Among other types of foundation, strip is the most common in private construction. Filling it does not require impressive financial costs and is not particularly difficult - it can be built by a novice builder, you just need to understand the features of the work.
Advantages and disadvantages
Like any building structure, a strip foundation has its own advantages and disadvantages, it performs well in some operating conditions and is completely inapplicable in others.
To avoid mistakes in the design and construction of buildings based on strip foundations, it is important to know all of its properties and features. So, the main advantages of the design include:
- low cost of raw materials and installation work due to its small size;
- simplicity and ease of installation, no need for complex technological equipment and special professional skills of workers;
- resistance to constant high loads, that is, suitability for private two- or three-story construction;
- compatibility with all modern wall construction technologies;
- high speed of pouring concrete, which can significantly reduce the construction time.
However, this type of foundation has several disadvantages, the most serious of which are:
- the need for a detailed analysis of the soil and carrying out rather complex design calculations in order to determine the geometric parameters of the future foundation;
- large mass of the structure, which in case of an error in the calculations will contribute to the "subsidence" of the building.
After analyzing all the pros and cons of the strip foundation, we can come to the conclusion that the optimal scope of its application is private construction on sufficiently strong, stable soils without a slope... In addition, this type of foundation can help out in a limited budget and with a tight deadline.
Varieties of strip foundations
The main criterion for the classification of strip foundations is their internal structure. Depending on it, designs are divided into three groups:
- Monolithic foundations. They consist of reinforcing rods pre-installed in trenches and fastened together, which are poured with concrete. This technology provides the greatest strength, reliability and durability of structures.
- National teams. They consist of ready-made reinforced concrete blocks of industrial production, connected with cement mortar. Due to the heterogeneous structure, they are subject to deformation and destruction at the joints if the building conditions are not observed. The main advantage of the prefabricated foundation is the speed and ease of installation.
- Others. As a rule, this group unites light strip foundations for non-residential premises, for example, brick-stone, sand, soil-cement.
Pile-tape structures are kept apart. They are usually carried out using a monolithic technology, but include, among other things, deep cast piles with a reinforcing cage to hold the foundation on unstable soils.
Materials and tools for work
The role of the main building materials used in the construction of the formwork, the installation of rods and the pouring of the strip foundation is played by:
- boards, including lighthouse, longitudinal and necessary for the manufacture of formwork panels;
- reinforcement rods with a diameter of at least 10 mm are selected in accordance with the design loads and the reinforcement pattern;
- wire, tension hooks and staples, which are used to hold the rods together;
- concrete mortar, the components of which are cement, sand and crushed stone (the proportions of the components are given in the table below).
The set of tools varies depending on the planned scope of work. If the perimeter and width of the foundation is relatively small, hand tools predominate, such as:
- shovels, shovels for excavation and pouring;
- metal containers for the preparation of concrete;
- hammers, saws and other carpentry tools;
- pliers and pliers for working with wire;
- metal cutting tools, for example, a hacksaw, jigsaw, angle grinder.
With an increase in the volume of work, the degree of mechanization of the process also increases. Excavators, concrete mixers, portable machines and powerful manual power tools are used.
Strip foundation marking and earthworks
Unlike the pile-screw foundation, the strip foundation is perfect for the construction of buildings with basements, basements and undergrounds. However, on heaving soil, this option will be quite costly - this type of foundation is best erected on dry soil, which swells less than wet. It will also be unprofitable to fill the foundation to a great depth, but for small houses, baths and garages, it is best suited.
Since it takes almost a third of the total cost of construction to prepare the foundation for construction, you should figure out in advance how to make a strip foundation correctly. It is also imperative to research the type of soil on the site and the depth of its freezing in order to understand whether this type of foundation is suitable for you at all. It will be much more difficult to correct your mistakes later.
Before you build a strip foundation, you need to clear the area of excess debris and start marking it. In accordance with the prepared project of a garage, bath or house, it is necessary to apply the outer and inner boundaries of the future foundation on the ground. This is done with the help of improvised means: wooden pegs or rods of reinforcement and rope (wire, strong fishing line).
It is necessary to apply on the ground the external and internal boundaries of the future foundation
How to mark the strip foundation perfectly even so that you do not have to rearrange the pegs from place to place:
- start the layout by defining the axis of the future building;
- using a plumb line, mark the first corner, and from it pull the cord or fishing line perpendicularly to the second and third corners of the building;
- then the fourth angle is determined by means of the square;
- check all the corners by measuring the diagonals - if the corners coincide, you can drive in the pegs and pull the fishing line between them;
- make the internal markings in the same way, stepping back from the external by 40 cm (the optimal width of the foundation).
When finished with the markings, study the surface differences in the area and select the lowest point. From here it will be necessary to start counting the depth of the trench in order to exclude further differences in the height of the foundation. For a small house, a pit depth of about 0.4 m will be enough.
The pit can be dug with your own hand with a shovel or with an excavator. Just do not dig by eye - be sure to check with a water level so that the bottom of the trench is as flat as possible, such a precaution will help to avoid many problems in the future. Do not forget that the walls of the trench must be strictly vertical.
The pit can be dug with your own hand with a shovel or with an excavator
Installation of formwork and reinforcement
At the bottom of the dug trench, a sand cushion is arranged, which not only reduces the load on the foundation in the off-season, distributing it over the entire base area, but also saves building materials. Sprinkle sand with a layer of at least 150 mm, level its surface with a water level and tamp it down with water. A layer of rubble can be poured on top of the sand cushion and waterproofing in the form of roofing material or plastic wrap can be laid to strengthen the strength of the base.
Before pouring the strip foundation, it will be necessary to build a formwork from available materials - plywood, wooden boards, pieces of metal, etc. The formwork is twisted with screws or knocked off with nails, while the heads of the nails are placed inside, so that later it would be easier to disassemble the structure, and the walls of the foundation turned out to be smoother. The installed formwork must protrude at least 30 cm above the ground surface. Inside the formwork, pull the rope along the entire perimeter to the level to which you will pour the foundation. Take care of the holes for the sewer and water pipes right away, otherwise you will have to cut them later, violating the integrity of the concrete monolith.
The formwork is twisted with screws or knocked down by nails
The next step will be rebar laying... Tie reinforcing rods with a cross section of 12 mm with a special knitting wire so that the sides of the square cells are 30 cm each.It is better not to use welding, since corrosion will appear in the welding places, and wire binding, in addition, ensures the flexibility of the structure when the ground moves. When laying the reinforcement in the trench, make sure that there is a 5 cm indent on all sides, then the reinforcement will be inside the monolith.
Filling the strip foundation with your own hands
Now let's figure out how to properly fill the strip foundation. Calculate how much concrete you need by multiplying the height, length and width of the foundation. You can prepare a concrete solution yourself by mixing 3 parts of sand, 5 parts of crushed stone and one part of cement, diluting with water to an optimal consistency. But it is better to use prefabricated concrete, because you will not be able to fill in the concrete prepared by yourself at one time, as a result, "cold seams" and cold bridges are formed, through which water will subsequently seep through, destroying the foundation. If you will pour the foundation using a machine, make sure that there is access for pouring from any corner of the formwork, and that the mortar in the machine has not had time to harden - if necessary, dilute it with water.
Video about pouring a strip foundation
Step-by-step instructions for pouring:
- concrete is poured little by little, in layers of 20 cm;
- each poured layer is carefully rammed with special wooden rammers to prevent the formation of voids in the monolith;
- for the same purpose, it is necessary to tap the walls of the formwork;
- pouring is carried out to the level of the fixed rope;
- at the end of the work, the surface of the poured foundation is leveled with a trowel, pierced in several places with reinforcement (so that air can escape), the formwork is tapped from the outside with a wooden hammer.
Filling is carried out to the level of the fixed rope
So, we figured out how to make a strip foundation, now it only remains to wait until it is completely dry - this may take about a month. At this time, cover the foundation at night with waterproof materials so that the rain does not wash away the cement from the surface, and during the day in sunny weather, pour water to avoid cracking the top layer. It is recommended to dismantle the formwork no earlier than two weeks after the foundation is poured, and preferably in a month.
Further maintenance of concrete
After pouring, it is important to provide conditions for its uniform hardening, first of all - the necessary temperature and humidity indicators. The complex of actions aimed at this is called concrete care.First of all, you need to cover the foundation, partially isolating it from the effects of solar radiation and other external factors. On cold, cloudy days, I do this in 8-12 hours after pouring, on sunny and windy days - in 2-4 hours. The surface of the concrete is covered with sawdust or sand, covered with burlap or other similar materials. Now you need to ensure a regular flow of moisture, for which the foundation is watered from a hose through a sprayer every 1.5-3 hours, depending on the weather in the daytime and at least twice a night.
Note! If the temperature drops below +5 degrees, humidification will have to be stopped. In this case, special varnishes and emulsions will help to retain moisture.
The care period depends on the brand of cement used. For fast-hardening varieties, 2-3 days are enough, standard cement is moistened within a week, and slow-hardening - up to two weeks. In addition, the configuration of the foundation must be taken into account - deep and wide structures require more careful maintenance.
Frequently asked questions
Is it possible to make a basement with a strip foundation?
A strip foundation can be considered the best option for implementing basement or cellar construction projects. It has sufficient penetration into the ground to withstand additional loads, provided that the basement is digged at some distance from the load-bearing walls.
How to make the floor correctly with this type of base?
The floor in buildings with such a foundation is created using the puff cake method. The soil is covered with sand, tamped and covered with crushed stone, a metal cellular screed is placed above, with a layer of waterproofing on it. Insulation and finishing layers of the floor are laid on the waterproofing.
The video shows the appearance of a strip foundation of a complex configuration with permanent formwork.
Video: DIY strip foundation
The strip foundation is quite reliable and can be used both for buildings made of timber, logs, and for low-rise buildings made of aerated concrete, cinder block, brick. It has sufficient bearing capacity and you can fill it yourself.
A specialist will tell you about the types of strip foundations: which foundation is suitable for different types of houses.
This video is about the technology of the device of a strip shallow foundation. It describes how to join the reinforcement at the corners, how to install the reinforcement, and make the formwork.
And here is a detailed story about pouring the foundation and concrete.
More on the progress of the construction of a shallow foundation. Detailed instructions:
This video tells about the nuances of building a buried strip foundation: the cost, for which houses it is suitable.
And here, about the construction of one of the varieties of the strip foundation - the foundation for the fence with bored piles. Theoretical information, diagrams and calculations are presented.
Excavation works, formwork installation, concrete pouring are shown here.
Advantages and disadvantages of strip foundation
Before arranging such a foundation for a house, study all the "pros" and "cons" of the structure. This also applies to a monolithic tape base.
The advantages of this reason are:
- simplicity of the device
- the ability to withstand loads from the weight of the structure and soil pressure
- no need to perform a large amount of earthwork
- the possibility of arranging a basement when the groundwater level is located at a depth of 1.5 m from the surface
- application on all types of soil, even on heaving, subject to the performance of high-quality waterproofing, storm sewers, drainage and insulation.
The deepened base has the following "disadvantages":
- sometimes it is necessary to carry out complex earthworks and use heavy construction equipment
- the need to carry out work on insulation and waterproofing
- the impossibility of erection when the groundwater is at a level above 1.5 m.
Strip foundations are often used in the construction of houses and cottages.
A strip foundation made of reinforced concrete serves for many years even if the house is erected from solid bricks. The cost of such a foundation is much lower than a screw pile structure.
DIY pile-grillage foundation
The construction of such a foundation does not require special skills and experience, so those who want to build a house can cope with this task on their own.Consider the step-by-step instructions for installing the pile-grillage foundation with your own hands.
Cleaning and marking the territory
Site preparation is one of the most important stages of construction, the quality of which will determine the comfort of further work. The first thing to do is to remove all excess debris and plants.
Preparation of a land plot for the construction of a residential building using a small bulldozer and an excavator
If a landscape design is provided on the territory, it is necessary to carefully remove all weeds. If you plan to plant a lawn or a garden bed, the top soil layer (4-5 cm) is removed.
Also at this stage, the marking of the site is carried out. It is necessary for more accurate installation work (even pouring of the grillage and installation of piles in a predetermined place).
Layout of the site for the foundation
To make the correct markup, the drawing from the drawing must literally be transferred to the ground. It is important that all dimensions exactly correspond to the parameters specified in the drawings.
To work you will need the following materials:
- a hammer
- rope (line)
Places for piles are marked separately. They are distributed over the area in a certain order so that a certain level of load falls on each support (from 800 to 1600 kg).
Layout scheme of the site for the construction of the foundation: 1 - base peg, 2 - reconciliation of diagonals, 3 - plumb line, 4 - level
Drilling a well for piles
Further, earthworks are carried out. They dig holes for piles and trenches for foundation tapes. The walls and bottom of these trenches are carefully tamped, and a cushion of sand and gravel is sure to fill up.
Pile wells are drilled with a garden or hand drill. You can also resort to the services of crane boring machines, but it should be borne in mind that this will lead to an increase in the estimated cost of construction by about 10%.
If the drilling of wells under the pillars will be carried out with the help of technology, it is necessary to ensure unhindered access of the machine to the place of work.
The depth of each hole is made 50 cm deeper than the level of soil freezing. The diameter of each hole should be slightly larger than 1/3 the width of the foundation strip. The first 30 cm must be covered with sand and carefully tamped. This will help protect the metal parts from moisture in the soil.
Schematic representation of the underground part of the foundation
Installation of piles for the foundation
Now we form a "pile field", that is, we install the piles in their places. For the construction of simple buildings, they can be evenly distributed around the perimeter in rows.
At the design stage of the pile field, you should remember the following details:
- The choice of piles depends on the type of soil
- How close to the surface is groundwater
- The diameter and length of the piles depends on the final mass of the structure (the larger the house, the more powerful, and therefore more, there should be piles). It also depends on the type of grillage.
- The bearing capacity of the supports must be calculated.
We proceed directly to the installation of piles. For them, formwork, reinforcement are made, and after that the holes are poured with concrete. It is recommended to start pouring concrete only after all the earthwork has already been done.
The material for the piles is usually metal or asbestos-cement pipes of large cross-section.
Screw piles can be used, for the installation of which there is no need to carry out earthwork. The installation of piles into the ground takes place in several stages:
- We make a hole 10-15 cm deep in the pre-marked place for the piles.
- We put the pile screw into it and start screwing it in. This will require 3-4 people.
- In the course of screwing in, be sure to check the evenness of the entry of the support into the ground using a building level.
For each support, it is imperative to make a "heel" on which it will stand securely. To do this, sand is poured into the well, the pile itself is placed in the well and poured with concrete (about 40 cm). Then the support is raised (30 cm) so that the concrete spreads underneath and creates a support cushion.
Technology of pouring bored piles
Formwork for the foundation
Before starting the installation of the formwork, it is necessary to make a pillow at the bottom of the trench. To do this, 10-15 cm of sand is placed on the bottom, it is poured with water and carefully tamped. Crushed stone is poured onto the sand from above.
Formwork can be bought in a store or made independently from ordinary boards, chipboard panels. So that the material for the construction of the formwork can be reused, it must be wrapped with plastic wrap.
- Initially, along the perimeter of the future growth, we drive in stakes every meter, to which we mount the formwork panels so that the support stakes are on the outside.
- So that the shields do not disperse, an additional support is nailed in the upper and lower parts. Particular attention should be paid to the formwork elements at the bottom corners.
Do-it-yourself formwork for pile-grillage foundation
Reinforcement of piles and grillage
Reinforcement is an obligatory stage in the construction of the foundation, which helps to strengthen the entire structure as a whole. For this, after preparing the formwork, a three-dimensional mesh is assembled from metal rods inside it.
Reinforcement of the pile-grillage foundation
Piles are also necessarily reinforced. To do this, take three rods and connect them in the shape of a triangle, and then put them in place.
The rods should protrude 20 cm above the pile. Sometimes, to further strengthen the structure of the rods, a circle is assembled completely.
Foundation piles made of reinforcement
When pouring concrete, some subtleties must be taken into account:
- The density of the finished solution should be medium.
- All reinforcing bars must be connected before pouring concrete.
When concrete is poured, a certain pressure is created, therefore all formwork elements must be strong, airtight and resistant to loads
- First of all, all support piles are poured with a concrete mixture. They are left for 1-2 days so that the structure dries out a little and becomes more durable.
- After that, the tape itself is poured. For this, it is recommended to use several concrete mixers and pour the mixture at several points at the same time.
- We leave the foundation to dry for a week. If necessary, the grillage surface is leveled.
Pouring mortar from a concrete mixer
Heat and waterproofing of the foundation helps to protect the foundation itself from moisture and dampness, as well as the foundation materials of the house.
Subtleties of waterproofing:
To protect the piles, roofing material is wound into a roll and in this form is placed in the well. In the trench for the tapes, this material is completely covered with the walls and the bottom. For reliability, roofing material can be coated with hot resin on top.
In the pile-grillage foundation, the side walls of the foundation are insulated, which act as a plinth. To do this, use: foam or expanded polystyrene, bitumen, etc.
Waterproofing the upper part of the foundation
To protect the substrate from dampness and mold, it is also important to take care of the ventilation holes (air vents). They are made using small pieces of plastic pipe.
It is laid at a certain level of the tape during the pouring of concrete, the pipe contour is sprinkled with sand so that it can be easily removed. When the foundation is completely dry, the pipe is removed.
Air vents ensure correct and uniform ventilation of the entire foundation
Now you know how to make a pile-grillage foundation with your own hands, using the knowledge gained from studying this article.
Pros and cons of window frame greenhouses
The undoubted advantage of such a material is that it can be built very quickly. Almost any person is able to cope with the work. Another advantage of a window greenhouse is that it is budgetary, but not inferior in quality to greenhouses made of expensive materials. It is sealed and transmits light well, windows can be opened for ventilation.
A greenhouse made of window frames will significantly save on the construction of a greenhouse
Disadvantages are inherent in those greenhouses that are made of wooden frames with glass. Every year, such a structure requires repair, due to the fact that the tree dries up. In addition, you need to be very careful with this design. Glass is a fragile material that loses its aesthetic appearance over time. It is necessary to constantly wash the windows so that the light can easily penetrate into the room. And also such a structure requires a concrete base underneath.
The foundation is needed for several reasons:
- wooden frames can quickly rot in contact with the ground
- the soil tends to "move", which can damage fragile glass.
In addition, the base will slightly raise the ceiling of the future greenhouse, and it will be much more convenient to be in it.
Photo gallery: homemade double-glazed greenhouses
A greenhouse made of old windows looks very aesthetically pleasing.
A greenhouse made of metal-plastic windows allows you to create optimal conditions for plants
A greenhouse made of old windows is inexpensive
You can always additionally decorate the greenhouse
A greenhouse from old windows can be small and large
Installation of a greenhouse from window frames will not take much time
Digging a trench to fill the foundation
The second stage will be digging a trench for a strip foundation or drilling wells for a pile foundation. In the future, a strip foundation will be poured into the trench, and piles are installed in the wells, therefore, special attention should be paid to the accuracy of these operations. In particular, the walls of the trench should be reinforced with planks that form the foundation formwork. Instead of boards, it is quite possible to use any other suitable material, however, wooden boards are beneficial for their strength, low cost and ease of work with them. The bottom of the trench should be below the freezing depth of the soil. The minimum difference between these levels is 20-30 cm. The depth of the wells depends on the density of the soil and is usually about two meters.
When pouring a strip foundation, it will also be necessary to create a sand cushion at the bottom of the trench. This is done by pouring a layer of sand, followed by pouring it with water and tamping. The thickness of the sand cushion depends on the soil characteristic such as heaving. A layer of tape waterproofing material must be laid on top of the sand.
The cost of work on the installation of a columnar foundation
The total cost of a columnar foundation consists of the sum of the cost of materials and the cost of the actual work. In most cases, it is much lower than the cost of other types of foundations, since almost all types of columnar foundations can be built with your own hands. Videos and photos, instructions and guides found on the Internet are also usually cheap or free.
The calculation of the cost of most types of columnar foundation can be done independently using special online calculators or programs. Many of them are quite easy to find on the Internet, are free and have an intuitive interface.