from the poured concrete. The formwork also protects the poured concrete from falling into it, crumbling soil.
Shuttering panels are knocked together or sawn to such a size that they can be moved and mounted by two people. The height of the formwork board should be 5-10 cm higher than the level of the poured concrete.
When installing shields in a trench, vertical posts are used, which serve to strengthen the shield and make it possible to install horizontal screeds.
Racks are nailed to the shields with nails or screwed with self-tapping screws. You can rent ready-made shields that are fastened together with special locks.
Armoframe
The next stage of pouring the foundation is the manufacture of the reinforcement cage. The reinforced frame is made of reinforcement of various diameters and serves as the internal skeleton of the foundation. For residential, low-rise construction, relief reinforcement Ø 10-12-14 mm and smooth reinforcement Ø 8-10 mm are used.
The geometric section of the armoframe is made of two types - square or rectangular. The dimensions of the reinforcement cage are calculated in such a way that it is in the body of concrete, with a protective layer of 3-5 cm, around the entire perimeter.
The technology of the reinforcement cage is standard - with the help of a knitting wire, a frame is knitted, where the corrugated reinforcement is located horizontally (for better adhesion to concrete), and the smooth reinforcement is vertical, forming cells of a square or rectangular shape.
The first and second meshes of the reinforcing cage are interconnected by vertical rods (made from pieces of reinforcement of the required length) or U-shaped mortgages (made from reinforcement, shelf dimensions according to the project).
For the production of work on the manufacture of all units of the reinforcement cage, it is recommended to use knitting wire, and not spot welding!
Armoframe can be made in two ways:
- inside the trench - if construction equipment is not used. With this method, only the inner or outer sides of the formwork are mounted. When the reinforcement cage is connected, the formwork closes completely. This method is relevant if the installation of the strip foundation is carried out inside the pit.
- production of a reinforcement cage outside the formwork. The reinforcing cage is knitted at the construction site, then mounted inside the formwork using a truck crane. This method is used when the trench is open.
Finishing stage - pouring the foundation of the house
After the installation of the reinforcement cage, the formwork is unfastened. The formwork is fastened with vertically located rods - bars, which are simply nailed to both sides of the formwork boards. The lower board is fixed with the help of racks - supports (beams, racks - jacks), with reliable fixation, completely eliminating the mobility of the formwork.
The formwork is unfastened, the reinforcement frame is mounted - we proceed to pouring concrete. For the foundation of a residential building, it is best to order concrete produced at a special plant of the desired brand. The brand of concrete is indicated in the project or calculated separately.
With a small volume, concrete is poured directly from mixer machines.
If the volume of poured concrete is large, it is better to use a concrete pump installed on construction equipment. When pouring concrete foundation under the house, it is imperative to compact it with the help of electric vibrators, the mace of which must reach the bottom of the trench.
The foundation of the tape type is poured at a time, without technological interruptions. If pouring is carried out in the cold season (up to -5C), special additives are added to the concrete to prevent it from freezing.
Curing
Care for the poured foundation under the house is carried out as follows:<гд>
- cover with waterproof material (e.g. polyethylene)
- in hot weather, spill with water (2-6 times a day)
Construction proverb - concrete loves moisture! When drying, cracking is possible (up to through). Repair of a cracked foundation will require significant financial costs - up to the dismantling of part of the foundation, followed by pouring.
Concluding the article, it is worth noting that the foundation of the house, made according to all building rules, guarantees the integrity of the building - for this reason, you cannot save on it!
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