In the world, in almost every country you can find a house on stilts. In some parts of the world, houses have been built for centuries on wooden logs dug vertically into the ground. This technology allows you to build housing even on the water. In recent decades, no one has been surprised by a house on piles made of concrete. In modern construction, a real revolution has come after the use of screw piles for the construction of light buildings.
General information
A stilt house is an ideal solution to the problem of building where the soil does not fit under a monolithic strip foundation. It can be built on lots with the following features:
• with previously created terrain;
• with difficult terrain;
• with high soil moisture;
• where excavation is not possible;
• in areas with deep freezing levels.
Building houses on piles is very popular today, but metal supports are especially in demand, which make it possible to quickly build small buildings with your own hands. The advantages of such buildings are:
• saving time andconstruction cost;
• the possibility of working on problematic soils;
• no need for soil leveling;
• the possibility of erecting wooden structures on lawns, slopes, near trees;
• high piles protect the house from penetration of rodents;
• during floods, the dwelling is protected from possible flooding;
• The use of high piles makes it possible to use the area located under the house for parking a car, a summer kitchen or a sports ground.
House on wooden stilts
Despite modern advances in construction, some of the old ways of building buildings are successfully used to this day. A house on stilts made of wood is a typical construction method popular in many states. So in Russia, for many centuries, wooden houses were built on logs from wood. They were often called "chairs". For such piles, the trunks of those tree species that are characterized by a long service life are used. These include pine, oak, larch. The minimum diameter of such "chairs" to create a reliable foundation is 20 cm. The larger it is, the better. To lengthen the service life of wooden piles, they are subjected to fire treatment - they are burned. In the ground, scorched wood is difficult to rot, which makes it possible to erect buildings whose service life is many tens of years (at least 30 years). To date, the treatment of piles with fire is often replaced by impregnation with special antiseptics orcoating with bitumen.
Because there are enough high-tech piles made of metal available for sale today, building houses with logs is receding into the background. Most often they are used for country frame or wooden structures.
The stilt house pictured above would require digging pretty deep holes for the logs. The minimum depth for digging in wooden piles is 1.25 m. They must rest against bars with a section of 10x20 cm and a length of 40-50 cm. Wooden piles are located in all corners of the building and are located along its perimeter (with a distance of 1-2 m). The pits are backfilled in layers of 20 cm. Each of them is carefully rammed. The upper 30-40 cm backfill is made using fine crushed granite or gravel.
Disadvantages of wooden piles
Despite their popularity, wooden piles have been losing ground in recent years. This is due to the following factors:
• the difficulty of digging in logs;
• the need for additional wood processing;
• short pile life compared to other products of this type;
• the introduction of more high-tech building materials;
• high price for quality wood.
Pile-screw foundation
Foundations built using screw piles have been used for the construction of military facilities for a long time. This specialization is due to the fact that their design allowsbuild reliable supports for a variety of buildings in the shortest possible time. Abroad, the modern technology of building buildings on pile foundations was mastered decades ago. It is used for the construction of residential buildings, outbuildings, as well as various industrial facilities.
In the Russian Federation, these foundations have long been used exclusively for the construction of light structures, since commercially available screw piles have a low bearing load. Recently, modern varieties of metal supports have appeared, which make it possible to make the scope of such building materials much wider.
Every year the foundation of a house on stilts is erected by an increasing number of Russians. This is due to the improvement in the quality of this building material and its affordable price. A house on screw piles, reviews of which most of its owners have only positive reviews, can become an adornment of any site. Most often it is a light structure made of wood. This type includes frame houses, and buildings made of other lightweight building materials. Screw piles are used for playgrounds, baths, saunas, fences, gazebos, greenhouses, terraces.
General information about screw piles
Screw piles under the house - the main element of the foundation. They are a steel pipe, the metal thickness of which is at least 4 mm. On the one hand, it has a sharp point. At this end of the pile is a cutting blade, with which the support is screwed into the ground. Many people thinkthat the use of such building materials will require the use of special equipment. In fact, the ideal shape of the blades of screw piles allows them to be screwed to the required depth by 3-4 workers.
For the construction of objects with differences in height or with the presence of various lateral loads, piles with two blades are used. This design gives the foundation additional reliability. The diameter of the blades of screw piles ranges from 200-850 mm. The supports themselves have a diameter of 50-350 mm. The length of screw piles can be 2-11 m. In addition to hollow piles, solid piles are also available.
Advantages of screw piles
Those who have already built a house on stilts leave mostly positive reviews about them. The main advantages of these building materials include:
• reusable due to easy disassembly without damage;
• no need for significant earthworks;
• the possibility of building houses on mobile and flooded areas;
• fast foundation;
• start construction of the building immediately after laying the foundation;
• the possibility of using for the construction of various extensions;
• long service life exceeding 100 years;
• acceptable cost, which is almost three times less than the price of a strip foundation;
• no construction debris on site;
• the possibility of replacing or repairing the foundation.
Due to the optimal perpendicular arrangement of the blades, the screw pile does not loosen it when screwed into the ground. The bearing capacity of such building materials ranges from 5-25 tons. For construction, piles with cast tips are chosen. The best protective coating of such supports is made on the basis of polyurethane resin. Very reliable galvanized piles, covered with protection from the outside and inside.
The cost of the foundation of screw supports depends on the size of the house. So, for example, a construction with an area of 6x6 m will cost 1-1.2 thousand dollars, and 9x12 m - 3-3.3 thousand.
Disadvantages of screw piles
Despite the fact that these building materials have few drawbacks, they still exist. Those who built a house on stilts leave mostly positive reviews about them. Among the most common shortcomings, most developers highlight:
• cannot be used on rocky or coarse soils;
• Deformation of the foundation, which is possible in case of a violation of the technology of the device. It occurs when, during the screwing of the piles, their position was not fixed, the strapping was performed incorrectly, the screws were hammered or installed in dug holes;
• ground subsidence resulting from poor site survey;
• corrosion of piles due to poor quality of anti-corrosion environment;
• the impossibility of building large houses using heavy building materials.
Variants of pile-screw projectsfoundations
There are several options for projects of such foundations. They are selected depending on the type of the future house and the soil on the site. The most common of foundation designs:
• single piles supporting individual building elements, used when a small extension is made to an existing building;
• standard foundation, which is built under the main elements of the building;
• pile tapes located under all walls of the house;
• pile field required when building a foundation for heavy structures.
Building a house on a pile-screw foundation
The house on screw piles is being built in several stages:
1. A building project is being created and the number of screws is calculated. Most often, piles with a diameter of 108 mm are chosen for frame and wooden houses. For small buildings, you can choose smaller screws, which will save money. When calculating the required number of piles, it should be remembered that with too often installed supports, the reliability of the foundation practically does not increase, but its cost increases significantly. One pile, after filling it with concrete, can withstand a load of 5-9 tons, so the distance between them during the construction of frame houses can be 3-5 m. The number of supports is increased when building two-story buildings or using heavier building materials. To increase the reliability of the pile-screw foundation, its bearing capacity is increased by 25-30%.
2. Producedsite marking and its preliminary preparation.
3. The type of foundation is chosen depending on the mass of the structure under construction, the type of soil and the depth of its freezing. Construction begins with a geodetic study of the soil. It is necessary to determine the location of groundwater and stable soil layers.
4. Piles are screwed into the ground according to the marks made. In this case, soil compaction occurs in the region of the screw, which contributes to strengthening the strength of the foundation. These works can be carried out in any weather. The pile is screwed in by at least 3 workers: one monitors the level of the support, and the other two screw it in to the desired mark. The supports are cut at a single level and poured with concrete. It gets inside the pile pipe, which strengthens the pile and prevents metal corrosion. After the concrete hardens, they proceed to welding the metal head to the support.
5. It is necessary to tie the piles to evenly distribute the bearing load. Most often it is made from a channel. The upper part of such a foundation is called a grillage. It redistributes the load of load-bearing structural elements.
6. Insulation of the pile-screw foundation is not required, since it is of a ventilated type. Sometimes the grillage is insulated, but if the work is not done correctly, humidity may appear, which is reflected in the entire building. It is best to insulate the floor of the house to save heat in the house.
7. Frame or wooden houses are erected on a prepared pile foundation.
8. The basement of the foundation is made hinged.
Which house onstilt pick?
Weighing all the pros and cons of choosing one or another type of support, we can say with confidence that a modern pile-screw foundation has more advantages than a wooden one. It surpasses the latter not only in technical, but also in economic and labor-intensive indicators. At the same time, its durability is many times greater than the service life of log supports.
