The foundation is the foundation of the house; the stability of the entire structure depends on its strength and reliability. To keep it from the external environment for a long time will allow insulation in parallel with waterproofing. The available technology for installing heat-insulating materials allows you to do the work yourself.
A concrete or pile foundation is regularly exposed to moisture, low temperatures, dynamic loads of moving soil. Through it, the cold enters the basement and inside the house. External insulation of the foundation has advantages over the internal one:
- The formation of condensation on the walls is excluded.
- The surface of the foundation is protected from moisture and heaving soil.
- External thermal insulation allows you to maintain a positive temperature in the basement and prevents the walls from freezing.
- A waterproofing layer protects the base from groundwater penetration.
- House heating costs are reduced.
Materials for thermal insulation of the foundation
Outdoor work requires special properties and characteristics from thermal insulation materials:
- moisture resistance;
- durability;
- low thermal conductivity;
- strength.
It is possible to insulate the foundation of the house from the outside with polystyrene, extruded polystyrene foam, polyurethane foam and expanded clay.
Polyfoam - the material is popular for thermal insulation of the foundation at the initial stage of construction and when facing the finished building. Among its advantages: durability, low cost, moisture resistance, high degree of thermal insulation. Plates are easily fixed using special glue, so the installation is easy to do with your own hands.
Extruded polystyrene foam does not absorb moisture and is not afraid of frost, it is used in any climate. It is stronger than polystyrene, does not crumble when cutting, and has a groove for tight joining. A 5 cm thick slab is sufficient to provide effective thermal insulation. Expanded polystyrene is durable, resistant to external stress, not afraid of rodents.
Polyurethane foam is a two-component sprayed compound with high thermal insulation qualities. It creates a monolithic surface without joints and cold bridges. To apply the mixture, special equipment is used. Excellent moisture resistance does not require additional waterproofing of the base. Polyurethane foam is applied to any type of surface and creates a protective barrier for 30 years. The composition decomposes under the influence of UV rays, therefore it must be protected from radiation. The lack of insulation is high cost.
Expanded clay is an inexpensive bulk insulation that has been used for a long time to insulate the base. With all the positive properties, the material is sensitive to moisture, therefore, careful waterproofing will be required. Unlike synthetic boards 5-10 cm thick, expanded clay is poured into a trench up to 50 cm wide.
Technology of external insulation with expanded polystyrene
- A trench is dug along the perimeter of the building to the depth of the base, its width is from 0.5 to 1 meter.
- The surface of the foundation is cleaned and inspected, the cracks found are covered with cement mortar.
- The base is being waterproofed. To do this, you can use penetrating insulation, bitumen mastic and weld-on roll coating. Liquid rubber is applied to the surface with a spatula, the roll material is heated by a torch and glued to the foundation.
- For thermal insulation, foam or polystyrene foam plates 5 cm thick are used. They are fixed on the waterproofing layer with mastic or polyurethane glue. Insulation must not be attached to hot bitumen or solvents used in the adhesive. In order not to damage the tightness of the layer that protects against moisture, the plates are not additionally fixed with plastic dowels.
- The first row of foam is laid from the corner of the house, the second and the next are mounted with an offset. The joints of the slabs are closed with polyurethane foam. The thickness of the insulation of the walls is twice the size of the material for the thermal insulation of the base, this forms a drip, which protects the foundation from precipitation.
- The outer part of expanded polystyrene is covered with a layer of roofing material and geotextile. You can finish it with the glue used for fixing and the reinforcing mesh recessed into it.
- After the end of the thermal insulation, sand is poured into the bottom of the trench with a layer of 15-20 cm and gravel up to 50 cm, and the excavated soil is poured to the top.
The described technology is the best option for thermal insulation of a strip foundation.
Installation of a blind area for soil insulation
To prevent freezing of the soil near the house, a formwork is installed for the installation of a concrete blind area with your own hands.
- A trench is dug 60 to 100 cm wide, 15-20 cm deep.
- A layer of sand of 10-15 cm is poured onto the bottom and rammed.
- Plates of expanded polystyrene are placed on top.
- The insulation is covered with a waterproofing sheet extending 15 cm onto the base.
- The surface of the film is covered with a metal reinforcing mesh.
- The plank formwork is installed with a slope, near the house its height is 8-10 cm, and drops to the edge up to 5 cm.
- Concrete is poured and leveled.
- The joint between the wall and the blind area is closed with a second layer of basement insulation.
Using expanded clay for thermal insulation
Bulk material insulation begins with earthworks. A trench is being prepared with a depth of at least 1 m and a width of up to 1.5 m. The base is waterproofed with bitumen mastic or liquid rubber. The surface of the trench is covered with plastic wrap or roofing felt, the ends of the canvas are brought up. Expanded clay is poured inside, insulation is wrapped on its surface. A concrete blind area is made on top of the trench, which has a slope from the wall to the edge.
Spraying polyurethane foam on the foundation
The synthetic composition is suitable for insulating any type of foundation: shallow, monolithic and tape. Polyurethane foam is applied to the surface in several layers until it reaches a thickness of 5 cm. When working with a toxic substance, a protective suit is required. Coating advantages:
- lack of joints;
- moisture resistance;
- strength;
- speed of application;
- durability.
The finished surface is treated with a special primer and plastered using a reinforcing mesh. After the finish has dried, the trench is covered with soil.
Insulation of a columnar foundation
The construction of the base in the form of pillars or piles leaves free space between the soil and the foundation. The implementation of thermal insulation in this case has its own characteristics, it is necessary to make a filling.
- A trench 30-40 cm deep is dug between the supports.
- A cushion of rubble and sand is poured one third of the height.
- Bars are attached to the posts, between which boards are packed. This is the pickup.
- Waterproofing and insulation are laid on the structure of boards and grillage. Decorative finishing is in progress.
- The lower part of the building is covered with expanded clay.
Comprehensive insulation of the foundation and soil enhances the effectiveness of external thermal insulation.
First steps:
- in the geological prospecting service, specify the depth of soil freezing in this region. The foundation is insulated up to this mark;
- choose a method of insulation: outside or inside;
- check the pros and cons of various insulation materials;
- carry out additional work before installing the thermal insulation layer from the outside of the building;
- the creation of taps will close the gaps between the foundation pillars and prevent various precipitation from getting inside;
- before arranging external thermal insulation, check if you need waterproofing of the base.
Insulation of the foundation outside
Most builders believe that thermal insulation from the outside is preferable to insulation from the inside of the base. Strong arguments:
- the heat-insulating layer on the outside retains the strength of the concrete;
- regardless of the type of foundation and insulation, the cold does not penetrate into the house;
- insulation outside the foundation provides reliable protection against moisture;
- temperature fluctuations are well "damped" by the outer heat-insulating layer.
Internal insulation of the foundation
This method is rarely used. The thermal insulation layer inside has more negative sides than advantages. Study them.
Advantages:
- thermal insulation inside protects the basement walls from condensation;
- the basement and the house will have a comfortable microclimate.
disadvantages much more serious:
- the foundation from the outside is defenseless against the effects of low temperatures;
- temperature drops and heaving of the soil quickly enough leads to deformation and the appearance of cracks in the base.
Materials for insulation of the foundation
Thermal insulation layer can be done from:
- penoplex;
- foam;
- polyurethane foam;
- extruded polystyrene foam.
When choosing a heater pay attention to the following characteristics:
- coefficient of thermal conductivity. The lower it is, the better the material retains heat;
- density. This factor affects the size of the load on the foundation;
- flammability of the material. High flammability class (G1) will provide reliable protection against fire;
- water absorption coefficient. The worse the material absorbs moisture, the less problems with dampness and mold on a damp substrate.
Do-it-yourself insulation of a columnar foundation
Have you decided to insulate the base yourself? How to insulate the columnar foundation yourself? To do this, follow the order of the following.
Note! The process of warming the foundation of a brick and wooden house is carried out using the same technology.
Pick-up device
The fence protects the foundation from atmospheric precipitation. It serves as a base. High-quality insulation of the fence will save the house from drafts, provide a good microclimate and the absence of dampness.
Procedure:
- dig a trench between the pillars 20 to 40 cm deep;
- add gravel and sand to 1/3;
- fix the beams with grooves for installing boards;
- with the vertical method of fastening the beams, one part is fastened in a trench, the other in the lower part of the house;
- when placing the bars horizontally, they are attached directly to the posts;
- insert boards 4 to 6 cm thick into the grooves of the beams and fix them well;
- sprinkle the finished filling with expanded clay from the inside;
- now you can proceed to the construction of the thermal insulation layer.
Polyfoam for warming the base
Any home craftsman can handle such work.:
- clean well the surface intended for insulation;
- close up all the cracks and eliminate irregularities;
- start work from the bottom up;
- apply suitable glue to the foam plates;
- glue the sheets to the base and fix with special plastic dowels;
- the next layer is a reinforcing mesh;
- further - putty;
- the last layer is a finishing putty.
Thermal insulation with extruded polystyrene foam
This material is often used for arranging an insulating layer. Expanded polystyrene prevents the appearance of dampness and the development of fungi. Keeps warm well. Sheets are easily mounted using a special adhesive.
Installation is carried out without much difficulty:
- the first layer is waterproofing;
- start attaching polystyrene foam plates from below, moving up;
- if the waterproofing is made of bituminous roll material, just heat the bitumen to 55 degrees, attach the plate and press well;
- with other types of waterproofing substrate, the insulation is attached with a special mastic. It is applied to polystyrene foam in strips;
- attach the slabs to the waterproofing and press down.
Thermal insulation of the foundation with polyurethane foam
A new word in construction practice. The material quickly gained popularity.
A durable, environmentally friendly, durable, fireproof polymer is applied from a special blowing machine. Just 5cm of polyurethane foam - and your foundation is well insulated. The undoubted advantage is the high speed of work.
If you can rent a blower - do the work yourself:
- clean the foundation from dust, debris, earth particles;
- apply insulation directly to the base. Foam will fill in all cracks and irregularities. No voids or air pockets;
- adhesion is excellent. The material sets quickly;
- the result is a high strength synthetic board.
Note! The material does not absorb moisture. For reliability, experts recommend additionally, on top of the insulation layer, to perform waterproofing from a water-repellent material: liquid rubber, polyurea and others.
If nothing works out with renting a machine for applying polyurethane foam, you will have to call specialists from a construction company.
Insulation of the foundation with penoplex
Penoplex is made using a special technology from extruded polystyrene foam. The material has excellent performance:
- one of the most heat-resistant polymers;
- durable;
- durable;
- safe for humans;
- installation is quick and easy;
- a wide range of polymer boards (thickness from 20 to 100 mm) allows you to choose the desired option and not overpay for an extra layer thickness.
Slab size: 60x240 and 60x120mm. There are three categories of insulation with different densities.
Note! The polymer is quite flammable. Perhaps this is its only drawback. A layer of fire retardant can be applied. At the same time, environmental indicators will decrease.
Procedure:
- cover the entire surface with special adhesive mastic: from the sole to the grillage;
- to the zero level, just press the plates against the wall;
- between the zero level and the grillage, additionally secure the penoplex with umbrella dowels;
- for fastening heat-resistant dowels, drill holes in the base;
- most of the panels fit well into the groove. Check all seams. To be sure, insulate them with polyurethane foam.
Insulate the columnar foundation according to the technology corresponding to each type of thermal insulation material. Qualitatively insulated base will serve as the basis for warmth and a comfortable microclimate throughout the house.
Foreword... How and how to insulate the columnar foundation of the house with your own hands? Do I need to insulate the columnar foundation of the bathhouse and the house? Correct insulation of foundation pillars will help preserve heat and protect the structure from early destruction. Consider in the article how to independently insulate the structure, what materials to use for thermal insulation, and also show a video on this topic at the end of the article.
The columnar foundation of a wooden house is used on difficult and heaving soils. The pillars are placed in the corners of the house and at the intersection of the internal walls, as well as along the perimeter of the building after 1.5-2.5 meters and below the depth of soil freezing on the site. The pillars usually rise above the ground by 0.25-1 meters. For the rigidity of the structure, a strip foundation is poured along the top of the pillars or strapping beams are placed.
Do I need to insulate the columnar foundation of the house
Photo. Diagram of a pillar foundation
If the columnar foundation of a wooden house is made of rubble or concrete, then after removing the formwork, the surface of the pillars is insulated with bitumen mastic in two layers. Instead of bitumen, you can use penetrating waterproofing penetron, which penetrates deeply into the micropores of concrete. It is also necessary to process and independently insulate the strip foundation or strapping beams from moisture rising from the ground.
Independent insulation of the columnar foundation of the house from the outside is carried out using extruded polystyrene foam (penoplex or technoplex). You can also use a cheaper but less durable board material - expanded polystyrene. In order to choose the right materials for thermal insulation, it is necessary to consider the most popular plate heaters, technical characteristics of polystyrene and polystyrene foam.
How to insulate the columnar foundation of the house outside
Photo. Insulation between the ground and the wall of the house
Styrofoam suitable for both external and internal insulation of the columnar foundation of a bathhouse and a house. Many developers choose polystyrene foam because of its low cost, but it is better to replace the foam with a more durable extruded polystyrene foam. Penoplex is a more expensive material, but it has high mechanical strength, thermal insulation boards are not afraid of high humidity and rodents, which is an advantage.
Penoplex, like other extruded styrenes (technoplex, ursa xps, etc.), they are characterized by high strength, low vapor permeability and durability. The insulation is produced in plates with a thickness of 20 to 100 mm, the material is resistant to moisture, microorganisms, insects and rodents do not start in it. Penoplex is used today not only for thermal insulation of the foundation, but also for insulating the blind area of \u200b\u200bthe house around the perimeter.
Mineral wool, like basalt wool, it is supplied in rolls and slabs of various thicknesses. Despite the low thermal conductivity of URSA mineral wool, like mineral thermal insulation from other manufacturers, it has high water absorption. The use of mineral wool as thermal insulation for house foundations is not recommended. You should carefully protect the material from moisture, find out which side to lay the vapor barrier on the mineral wool on our website, so as not to make a mistake when waterproofing.
Expanded clay is an inexpensive insulation for a columnar foundation and is already a time-tested material. Expanded clay for thermal insulation of the pillar foundation of a house or a bath is used by developers as follows: from the inside of the foundation, a formwork is erected from boards of 30-40 cm and expanded clay is poured into it. You can also fill the foundation inside the house with soil or the same expanded clay.
Scheme of warming the pillar foundation of the house
Independent thermal insulation of a columnar foundation with foam or technoplex is similar to thermal insulation inherent in a screw foundation, since the structures are largely similar. All work is carried out immediately after the waterproofing of the structure with the capture of the grillage (strapping beams) and part of the facade of the house by 25–0 cm. The pillars of the foundation are sheathed with bars and boards to full depth to create a frame for thermal insulation.
How to insulate a columnar foundation with your own hands
How to insulate the columnar foundation of a house outside? In order to insulate the columnar foundation with penoplex, the sheets are fixed with dowels or fixed to the glue for expanded polystyrene on the prepared lathing of the basement. Penoplex is durable, has high mechanical strength and retains its properties in wet soil. The seams between the thermal insulation plates are carefully sealed with polyurethane foam.
If there is no basement between the pillars of the foundation, then only the grillage is insulated (insulation of the wooden floor from below), and a moisture-resistant slab insulation is laid on the ground inside the house. This work can be done independently, for this, an insulated floor made of mineral wool is installed, a similar technology is used to insulate the floor in an apartment on the ground floor or in the basement of a private house.
Video. How to insulate a columnar foundation outside
Insulation of the columnar foundation provides for a number of additional work on the installation of barrage pickups, the purpose of which is to close the gaps between the posts and protect them from the effects of atmospheric precipitation.
Insulation of the foundation is an important component of foundation work. When constructing one or another type of foundation, this problem is solved in its own way and has its own initial data. Therefore, foundation insulation should be done in the most efficient and economical way.
Columnar foundation is a set of pillars dug in at all available corners of the building and in places of significant load under the load-bearing parts of the object. In order to ensure the coordinated functioning of the pillars as one structure and to increase their stability in order to prevent horizontal tilt and overturn and to support the basement, the pillars are connected with a grillage (randbeams, strapping beams).
For a complete vision of the picture, criteria should be considered that indicate that it is better to build a columnar foundation:
- buildings are being erected without basements, having walls with low weight (panel boards, frame, wooden);
- when a deep laying is needed (20-30 centimeters below the seasonal freezing of the soil, 1.6-2.0 meters) under the brick material of the walls and the device of the tape-type foundation is uneconomical;
- when the shrinkage of the foundation is much lower than this parameter for the strip;
- if the soils undergo significant changes under the influence of frost heaving forces: the pillars are less exposed to this effect than others.
Column foundation: device
Preparatory stage: clearing the construction area. The vegetation layer is cut off, a horizontal leveling of the site is made. Irregularities are removed, earth is poured into the pits. Evenness is checked using a level.
Breakdown of the territory for the foundation: the scheme is transferred from the drawings to nature by fixing the axes and dimensions of the object. Deepening the foundation from the zero mark of the house.
Digging holes for pillars (20-30 cm below the laying):
- holes up to 1 meter deep are dug with vertical walls and without fasteners;
- more than 1 meter deep - slopes are made on the walls, reinforced with boards and struts.
- Formwork installation. It is better to give preference to wooden materials than metal ones. This step can be omitted if the surface of the pits is dry and does not collapse.
- Installation of vertical reinforcement (d \u003d 10-12 mm) on poles with clamps.
- Concrete delivery and placement.
- Grillage device in the form of a monolithic or precast reinforced concrete rand.
- Installation of the pick-up.
Its purpose is to heat-insulate the space under the floor and protect it from dirt and debris.
Thermal insulation of a columnar foundation
It is possible to insulate the columnar foundation with the help of a pick-up and a number of other additional insulation works. A pick-up is a boundary wall located between the posts. It can be constructed from various materials: wooden planks, brick, stone. Each type of pick-up from a particular material should be described in more detail.
The degree of warmth and dryness of the floors in the house, its protection from winds will depend on how technologically correct the filling is performed.
Wood pick-up technology
There are several ways to insulate a columnar foundation using a pick-up made of wood:
- Installation of boards vertically.
- Placing boards in a horizontal direction.
- Making a pick from beams or logs.
It is possible to insulate the columnar foundation by installing the boards vertically in this way: in a trench 200-400 millimeters deep, dug between the pillars, fine gravel and sand are poured into about one third of it. A log with a groove is laid in a trench and a similar log is fixed to the grillage. In the grooves between the logs, boards are alternately inserted in an upright position.
To make a pick-up with horizontal placement of boards and insulate the columnar foundation, you need to: dig a trench between the pillars like the previous option. Fasten logs or beams with a groove to the posts. Boards (40-60 millimeters in thickness) are installed in the groove so that the very first lower board fits on the trench pad, and all other boards would fit on top of it.
On the inside, a wooden plank fence is sprinkled with expanded clay, and its insulation is performed.
To insulate the foundation with a log pick-up, logs are laid horizontally between the posts, as when building a house from logs.
You can also insulate the foundation with brick and masonry. If a pick-up is being built from such materials, then you need to dig a trench, which will serve as a sole for laying bricks or stones. The brick is laid on a concrete screed, secured with reinforcement. The thickness of the stone walls is made within 30 millimeters, the brick is placed in 1-1.5 pieces. In order to avoid the occurrence of cracks and gaps between the posts and the masonry, a strong adhesion is not necessary.
In buildings where high pillars are installed (from 0.7 meters), pickups are made of sheet insulation material. In order to insulate the foundation, a frame profile metal structure of the required section is first attached to the posts. Outside, sheets of corrugated board are suspended on it, and from the inside they are insulated with sheets of polystyrene (expanded polystyrene). The gap between the sheets of insulation and the soil is sprinkled with heat-insulating backing.
It is possible to insulate the finished structure of the filling under the foundation around the entire perimeter with plates of extruded polystyrene foam, which are attached outside the filling with special glue. In this case, the foam plates are tightly adjacent to each other so that there are no gaps between them. Penoplex insulation is considered the most effective method that does not require waterproofing. However, in order to ensure reliable protection of the basement from moisture, it is advisable to provide the foundation structure with a waterproofing coating.
The heat loss of a building through the floor can reach 20% and depends on how correctly the insulation of both the floor itself and the entire base of the house is performed. On normal soils, for the sake of economy, columnar foundations are often arranged. This type of foundation costs about 1.5-2 times cheaper than a strip foundation. With the correct calculations, such a foundation in terms of strength and reliability is not inferior to the strip, and sometimes even surpasses it.
Why insulate a columnar foundation?
Insulation of a columnar foundation has two goals. The first and foremost goal is to protect the foundation itself from thermodynamic destruction. The second is to reduce the total heat loss at home.
There is no universal formula for foundation insulation. In each case, the methods of insulation are selected individually. This is the work of a design architect. Therefore, this article does not provide step-by-step instructions for insulating a columnar foundation, but the main factors influencing the decision are called.
First of all, it is worth dwelling in more detail on the question: is insulation of a columnar foundation necessary at all? Surely there are builders who are inclined to believe that the foundation can not be insulated. However, when such an opinion is expressed, one should speak about what kind of foundation we are talking about, or rather, about the foundation of which house. If we are talking about it, then the answer is obvious.
So, back to our first question: why insulate a columnar foundation? When they talk about the insulation of a columnar foundation, they mean the insulation of the resulting underground space. If left unprotected, the ground under the building will freeze through. In a sheltered underground, even in the most severe winters, the soil temperature does not fall below 0 ° C. This has a beneficial effect not only on the energy efficiency of the cottage, but also on the foundation itself, because the soil at positive temperatures does not swell and does not squeeze out the columns.
By its design, the columnar foundation is very similar to the pile foundation. The only difference is in the depth of the supports. Piles are usually lowered to a great depth. The columns are installed on a sand cushion, which is located below the depth of soil freezing. There is a certain distance between the posts, as well as between the piles. Usually, the posts are laid at the corners and intersections of the walls, as well as in intermediate sections if the wall is heavy or long.
When the columnar foundation is ready and the builders move on to building the box at home, the need to fill the space between the columns is visible. A house without such filling looks unfinished. In addition, debris collects under it, the ground freezes, and the walking wind cools the floor, constantly carrying away heat.
Obviously, the insulation of the columnar foundation is simply necessary. Especially today, when energy efficiency is becoming the main condition for construction.
When it is worth doing the insulation of the columnar foundation
Insulation of a columnar foundation means both insulation using heat-insulating materials, and simple sealing of spans between the posts, i.e. pick-up device. In the overwhelming number of cases, a house on a columnar foundation also has a pick-up. It is performed in different ways, depending on the material of the posts; their heights above the ground; from architectural preferences, after all.
An example of a pick-up device.
Unfortunately, it should be noted that a modern energy efficient house cannot be built on a columnar foundation. Such houses are placed on monolithic slabs, completely insulated from the ground with a thick layer of rigid insulation. All other types of foundations (including columnar) assume so-called cold bridges. If there was a technical possibility to establish an effective thermal break between the support and the wall, then the columnar foundation would be one of the most economical and energy efficient at the same time. However, none of the existing insulation materials today is able to withstand concentrated compressive loads, such a force that the weight of a building exerts.
Now let's make a small but important digression regarding the financial side. It is not possible to reduce the construction cost estimate and increase the energy efficiency of the building at the same time. These articles are exactly the opposite in essence. Theoretically, it is possible to insulate all the building envelopes with such high quality that several hundred watts are enough for heating. But will there be any material benefit from this? Insulation also costs money. In addition, it has its own service life. If the payback period of insulation is equal to the period of its operation, then such insulation cannot be called cost-effective. Warming is considered advisable if it pays for itself at least half the time allotted to it.
However, there is another opinion. Some experts consider insulation as an investment project. It is believed that young and energetic people have the opportunity to spend money on serious insulation, and this will insure them against serious operating costs in old age, when they can no longer earn much.
Economists would consider this not the most profitable investment, because funds can be deposited in a bank, and the interest will probably be enough to pay energy bills. Moreover, this will already be the so-called compound interest.
If you put $ 1000 in the bank at 10% per annum, then in 20 years your account will have $ 6727. This is taking into account the fact that interest on the deposit will be charged on interest and with the condition that the deposit will not be withdrawn. And that's only a thousand. And when insulating a house with a layer of 10-15 cm, ten thousand may be needed. Accordingly, with the contribution of such an amount, the profit will increase by an order of magnitude.
In general, you need to count everything. True, there is one unknown in this problem - the cost of energy resources in the future. In addition, money depreciates, life rises in price, there is no stability. So people come to the conclusion that it is better to warm up now than to pay fabulous bills all their lives and heat the atmosphere at the same time for their hard-earned money.
How to insulate a columnar foundation
We return to the main topic. Hardly anyone today would consider it a good idea to leave the columnar foundation completely open. Typically, a cold pick is performed as a minimum.
Zabirka Is a fence that fills the gap between the corner supports of the columnar foundation. The building codes describe in sufficient detail the design of the pick-up. In this case, first of all, SNiP 2.02.01-83 are guided.
Various building materials are used for the construction of the intake. It can be brick, stone, cinder blocks, boards or beams, sheet materials (plywood, OSB). It is not recommended to use aerated concrete blocks and other materials with high water absorption for the construction of a pick-up. It is not difficult to guess why: the intake is subject to moisture (capillary, rain / snow). Since the pick-up does not bear any loads, except from itself, there are no requirements for the strength of its material. The pick-up can be made from lightweight large-format ceramic blocks. Such a filling will be both strong and heat-insulating at the same time.
Brick filling. Often, the fence is built of brick or stone. In this case, it requires a solid foundation underneath. Under a wooden house, the fence is buried 20-30 cm into the ground. It is recommended to do this, first of all, if the house is built on heaving soils. Narrow trenches are dug under the filling, at the bottom of which it is necessary to pour screed on a sand cushion.
Sometimes a stone pick is erected directly on a sand cushion. But it will still be more correct on the screed, since it evenly distributes the load from the masonry. The screed in this case is a guarantee that the masonry of the pickup will not crack under its own weight.
Insulation of the fence and blind area. Now let's talk about whether it is worthwhile to additionally insulate the pick-up. The most reputable experts strongly recommend doing this. Insulation of a columnar foundation, together with a filling, is relatively inexpensive, but it provides many advantages. The insulated foundation guarantees a positive underground temperature; in addition, the insulated columns themselves will not freeze. If you also insulate the blind area, then the posts can be laid not at the depth of freezing of the soil, but half as small. This will force you to spend a little on insulation, but will save money on earthworks and on the building material itself.
It is most correct to insulate the columnar foundation outsideso that the posts themselves and the pick-up are isolated from the cold. Warming should be done with a continuous contour without gaps. Since both the foundation and the filling are in contact with the ground and are subject to humidification by capillary moisture and atmospheric precipitation, you should choose materials with zero water absorption... These include extruded polystyrene foam, foam glass, polypropylene foam and other closed-cell polymer insulation.
Insulation of the columnar foundation with polystyrene with decorative paneling. The best option for both quality and cost is, perhaps, extruded polystyrene foam (EPS). Unlike conventional foam, EPPS does not absorb moisture and therefore does not accumulate it. Ordinary (non-extruded) polystyrene foam has significant water absorption, so it is not the best material for insulating a basement and even more so a foundation. If you have a question about choosing a heater, article materials can help:.
After the construction of the pick-up, the columnar foundation looks like a strip foundation. Accordingly, the issue of ventilation of the internal space becomes. As in the case of the strip foundation, you will need fumes... If the intake is constructed of brick or stone, then the air vents are left in the form of passes.
To protect against rodents and birds, the air vents are covered with metal nets. Air vents should be placed on each side of the base of the house. It is more convenient to make square vents in brickwork. The recommended size is 10-15 cm. The products are distributed so that they are opposite each other. Their meaning is that the wind blows fresh air into the underground from whatever side it blows. Then "excess" air will come out from the rest of the vents. Thus, the ventilation of the underground space is carried out.
Conventional columnar foundations do not have a grillage in its technical sense. The withdrawal is laid only on the outer circuit. Inside the perimeter of the house, the columns are not connected with solid walls, so there is no need to make internal air vents, as is the case with a tape-type foundation.
The number of vents theoretically depends on the volume of the underground. If the height of the column above the ground is within 30-40 cm, then one vent is enough for 3-4 m horizontally. These numbers are taken from practice and are most likely correct. If you make too many vents or their cross section is too large, then the underground begins to overcool. At the same time, no matter how many airs are made (within reason), the soil under the house will still not freeze. But everything needs a measure.
Lack of air is also bad. The soil contains moisture, and it ends up in the insulated underground. There is not too much trouble in this, especially if the posts and the filling are made of high grade concrete. However, moisture is always the enemy of any design. Reinforcement in reinforced concrete posts is highly corrosive from moisture. The rust expands and literally tears apart the concrete. And weakening the support of a building is an unpleasant thing.
Finally. Guided by the considerations expressed in this article, you can independently make decisions when developing insulation for a columnar foundation. Understanding the principle of basement insulation, knowledge of heat-insulating materials and makes it possible to find, based on building standards, the optimal way of thermal insulation.