If there is cheap “bedded” natural stone in the region, a do-it-yourself rubble foundation will cost much less than a monolithic or prefabricated structure made from FBS blocks. Rubble is not sorted into fractions and does not have smooth edges, so instead of cords for masonry or pouring, formwork is often used.
Rubble stone ensures a reduction in the foundation construction budget by at least one and a half times. The strength of the structure is comparable to a monolith, the main filler of which is the same material, only of smaller fractions. Basement part the house does not have to be decorated; the underground part is waterproofed by treating the seams with special compounds.
The construction of a rubble foundation is similar to masonry or concreting. In the first case, a cement-sand mortar is used with the addition of penetrating mixtures or liquid glass, which impart water-repellent properties.
There are two options for constructing a rubble foundation:
- concreting with laying rubble stone;
- rubble masonry.
The foundation is made using rubble masonry.
Attention! If the rubble concrete foundation is not planned to be lined in the basement, this massive structure will become a cold bridge. Heat loss through floors and ceilings will increase, since at subzero temperatures the material will freeze through.
Earthworks and foundation
At the stage of moving the full-scale axes of the house into the building area, it is necessary to take into account several factors that significantly affect the productivity and quality of work:
- the size of the stone is much larger than the brick, the tape is 45 - 60 cm minimum;
- It is very difficult to reinforce masonry, so sometimes plaster mesh or fine mesh Chain-link mesh are used;
- even for masonry, it is better to make formwork that can be moved in height, which will sharply increase the pace of work;
- The rubble material should be sorted into small and large stones before starting work.
The construction of trenches is standard, 0.5 - 0.7 m is added to the width of the tape from the inside (comfortable for rearranging the formwork, opening joints), 1.2 m from the outside (necessary for insulating the blind area, laying drains). The trench is dug to the design depth, since below the freezing mark there are guaranteed to be no heaving forces, and there is no need for an underlying layer of non-metallic material.
Attention! If you plan to pour a rubble concrete foundation, in order to avoid leakage of cement laitance into the lower drainage layer, it is necessary to make a footing 5–10 cm thick, twice the width of the tape, and fuse 2 layers of rolled waterproofing onto it.
Features of formwork design for different technologies
The technologies for rubble masonry and concreting a foundation strip using rubble stone are very similar. The differences are:
- when laying, stones are laid on mortar;
- When concreting, the formwork is filled to 30 cm with concrete, into which large stones are embedded.
Unlike brick, rubble has an uneven shape and it is very difficult to lay it along a thin cord. Therefore, it is easier to fix two shields along the outer and inner edges of the tape in order to lay the stones close to them.
Therefore, the formwork design for these two technologies for building a house foundation will be different:
- for concreting, standard shields will be required for the entire height of the tape stretched along the inner surface plastic film so that the mixture does not flow out through the cracks, the concrete does not dehydrate upon contact with wood;
- for masonry, a shield 30–50 cm high is sufficient, so that it can be conveniently moved in height as the foundation walls are built up.
Attention! It is not recommended to use slot foundation technology when the formwork is trench walls. If the soil does not crumble from its surfaces, this indicates a large percentage of clay, which is guaranteed to swell in winter and destroy the masonry. It is necessary to widen the trench, lay drains, backfilling sand, ASG.
For secure support wall material At home, on the upper edge of the rubble foundation, it is necessary to select stones with a flat surface for the last row. Unlike classical masonry, the construction of a rubble structure is more reminiscent of concreting:
- a film is laid on the underlying layer;
- a bed of mortar 3–5 cm thick is applied to it;
- two longitudinal rows of stones of approximately the same size are installed;
- then the mortar is laid again, the bed is leveled;
- ligation is performed with a butt row on the outer or inner side;
- in the third row the poke is placed on the other side;
- then several rows of spoons are installed (long side along the wall);
- At the corners it is necessary to bandage with whole, ¾ stones.
Some experts wet the stone with water (dipping before installation without soaking). However, this material is not fired in ovens and usually has natural moisture, so the procedure is not necessary.
Attention! The consistency of the solution should ensure that the joints in the previous row are completely filled. To increase plasticity, add a Superplasticizer or a few drops (5 - 7 per concrete mixer) of Fairy type detergent.
Concreting using rubble stone
Laying the rubble concrete mortar into the formwork is a little more difficult; you will need a reinforcing bar or an internal vibrator. The crushed stone fraction in the mixture should be fine (5/10 mm) for better filling. The technology looks like:
- laying concrete - a 30 cm layer is poured inside the formwork without compaction;
- stone distribution - the rubble is not covered, but laid out in a 20 cm layer so that the outer edges come into contact with the formwork panels;
- recessing the rubble - with fittings or the tip of a deep vibrator, on which a special visor is put on.
After immersion, the stones should not stick out from the concrete. The break between laying the mixture and stones should not exceed a quarter of an hour. If it is planned to stop work, concrete or rubble runs out, the laid stone must be covered with a mixture compacted with a vibrator attachment.
Attention! The upper 30 - 50 cm are concreted without stone; before laying the mixture, a rubble is installed on the last row reinforcement cage so that the upper belt of the longitudinal rods is recessed into the concrete by 2 - 5 cm (standard protective layer).
Waterproofing
Depending on the technology used for making the foundation of a house using rubble stone, the surface of the tape does not have the same roughness. Therefore they apply different ways waterproofing of the underground part:
- rubble concrete foundation - the surface is more even, possible over a primer;
- rubble masonry - the surface is uneven, plastering with moisture-resistant mixtures, coating with bitumen, polymer or epoxy mastics is used.
Attention! If penetrating compounds are introduced into the solution or concrete, waterproofing of the structure is not required.
Advantages and disadvantages
The main advantages of rubble strip foundation houses are traditionally:
- reduction of the construction budget;
- reducing work time through the use of large-format material;
- high performance characteristics(weather resistance, strength).
The disadvantage of rubble masonry is the lack of reinforcement and excessive mobility of elements inside the structure. When concreting into formwork using rubble stone, there are no disadvantages at all. The tape can be qualitatively waterproofed and covered with thermal insulation. She happens to be monolithic design with an upper reinforced belt, which compensates for tensile loads from possible swelling of soils.
Thus, the construction estimate country house can be completely reduced through the use of budget building material. It is more difficult to work with rubble stone than with brick, but the large format allows you to reduce construction time.
Historically, the rubble foundation is the oldest foundation, still popular for the construction of 1-2 storey buildings. Buildings built in antiquity on rubble foundations still stand today. The service life of a stone foundation is now estimated to be at least 150 years. Such bases are most resistant to freezing and exposure groundwater. And natural stone is a beautiful and environmentally friendly material.
There are strip rubble foundations and columnar foundations
To make a decision, let’s look at the rubble foundation and take into account all the pros and cons. Remembering that the foundation is the most important part of the building, let's get started.
The advantages of buta bases include:
- Durability. Natural stone is more durable than concrete, and the service life of a rubble foundation is usually more than 150 years;
- Environmental cleanliness;
- Water resistance rubble concrete foundation higher than reinforced concrete;
- Masonry made of large natural stone has an attractive appearance.
It is important to know about the disadvantages. The disadvantages of a rubble foundation include:
- Relatively high price of buta when purchasing it;
- Laying stone is a longer process than pouring a reinforced concrete base;
- Natural stone laying skills required.
Please note that a large bottle can weigh more than 10 kg. Working with stones weighing more than 30 kg is not recommended
Rubble stone, which one to choose?
Cote is not a specific type of rock. Rubble stone is a torn or rounded natural stone ranging in size from crushed stone to large stones whose weight can exceed 30 kg.
Natural stone in construction is used in different types: light, heavy sedimentary or volcanic.
Rubble strength
Depending on the rock, the strength ranges from 2 MPa to 30 MPa.
Frost resistance
The frost resistance of rubble is assessed by the number of cycles of successive freezing, while the stone should not crumble and lose no more than 5% in weight. This parameter models the number of cold seasons for a buta without destruction.
15 or more cycles are acceptable.
The quality of the cement mixture (in terms of strength and frost resistance) must correspond to the selected stone
Flakiness
A characteristic that determines the shape of grains in a stone. There are 5 groups, depending on the content of lamellar grains from 10% (group 1) to 35-50% (group 5).
Flakiness affects strength (1 group is stronger than others), and somewhat increases the labor intensity of working with such a stone.
Radioactivity
Rocks can be dangerously radioactive.
In construction, 2 groups of rocks according to radioactivity are allowed:
- Up to 370 Bq/kg – allowed for the construction of residential buildings, as well as construction inside populated areas;
- Over 370 Bq/kg is not allowed for the construction of residential buildings, as well as construction inside populated areas (such material can only be used for industrial buildings).
Rubble stone is distinguished by shape
When choosing a rubble for the base, you need to decide not only on the type of rock, but also on the shape.
Depends on the form:
- ease of laying, which affects the work time;
- appearance;
- consumption of cement mixture.
Rounded bottle
A stone that was mined in the surf zone, in places where glaciers exist today or during the Ice Age.
This stone has a rounded, rounded shape. This kind of rubble is not suitable for a foundation.
Bedbed
A butte, the two sides of which are close to parallel, is called bedded. It turns out something like uneven natural brick (if you look at it uncritically). Thickness not less than 70 mm.
Unlike rounded ones, bedded rubble is most convenient for masonry; it also allows for dry masonry (without mortar).
Species from which bedded rubble is produced:
- Sandstones
- Limestones
- Layered rocks
Industrial bottle
Natural stone is extracted using blasting. After sorting into fractions it goes into sale. Has a “ragged” shape
Not in good condition
The stone must be clean, not crumble and not crumble when hit with a hammer.
A ringing sound when struck with a hammer is good!
DIY rubble strip foundation
We suggest learning how to build a rubble foundation for a house with your own hands. You can both seriously save money by carrying out the work yourself, and control the work on the construction of a rubble foundation, understanding the process.
Calculation
To calculate, you need to collect:
- Weight of the superstructure (walls, windows, floor, ceiling, roof, utilities);
- Maximum payload (finishing, furniture, residents, water supply and heating);
It is also necessary to determine the soil parameters on the site.
- Soil type;
- Freezing depth;
- The height of groundwater.
Let's say:
- weight per foundation 50,000 kg;
- building size in plan 4 x 3 m;
- without basement;
- located near Tver;
- soil – loam (soil resistance 1.5 kgf/cm2;
- groundwater below 3m;
- Freezing depth 1.4 m.
Calculation of the foundation body
Foundation support area:
50,000 / 1.5 *1.3 = 43,333 cm2 or 4.33 m2 (1.3 – safety factor)
The minimum width of a rubble strip foundation is 40 cm. If necessary, increase the foundation support area
The perimeter of the building is 14 m.
With a foundation thickness of 40 cm, the foundation support area will be:
14 * 0.4 = 5.6 m2
The depth of the foundation should be 20 cm greater than the freezing level.
Freezing depth of various soils by region, m
The height of the foundation base (height above ground level) is recommended to be 40 cm or 20 cm above the snow cover (whichever is greater). In our calculation we will take 40 cm.
Foundation volume:
5.6 * (1.4 + 0.2 + 0.4) = 11.2 m3
For 1 m3 of foundation you need 1 m3 of rubble and 0.35 - 0.5 m3 of cement-sand mortar for masonry.
11.2 m3 of rubble
3.9 – 5.6 m3 of solution
Calculation of material for a cushion on a rubble foundation
Please note that the width of the ditch under the foundation strip should be 60 cm greater on the side where the mason will move, and 30 cm on the opposite side (provided that the width of the foundation allows working on one side).
A sand cushion is, first of all, needed to level the bottom of the pit and to distribute the load on the ground evenly.
The thickness of the sand cushion is 20 cm (minimum).
To reduce labor costs, we will lay the foundation in a trench with the following width:
0.4 + 0.3 + 0.6 = 1.3 m
The volume of the sand cushion will be:
1.3 * 0.2 * 2 * (4 + 3) = 3.64 m3
Taking into account the reserve (including for leveling) 30%:
3.64 * 1.3 = 4.7 m3
Preparatory work
- Marking the foundation;
- Digging a pit;
- Leveling the bottom of the pit;
- Laying a sand cushion (preparation);
- Wash and sort natural stone:
First of all, you need to wash the stone from dirt and check whether it is good (the stone should not fall apart when hit by a hammer, it should not peel off).
If there are stones larger than 30 kg (or the weight that you have determined is comfortable for masonry), you need to break them.
The first one will contain small stones. We will use them to fill the voids in the masonry between large stones.
The second group will include stones convenient for laying out corners and junctions. These stones are distinguished by more large size and relatively regular shape.
The third group is all other stones.
Rubble masonry
Now it's time to move on to laying the stone. Please note that with the exception of the first layer, the stones are laid on mortar.
This is important: the stones should not touch. Leave a gap of 3–5 cm between the stones in the row.
The stone must be wet before laying.
a stone laid along the foundation is called a spoon, and across it is called a poke
There are three technologies for rubble masonry: “under the shovel”, “under the gulf”, “under the bracket”.
Under the shoulder blade
Rubble stone is uneven, and rows of it cannot be made even. But you need to try so that the next row, as it were, compensates for the unevenness of the previous one and all rows are relatively parallel.
- The first to be laid is the bonded row on a cushion without mortar, the stones are compacted, the voids between the large stones are filled with small stones or crushed stone;
- A layer of concrete is laid ( cement-sand mixture in a ratio of 1:3, cement grades M400 or M500), the concrete must completely cover the stones;
- The spoon layer is laid;
- Continue alternating the bond and tray layers on the concrete mortar until the design height of the foundation is reached;
- To level the horizontal surface of the foundation, use thicker concrete.
Observe ligation of stitches!
Under the bay
This type of masonry is made without selecting stones or bandaging voids.
- The rubble is laid in rows;
- Filled with mortar (cement-sand mixture 1:3 from cement M400, M 500) and compacted (it is recommended to use vibrating mortar compactors);
- Repeat until the target height is reached.
This method requires formwork. The size of the buta is not so important. Rubble foundation, made using the “flooded” technology, has reduced strength.
Under the bracket
The method is almost no different from “under the blade”, except for leveling the stone in height using a measuring bracket (which gave the name to the masonry method). This reduces the complexity of masonry, but increases the complexity of preparatory work.
After gaining 50% strength, you can move on to subsequent work.
At an average daily temperature of 20°, concrete gains 50% strength in three days
Any home craftsman can lay a rubble foundation with his own hands. And he will not need any special equipment or any specific knowledge. It is enough to understand the simple technology of constructing rubble stone foundations.
Experts say that rubble foundations for various buildings have been erected for more than 4 thousand years. In the Middle Ages, durable and aesthetically attractive rubble was used to make reliable strip foundations not only for houses, but also for powerful fortresses and defensive structures. Structures made from this stone last 150–500 years, demonstrating unique performance properties.
Rubble foundations for houses are absolutely environmentally friendly. They perfectly resist the effects of soil water and do not lose their characteristics when frozen.
Reliable foundation made of rubble
A rubble base is understood as a strip structure built from natural large-sized stones, which are filled with cement-based mortar.
This natural material is not divided into separate categories based on its size. For this reason, it may contain fractions with different geometric parameters - from 15 to 50 cm.
To build a foundation for a house, it is recommended to use stones with relatively wide and even upper and lower edges. Such material is usually called bedded. But it is also possible to use stones that are less correct in terms of geometry. Their shape does not affect the strength of the constructed foundation in any way.
Nowadays, rubble is most often used to build foundations for 1–2-story houses, as well as for various commercial buildings. The technology for constructing standard five-story residential buildings from rubble stone has existed for more than 60 years. A minimum of financial resources are spent on the construction of such buildings, due to the low cost of natural materials.
It is impossible not to separately note the natural beauty of natural stones. You can use them both to build a solid foundation for your house and to furnish the basement of your home. In the latter case, you will not have to spend money on finishing measures. The rubble base does not need to be plastered or tiled. It will look truly luxurious anyway.
On clay soils, high-density loams and sandy soils, rubble foundations last up to 150 years without any repairs. If such a foundation is being built on heaving ground that is prone to subsidence, the structure should be strengthened with reinforcing elements. And it will serve you for the same 150–200 years.
The quality of rubble for laying foundations for residential buildings is determined very simply. You just need to hit the stone well with a regular hammer. If the bottle does not break from a strong blow and at the same time produces a clear and ringing sound, it means that you have excellent material in front of you.
Stones are also checked for quality by splitting them. If you break the rubble, and it does not generate dust and does not break into small fractions, feel free to use it to build a foundation. Believe me, a foundation made of such stone will last for many decades.
Rubble house foundation
The rubble must be washed before laying. This procedure, let’s say right away, is labor-intensive. Please be patient and have some free time. You have to thoroughly wash every stone. If this is not done, the concrete mixture will not bond with the stones at the proper level, which will significantly worsen the strength of the foundation.
Large pieces of rubble for laying the foundation of a house require additional preparation - breaking them into smaller stones weighing no more than 30 kg. This procedure is called plinting. It is done with your own hands using the following technology:
- Using a soft pencil, draw a line on the stone along which you plan to break the rubble.
- Stretch the nylon rope and forcefully press it into a piece of pre-prepared chalk.
- Pull the cord marked with chalk over the line marked on the stone and suddenly release the rope. As a result, you will get a clearly visible chalk mark on the rubble. This is where the material needs to be split.
- Use a hammer to drive a steel chisel into the cut line on the rubble. You are splitting a stone. The hammer blow should be performed quite firmly. Do not be afraid. A high-quality stone, as we said, will not crumble, but will clearly separate into separate fractions along the split line.
Now that the material has been prepared, you can proceed directly to laying the foundation for the house.
The laying of the structure we require is carried out in several stages:
- Clearing the land.
- Dig a trench of the required size. The ditch must be made with a small margin. Maintain a distance between the boundary of the future foundation and the edges of the walls (load-bearing) of the house being built at a level of 15–20 cm. The depth of the trench is below the freezing mark of the ground in your area.
- You do. It will protect the ditch from soil falling into it. The formwork structure is dismantled immediately after pouring and setting of the concrete mixture.
- Place a 30-centimeter sand cushion at the bottom of the pit. Sand must be poured into separate layers, tamping each of them.
- Lay sheets of roofing felt over the made pie. They will be an excellent waterproofing material for the foundation.
Creating a rubble stone foundation
After this, start laying the rubble. It must be moistened with water before starting work. Then the stones will adhere well to cement mixture. Note! Stones cannot be placed back to back in the trench. Leave a small gap between individual pieces of rubble.
The masonry technology itself is simple. You need to remember that the short side of rubble stones is called a poke, and the long side is called a spoon. In one row of spoons should alternate when laying with a poke. The total thickness of the masonry is usually taken at 0.6–0.7 m. For a residential building, this is quite enough. Installation of stones is carried out using a small sledgehammer or a massive hammer.
The construction of a rubble foundation is carried out according to three different schemes. The operation can be performed “under the bay”, “under the scapula” and “under the bracket”. If you plan to make formwork, it is recommended to implement the “flooded” scheme. It is given below:
- Place the butt row in the prepared ditch (on a sand bed). Pour fine gravel or crushed stone into the gaps. Compact the layer.
- Fill the stones with liquid concrete (3 parts sand plus 1 cement).
- Lay the spoon row. Repeat all the described procedures.
The topmost row is filled with thicker concrete (add less water to the mixture). The layer of mortar should have a thickness of about 0.5–0.6 m. Then, using a vibrator, compact the concrete until the mixture no longer penetrates into the gaps between the rubble stones.
Creating a foundation from rubble
Important point. If the foundation is developed according to the “bay” scheme, only light buildings (for example, a small or outbuilding) are allowed to be erected on it. Structures with a large mass are not installed on such a foundation.
For loaded houses, the foundations are usually built according to the “shovel” and “bracket” schemes. In the first case, you are allowed not to choose a bottle by size. But the “under the bracket” option involves careful selection of stones in height (it should be the same for all pieces used).
Laying according to these two options is done as follows:
- Place the bonded row dry on a bed of compacted sand.
- Compact the stones, pour small stones into the gaps between them.
- Pour liquid concrete.
- You install a row of spoons, tamp it, pour the concrete mixture.
- Next, lay the bond row again, then the spoon row, and so on.
Note! It is imperative to tie the seams between all mounted rows with reinforcing bars and steel wire. You need to ensure that the rubble in the masonry does not wobble, but stands really firmly.
And one last point. When installing rubble in rows, you must constantly monitor the horizontal and vertical positions of the corners of the masonry and the surfaces of the stones themselves. Then you will have an impeccably reliable foundation.
The construction of any house involves the construction of a foundation. For its construction, in order to save money, you can use this natural stone, like but. This is one of the cheapest natural materials.
In its structure, rubble stone is quite hard, so a foundation built from it will be reliable and durable for many years.
You can make such a foundation yourself, without the help of specialists, which will significantly save your budget. Building the foundation for a house is quite hard work, but it is possible to carry out this activity with your own hands if you work hard. It should also be noted that when the construction of a rubble stone foundation is mentioned, this means the construction of a strip foundation. You can build a pillar foundation, but technological process will be quite difficult. Therefore, preference is given to the first option.
List of necessary building materials and tools
Before starting construction, it is necessary to purchase the following materials:
- Stone. Its size along the longest diagonal should not exceed 50 cm. When choosing this material, pay attention to the fact that it does not have defects on its surface and is clean. It must also meet standards such as strength, frost resistance and water resistance.
- Small crushed stone for backfilling voids.
- Sand for forming a base for and for mixing cement mortar.
- Cement used to mix mortar. Moreover, the higher its grade, the stronger and more reliable the structure will be.
- Ruberoid will serve as a waterproofing layer.
In order to begin building the foundation of the house, prepare the following tools:
- Shovels: shovel and bayonet.
- Container for mixing the solution.
- Trowel.
- Water and horizontal levels.
- Hammer-pick, sledgehammer, mallet, rammer, chisel.
- Roulette and plumb line.
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Preparatory work for the construction of the foundation
So, having prepared all the building materials and tools, let’s begin building the foundation of the house with our own hands. First you need to dig trenches. Their depth should be below the soil freezing level. And its width should be such that the foundation being built is 20-30 cm larger than the walls, but not less than 40 cm. You also need to decide whether formwork is needed or not. Formwork is used in cases where the soil is quite loose and susceptible to crumbling. Upon completion of the work it is removed. If the soil on your site is quite dense, then you can refuse to build it.
Then you need to make a sand cushion at the bottom of the trench. Its thickness can vary from 15 to 30 cm. Sand must be poured in several stages. Each layer of sand must be compacted using a tamper. To make this process easier, water sandy base water.
A waterproofing layer is laid on the sand cushion thus formed. To do this, you need to take sheets of roofing felt and place them at the bottom of the trench. Lay them overlapping to avoid gaps between the sheets. This layer of waterproofing will prevent the cement mortar from seeping into the sandy base.
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Technological process of building a stone foundation
Now that everything is prepared, let's start laying rubble stone with our own hands. For the first layer of the foundation, it is necessary to select in advance stones that have flatter horizontal surfaces. If there are not enough such stones, then you will need to arm yourself with a hammer and chisel in order to give this material the necessary shapes.
At the corner points of the future foundation and at the intersections of walls, you need to place stones with your own hands with the most even surface, and they must be strong enough. When laying the first row of stone, place them along the trench. Press the rubble into the sand so that it lies tightly there and does not wobble.
After laying the rubble directly between the stones, the voids are filled with crushed stone. Then they begin to fill the laid and compacted stone with thin cement mortar. This is done so that the liquid solution can penetrate and fill all the voids.
It is quite simple to prepare this mixture with your own hands: to do this, take 1 part cement and 3 parts sand. These components must first be sifted so that the future solution does not contain various pebbles and debris, since the quality of the mixture depends on this. Mix these ingredients thoroughly using a shovel. Then add water little by little and mix everything at the same time. Add liquid until you get the desired result.
It is advisable to prepare this mixture from cement, the grade of which is not less than M-100. Then a layer of rubble stone is covered with the same cement mortar, but already thick. When the stones are tightly adjacent to each other, the thickness of the cement layer should be minimal. The second row of building material must be laid across the trench. That is, the location of the buta in two adjacent rows will be perpendicular. In this way, the rows are ligated.
First of all, when building a house, you need to decide on the foundation. Solve the questions of what type and what material it will be made of, what type of insulation and waterproofing to use.
If we talk about the material, the choice will be represented by concrete, rubble and rubble concrete options; asbestos-cement pipes are also used for the construction of the foundation. Most often, rubble is used to build a private house.
What is rubble and rubble foundation
Rubble or rubble stone are stones obtained as a result of the development of rocks such as limestone, sandstone, and dolomite. It is either stones of various shapes with irregular angles and irregular shapes, or stones with smooth edges - slabby or bedded.
A rubble foundation, often of the strip type, is a masonry in which auxiliary materials (liquid mortar on clay, lime or cement) require a relatively small amount for its execution. Priority can be given to bedded rubble and stone of the correct shape. Firstly, they are obviously more convenient for laying - even edges and corners are much easier to lay closer to each other, and secondly, the strength of masonry made from bedded and regular stone is 1.5 and 3.5 times higher than from crushed stone, respectively.
What you need to know when choosing a foundation
Disadvantages of a rubble foundation:
- the construction process itself is very long, labor-intensive and expensive;
- it is difficult to ensure construction “with your own hands”;
- long preparation for construction.
The rubble foundation has the following advantages:
- does not require protection from moisture and decorative treatment;
- strength and long service life;
- resistant to water and frost;
- quarry is a material of natural origin.
From the above, we can conclude that a rubble foundation is suitable for a fairly large private house, which requires increased strength and is also designed for a very long service life. But strip foundations made of rubble can also be used for a variety of small buildings, from a cottage to a bathhouse.
Do-it-yourself foundation
A strip foundation made of rubble is perfect for a country house. It is also possible to build a columnar one, but it is much more difficult than the first one.
The first step is to decide on the volume of material. The size of the foundation in height is calculated based on the fact that it must be buried 20 cm below the freezing depth and at least 30 cm above the ground level. The width of the base should be 20-30 cm greater than the width of the wall. Having calculated the volume of material, it is better to purchase it with a small reserve. You will need sand for a pillow under the foundation; you can calculate the volume, knowing that the thickness of the pillow will be about 20 cm. Next, you need to select and prepare the material, if the latter requires it in size or shape. The cement for the liquid mortar must be of a grade not lower than M100. The rubble stone for the foundation must not only be clean and free of cracks, but also not exceed 30 kg. The larger one is chopped to the desired size. This process is called plinting, sometimes after it pinning is done - changing the shape of the stones closer to a parallelepiped. Immediately before laying, the stones must be cleaned of dirt and wet.
To lay a rubble strip foundation, a trench is dug; its depth is determined based on the fact that the foundation must be at least 20 cm below the freezing depth. A layer of sand about 15-20 cm thick is poured onto the bottom of the trench and thoroughly compacted. It should be noted that in heaving soils first of all, gravel is poured, and then sand. Afterwards the formwork is installed. Next, roofing felt is laid, this is done with an overlap. When installing a strip foundation, masonry is used “under the bay” in opposition to the formwork or trench walls, if the formwork was not installed. The first layer of stones is made of the largest and smoothest stones. This row is laid along the base, compacted, filled with crushed stone and filled with liquid cement mortar. The next row is laid across the trench, the next along, and so on, alternating the direction of laying.
Having examined the process of building this foundation, you can make sure that it is really lengthy and quite expensive, if you involve hired workers, if you build it yourself, the price of construction will be lower, although this work will take a lot of time and effort. If there are any, the result will be durable, strong, resistant to water and frost, and beautiful.