The choice of the type of foundation and building materials for the construction of a house is a decisive factor in its solidity, safety, long-term and all-season operation. A frame house on stilts, contrary to popular belief, despite the relatively low cost of such a structure, is characterized by a high degree of stability during construction, even on weak soils, of course, provided that technological standards are met and if specialists have certain experience and skills.
Advantages and disadvantages
Frame houses on stilts have both positive and negative sides. Let's start with the pros.
Security. The pile foundation thoroughly fixes the soil, guaranteeing the inviolability of the foundation on water-saturated and weak soils.
Strength. The pile foundation, in contrast to the concrete one, is not afraid of the lowered temperature, it does not crack when it fluctuates.
Efficiency of installation. The installation of supports for a house of 6 × 8 meters, together with markings and strapping, takes 1-2 days.
Long service time. Zinc coated piles are resistant to rust. A frame house on a pile structure will last 70 years and will not require foundation repair.
This is an inexpensive base option. in comparison with other types of foundations.
A big plus is the ability to build it yourself. For our country and mentality, where everyone wants to participate in the construction of their own home, this is a priority task. Moreover, this makes it possible to save a lot on employee wages.
There are also disadvantages
Poor thermal insulation. Foundations based on piles buried in the ground require additional insulation.
Metal piles are susceptible to rust formation. Due to electrochemical corrosion, steel oxidizes and quickly degrades. The problem is solved by the use of anticorrosive spraying.
Specificity of structural elements. When building houses on stilts, it is impossible to plan a basement or a zero level. To expand the usable space, frame frames are often erected with an attic or full-scale second floor.
Building a house on stilts according to the design solution is:
- saving on building materials;
- saving time;
- control at all stages of work, insurance against possible mistakes.
But the main thing is that the project is a document that allows you to obtain permission for construction work, to legalize the structure, has the property of an official document when accepting construction work.
Individual designs are not always acceptable due to cost reasons. As a result, typical design solutions are in high demand.
The choice is made according to a number of parameters:
- type of object;
- material (wall construction);
- number of storeys.
So, there are different options for projects of frame houses on stilts: from small inexpensive ones to houses for a large family. Most often they are one-story.
Residential buildings can be chosen with an attic floor, a veranda, a balcony, a garage, possibly with a second light, a pool or a sauna.
Types of piles
The key purpose of the piles is to take on the volume of weight from the structure and transmit it to the soil. They are long rods of different materials that are mounted in the ground.
In conjunction with the soil, the piles are divided into racks, which direct the load onto the rocky soil directly, or hanging samples, which can disperse the weight of the structure.
According to the immersion technology, piles are also divided into several types
Hammered - a particularly well-established technology and the most common in the Russian Federation. This can also include driving piles with the use of leader drilling technology. These piles are driven into the ground using specialized equipment - pneumatic hammers. The first step is to calculate the level of immersion of the pile-rack, impact power and time consumption. Then it is placed vertically to the ground and penetrates deep into the soil with blows
Driving poles, produced at the enterprise or at the construction site and mounted in the ground, are installed using a technology similar to that of rammed posts. The difference is that the well is filled with concrete solution in parallel with its creation. After the recess is filled, a reinforcing bar frame is placed in it. The main advantage of these piles is their high production speed
Submersible by screwing are distinguished by the type of tip (welded and cast) and by individual design features for use on various soils
Bored, arranged directly in the soil in a pre-made well, are created by drilling a deep well in the required place, installing a frame made of reinforcing bars into it and further filling the resulting structure with a concrete solution
Vibrating - using the peculiarity of the soil to change their own structure when exposed to vibration. This method combines shock, vibration and indentation technology. The pile is simultaneously influenced by 3 forces
Pressed - a method developed for the installation of piles near functioning objects. This eliminates the vibration impact on their foundations. Practiced in places where earth shaking can break the solidity of the foundations of other structures. The method of installing such piles involves the technology of pressing into the ground by means of specialized equipment, while the effect of mechanical vibrations on the ground is smoothed out
Depending on the materials of execution, piles are:
- w \ b;
According to the configuration of the section and design, piles are:
- with and without broadening;
- multi-piece and solid;
- w \ b prismatic type;
- solid section;
- piles of columns.
The use of any pile format is selected according to the soil and project documentation.
They are mostly rectangular and square. In addition, sometimes there is a cylindrical cavity inside them. Their key difference is that the length of a monolithic pile is unchanged.
This type of piles is distinguished by the ability to assemble one long pile from several small piles. They are block reinforced concrete elements that dock together.
The ability to withstand the load is greatly influenced by characteristics such as the footage of the piles, the diameter of the body and blades. All this can be calculated based on the mass of the building, its dimensions, the number of floors, the type of materials for roofing, and so on.
For an average house of 150 m2, the specific gravity will be approximately 350 kg / m2. Each pile is designed for approximately 5 tons of load, therefore, for the implementation of this project, the approximate number is 20 pieces.
Construction of a pile foundation
A conventional screw-pile foundation for a frame is constructed according to a certain algorithm.
The locations of the piles are marked on the site. These are certainly the corners of the building, partitions and load-bearing walls.
Screwing in piles
The piles are screwed in either manually or by means of special equipment. At the same time, the perpendicularity of the entry of the pile into the soil and the depth should be kept under control.
Piles are certainly placed in areas where the building has the greatest load on the ground: at corners and at the intersection of load-bearing walls. When the distance between the posts exceeds 3 meters, then intermediate posts are placed in the middle.
The recommended pitch (maximum distance) for piles driven into the ground by screwing is 1.5-2.5 meters.
The main thing is not to align the posts by partially unscrewing them from the ground. This reduces the ability to withstand the load by several times. For horizontal alignment, the pile posts are simply filed.
Installation of heads
Steel platforms - heads are mounted on shortened piles by means of electric welding. They are practiced as a strapping support.
Before constructing the frame structure, it is required to complete the strapping. The bottom rail ties the individual piles into a coherent system, proportionally distributing the load across the entire base, so it is important to choose the right material.
The grillage of piles of a frame house is usually made of coniferous wood (spruce, pine, cedar) with a moisture content of more than 20%, which is placed on the head on the edge, and is also sewn together.
coniferous trees are characterized by high resin content, which reduces the risk of decay, increases moisture resistance;
- this material is less deformed, does not crack;
- costs less than other lumber.
Consider the types of strapping materials
Bar. When tying the base of a house, a beam of 150 × 150 and 100 × 150 mm is usually practiced.
Two massive boards with a piece of timber. The beam is arranged between 2 boards to form a kind of recess for the walls
The bottom strapping of the base is made of hammered boards. When strapping is carried out, the boards are placed on the edge
One solid board is rarely practiced. Exclusively for lightweight one-story and non-residential buildings. The main thing is that good quality materials are used
In the construction business, specific requirements and standards are imposed on everything, and the strapping is no exception.
To ensure the safety of the inhabitants of the house and prevent the destruction of the structure ahead of time, it is necessary that this component precisely meets certain conditions
- For the bottom strapping, an exclusively new, high-quality and straight bar is used. All structural parts must be of the same size when they are boards. Their size is 38 × 140 or 38 × 100 mm, and when it is a timber, its size is 120 × 120 or 150 × 150 mm;
- For such tasks, it is recommended to use coniferous woods (the above are the reasons).
- All wood materials should be prepared in advance so that their operating time is extremely long. Preparation includes processing wood with compounds that prevent decay, the appearance of insects, protects the material from dampness, and so on.
House piles must be extremely strong.
- The trunk used for the grillage must be straight. This is important when erecting a frame.
- It should be checked that the harness exactly follows the outline of the constructed base. Otherwise, cavities appear where moisture collects, and this contributes to the premature decay of wood.
House building technology
The basis of the building is a load-bearing timber frame, on which the cladding is installed. For frame-panel construction technology, a wall material manufactured at the factory is used. These are assembled panels with an intermediate layer of thermal insulation material between 2 OSB boards. Frame-panel technology assumes the use of elements, when the wall cladding is carried out simultaneously with their thermal insulation.
Let's consider step by step the key phases of construction
The construction of a frame on screw piles begins with the construction of the foundation for the future structure. The maximum load of one rod reaches 5 tons, which guarantees the ability of the structure to withstand the forces trying to bring it out of its original state, even when the soil is structurally unstable.
Strapping the base of the house. The first step is to install the lower strapping - along the outline of the base, a bar with a section of 150 × 150 mm or 200 × 200 mm is installed. All parts are treated with an antiseptic
Assembling the structural base of the frame. Vertical racks are installed in the corners of the base, they are tied by means of a bar, then intermediate racks are placed. Another way is the installation of the transverse lathing of the walls and the parallel installation of ready-made frame parts
Fastening the upper harness. A bar of the same section and of the same material as for the lower one is fixed at the top of the frame. The walls are reinforced with diagonal stiffeners. This provides spatial shear stiffness in the lateral plane
Wall cladding. Install structures that enclose the openings of doors and windows. The skeleton is revetted with factory panels or the panel cladding method is used
Overlapping device between the residential floor and the attic. On the upper end of the walls, on the long sides of the house, a beam of 100 × 100 mm or 150 × 150 mm (Mauerlat) is placed. It takes the load from the rafter system and distributes it proportionally along the load-bearing walls
Installation of roof structures, laying of roofing material. For houses made of wood on piles, as a rule, gable roofs with a slope of 35-45 degrees are designed. When the slope is greater, the wind pressure increases, less - the snow remains on the roof, and this is an unnecessary load
Upon completion of key activities, doors and windows are installed, floor insulation and floors between the residential floor and the attic are insulated, engineering support networks are brought in and installed. The facade is finished with a facing composite material, lining, block house, siding. The final phase is thermal insulation and finishing of the basement, installation of a blind area. Frameworks do not shrink, therefore, internal finishing work can not be delayed.