Monolithic slab foundation

Foundations in the form of reinforced concrete slabs

When choosing a foundation guided firstly, reliability, second value. It would be nice if you would combine both qualities, but it is not always possible. One of the most reliable basis for the construction of the house - the foundation of a monolithic slab. In some cases - on normal soils under the light house it is relatively inexpensive, can be expensive in complex cases.

Monolithic slab under the house refers to the unburied floating foundations, it is also shallow. Its name was due to the fact that the iron-concrete foundation is poured under the whole area of ​​the house, forming a large plate.

An obligatory condition is the presence of sand-gravel cushion that distributes the load from the house to the ground, and serves as a shock absorber when frost heave. Often, such a foundation - the only possible solution. For example, for unstable, loose soils or clays with a large depth of freezing.

Classical insulated slab foundation under the house

foundation design is a monolithic slab simple and reliable, but its production requires a large number of fittings and large volumes of high-grade concrete (at least B30), in fact reinforced and concreted the whole area occupied by the building, so even with the stock - for greater stability. Because such a foundation is considered to be expensive. In principle, it is true, but should be considered. In some cases, it costs less than a belt deep foundations - due to the smaller volume of ground works and less concrete.

Depth of the monolithic plate is determined by the weight of the house and the type of soil. For a small burial on heaving soils in the winter house together with the base can be raised and lowered. When properly based reinforcement plate thickness and the integrity of the building is not affected. Plate compensates for any change due to the elastic force. In the spring, after the ground has melted, the house "sit" on the spot.

There are four types of plate foundation:

  • Classical. Concrete slab settles on sandy-gravel cushion with or without insulation. The thickness of the layer of concrete of 20-50 cm, depending on soil and building weight. The thickness of the cushion layer depends on the depth of topsoil - it must be completely removed. The resultant pit 2/3 can be filled with sand and gravel.

Classical variant monolithic slab foundation without insulation

UWB - insulated Swedish stove with built-in underfloor heating

It looks like in the context of Russian slab foundation

The structure of the foundation plate with ribs up and down

construction insulated plates Technology

Saving energy is becoming really a hot topic, so that the foundation without insulation are few who builds. Any slab foundation - a multi-layer structure, and in the case of the insulation layer even more. To achieve the desired level of quality need to be followed carefully to each of the levels. Let us examine each in more detail.

monolithic slab foundation structure

The dimensions of the pit under the monolithic slab must be greater than the building itself, at least 1 meter. On this site completely removed fertile soil. Its thickness varies in different regions - from 20-30 cm up to 50 cm and more. In any case, all clean.

Dig a trench with a margin of 1 meter in all directions

Along the edge of the pit, below the general level of the bottom, drainage pipes are laid, the outlet surface water drainage wells. This measure is necessary to make the walls and the very foundation of not soaking.

Full diagram monolithic slab foundation

The bottom of the dub, the pit is filled, the humps are cleaned thoroughly in all dub horizon level and compacted. At the bottom of the lined rolled geotextiles. He must cover not only floor, but the walls. Cloths are spread with overlapping edges are glued with reinforced tape. Geotextile prevents the roots of plants grow, and prevents washing away of sand, which serves as a damper pad.

Alignment in the bottom level

Laid on geotextile poured clean sand medium grain. A layer of sand -. 20-30 cm His poured in thin layers, and spread evenly in layers ram. A layer of sand, which can be qualitatively ram manual vibratory plates -. 8-10 cm Here those layers and stack sand. It should also be laid at the level of the same layer around the pit.

The sand is poured, it must be shed and ram

The layer thickness can be controlled by means of tensioned cords. They were tied to stakes driven into specially made supports - benches, to set at the level of the formwork (see the photo below). All cords should be located in a horizontal plane. Knowing the original distance from the bottom of the pit before the stretched filaments can be determined by the height of the poured layer.

On hard-packed sand poured rubble. Fall asleep once the whole volume uniformly distributed over the area. Aligned rubble ram to a high density.

Rubble filled, set mortgages elements of sewerage and water supply

In this step, laying sewer and water pipe. In the already compacted gravel dig ditches desired depth. They must be such that some space has been around for mortgages elements. In ditches stacked pipes, filled with sand, are aligned, shovel or board compacted sand. More serious compaction can lead to cracks. Because the pipe already laid and tamped.

Along the perimeter of the pit put formwork. It is collected generally from 40 mm thick boards or plywood 18-21 mm. The height of the formwork for monolithic plate - the total thickness of the remaining layers. On its edge is convenient to control the level of concrete when pouring, for the board to be cut. To save material, it is possible to set the formwork only for training. After setting concrete dismantle it and put above using the re-pouring the base plate. But the loss of time with such an approach are considerable, so so do not always.

In any case, the formwork props from the outside and stops struts. The structure must be rigid to withstand the weight of the concrete.

Compacted gravel is poured on 100 mm of concrete layer. This may be a low concrete stamps - B7.5 - B10. Concrete training will be a solid basis for laying of waterproofing and insulation, it is also used for a more uniform load distribution from the house.

Poured concrete preparation

Since the monolithic slab foundation is completely in the ground, it needs to be carefully waterproofing. Because usually use two types of materials: obmazochnuyu and roll. Base first carefully dedusted and then impregnated with diluted kerosene or solvent primer (and the sides of the concrete preparation also promazyvayut). Sale it is very dense and poorly grasped with concrete. As a result, the roll bonded waterproofing the foundation is bad and will get wet. Divorced, he becomes more fluid and penetrates deeper into the concrete. Their properties at the same time almost does not lose.

When the layout of the roll of waterproofing, it released outside basement of 10-15 cm. The panels roll out overlapping, connecting edges necessarily coat with mastic asphalt and well-pressed. When the layout is necessary to ensure that there was no wrinkles and waves.

If the groundwater level is high, it may need two coats of waterproofing roll. It then rolled across, and also glue on the primer (bituminous waterproofing), but you can not breed.

Waterproofing of monolithic slab foundation double - Obmazochnaya and roll

Of roll waterproofing materials is best proved effective waterproofing, Technonikol Technoelast EPP -4 to high-density polystyrene. In this brand Tehnolnikolya high tensile strength of about 60 kg, which increases the chances that it will not damage during subsequent works. Use roofing felt like it would be desirable to save, you should not. In today's performance he is too thin and brittle, quickly loses its properties. Replace the waterproofing of the plate, you can not, because overfill the best material.

Reduce the capillary suction of moisture from the slab can still use the liquid impregnation type bentonites. She at times reduces the absorption of moisture. Penetrates to a depth of 50-60 cm, so that the concrete preparation soaks through. Disadvantage of this material - the high price, but the properties have excellent material.

For insulation slab foundation using high density extruded polystyrene. The thickness of the insulation layer - 10-15 cm, depending on the region (the middle band is enough for 10 cm). Stacking is carried out in at least two layers, overlapping seams which form cold bridges. Time it takes longer, but heating costs will be lower. If the plate will have L-shaped lock, they can be placed in a single layer.

Since polystyrene "not friendly" with oil, it spread a thick plastic film, and then placed heat-insulating material.

For reinforcing the frame used ribbed rebar class AIII, diameter of 12-14 mm. She laid up and down, in increments of 15-30 cm, may have one or two layers. It all depends on the type of soil and building mass. All parameters of reinforcement are considered separately.

From armature plate edges it should be located at least 5 cm. Because it is laid on special supports, which provide the required clearance.

The first row of connected reinforcement, exhibited some racks for tying the second belt

When reinforcing the cell obtained in each point of intersection between the rods connect a special soft steel wire. There are Connection technology - using plastic fasteners or welding. Plastic straps to bind fast, but not all of them trust. Welding is not recommended, because the weld - the most vulnerable to rust spot, and too rigid connection is obtained. When using the wire clamps and the entire structure can be a little "play" without destroying the bunch, and when welding such shifts lead to the fact that the joint breaks. As a result, the reliability of such a reinforcement is low.

Pouring concrete foundation slab

Plate thickness is calculated for each specific case and may be from 20 cm to 50 cm. When pouring concrete is used below grade B30. The entire perimeter of the need to fill in a day, avoiding the appearance of vertical joints. Because the foundation slab concreting often bring concrete ready: requires large volumes in a specified period.

Along with the distribution of its concrete vibrated

Schedule cars arrival should be calculated so that you have time to distribute a first portion and seal it. To seal construction using vibrators that generate high-frequency oscillations. all the air removed a result, the concrete is mixed better, it becomes more fluid and malleable. The result of this treatment - not only the smooth concrete surface, but also a higher class of hygroscopicity.

In a pinch, you can pour the slab in horizontal layers. Vertical division in this case is unacceptable, because the joint areas most likely will crack.

For normal concrete curing process, a sufficient level of humidity of 90-100% and temperatures above + 5 ° C. Pour plate preferably in warm weather, with a temperature of about + 20 ° C. This temperature range is optimum for the hardening process. Curing monolithic plate is to prevent mechanical damage and maintain humidity.

Immediately after the laying of the concrete cover or diaper covers. It does not give him warm from the sun, it is not the wind effect. The film is glued to the big cloth. The strips are placed with stops 10-15 cm, glued tape. It is advisable to neproklennyh joints as small as possible, ie a shelter should consist of one or two pieces, if one is too inconvenient. The individual pieces of film come to one another by at least half a meter.

Poslezalivki monolithic slab hiding film

The dimensions of the film such that has been closed and the side surface of the casing, and on the edges of the film could put the goods that will not raise its wind. Also load - doskami- place prehlesta two pressed webs to reduce windage, they can be decomposed on the surface.

If the air temperature is higher than + 5 ° C, after about 8 hours after pouring, the concrete first watered. Irrigation should be drip, not a jet. To avoid damaging the surface of the droplets, it is possible to lay the burlap or pour a layer of sawdust, and close the top film. Water the covering material, and it supports concrete humidity. In any case lead watering only at temperatures above + 5 ° C.

If there is a danger of frost, the slab formwork and additionally insulated. Can use any heat-insulating materials are prepared to build a house, and sawdust, straw and other available means.

For monolithic plate recommended to remove the formwork after the concrete attains 70% of the design strength. This period depends on the temperature, in which the hardening. This dependence is shown in the table.

Table set concrete strength as a function of temperature

Differences insulated monolithic Swedish stove and a video of its construction

As previously discussed, developed by Swedish builders insulated slab under the house is enegosberegayuschey. When its construction using permanent formwork of expanded polystyrene. As a result, the heat leakage into the soil is minimal. The second fundamental difference - built in in the slab system of water underfloor heating.

Since the engineering systems are embedded in the concrete is thicker, it requires a precise and competent calculation. High demands are made for execution. Even small errors are critical. UWB do you can do it yourself, but the project is better to order. The approximate balance of cost, see the next photo. Amounts may already be outdated, but the percentage is valid. the foundation of the project cost is about 1%.

The approximate percentages for monolithic slab foundation costs

In the following video you will see the stages of manufacture of the Swedish stove for a specific house. Described many useful tools that will facilitate the work, are given an explanation of some features.

And look at how such a plate is filled by Germans. Too many useful nuances.

Step by Step Guide for the Development of a monolithic foundation

To build a new house with his own hands is not developed into a major overhaul a few years, you need to take care of the right foundation. It is required not only to withstand the weight of construction - this is usually a problem does not arise. It is much more difficult to offset the impact of excessive mobility of soil on the wall. On difficult areas with poor soil with this task can handle only a monolithic slab foundation.

When you do not do without a stove?

In fact it is just a reinforced concrete "cushion", on which the house stands. With a maximum bearing surface on the structure of the load is transferred to the ground already in a distributed fashion, and the pressure is reduced by several times. And the wider will be "contact patch" on the circuit, so it is below. This property allows the use of slab foundation where construction weight exceeds bearing capacity of the soil.

Another case when you do not do without a solid foundation - heaving soils (sands, sandy loams, all types of clay). This may also include wetlands and flooded areas. Use of this site on a monolithic tape will lead to the fact that one part of the house in the season will be raised, the other lowered, and load-bearing walls will just work on the gap. And if a tree like elastic load is still capable to endure, the brick or block construction of such treatment quickly go cracks.

Output - the same monolithic slab. Remember the picture of the physics textbook, where a matchbox bobs on the waves, but does not move? The same principle will work and flat foundation. Soil can raise or lower it, and the house will remain stationary relative to the concrete surface.

These are two exceptional cases, when the use of monolithic foundations economically justified. In any other situation from it should be abandoned in favor of cheaper metal piles or concrete strips. However, it is only a question of money - there are no other restrictions. Price turnkey foundation even a small thickness of 25 cm starting from 3600 RUR / m 2, more powerful pull plate already 4000-5200. Even the device monolithic foundation with his own hands will only half the price as the main item of expenditure - this is the purchase and delivery of building materials. And they just need a lot.

Phased construction of technology

If the site just fell under the definition of exceptions or builder does not feel so sorry for the money as its own forces, it's time to get acquainted with monolithic technology and study guide for the plate device. Step by step guide divides the construction of the basement in separate stages. Each step - a new layer of a kind of "pie", and one can not miss any. The work has traditionally begin with the markup, preparing and leveling the pit. It will gradually be laid and construction materials. Usually, melkozaglublenny slab foundation layer is sufficient to remove the fertile soil and digging a flat platform at a depth of 0.5 to 0.7 m.

Next order of work will be:

1. Device drainage cushion.

A first layer of poured sand is moistened and tamp it to obtain a flat surface. Depending on the weight of the future building (taking into account the very foundation plates) the thickness of the finished cushion is chosen from 20 to 30 cm. Top trail geotextiles and make repeated dumping at a height of 20 cm, but from the rubble.

At this stage it is possible to perform the preparation of liquid concrete brand M100 solution. In the presence of gravel cushion the item is optional, although casting cost is low, but the benefits are many. The thickness of the protective concrete layer is 1 cm, but provides greater stability of the foundation on the ground, and better protect it from excessive moisture. At this stage one can take care of the thermal insulation of the base and partially monolithic implement Swedish plate technology. For this purpose, the entire area is formed by a continuous cushion of high density foam or polystyrene. But, again, all at the discretion of the owner.

2. Waterproofing basement.

The most inexpensive and an important stage of the work, after which a monolithic slab becomes "immune" to the destructive influence of moisture. After unburied base in any case would be above the level of soil freezing, and soaked in the winter the water starts to break it from the inside. Unavailability of concrete water will ensure its long life.

Instructions waterproofing of the foundation recommended that you start with the top of the geotextile drainage. Its advantage is sometimes called the impermeability of the cement milk, but that it has reached the gravel layer, the plate would have to pour water from a hose.

In fact, the dense membrane is a thin insulation protects against damage. On geotextile is laid in two layers n / e film thickness of 0.2 mm and solder joints double seam. Sometimes as Gidrobarer used roofing material, but its life is not large enough - 10 years from now it will rot, and will not be replaced. Insulation is taken of such a width that at the end of the slab foundation work could wrap it with the ends. This creates for seamless waterproof layer which protects against moisture the concrete and the subsequent destruction of the arrival of frost.

3. Installation of the formwork and frame.

Slab foundation has a small height - from 15 to 40 cm, so that the deck boards will usually suffice. The main thing - good to strengthen them by placing side mowing and struts, as well as to check the parallelism of the opposite wall. Fittings fit two horizontal belts with transverse dressings. The size of cells is selected from 200 to 300 mm - this scheme reinforcement monolithic foundation slab is considered optimal in terms of strength, though it requires a large flow rate and the binding wire rods. The distance from the ends of the rods to the outer monolith wall should be about 50 mm. This will provide protection against metal corrosion in the body of the concrete.

If the planned foundation reinforcement fiberglass reinforcement, the difference can be reduced by half, as the composite is not afraid of moisture. Otherwise diagram stacking bars remains unchanged. Such a replacement of traditional metal is performed smaller diameter rods and provides a good cost savings, the carcass strength is maintained. Plus - tear resistance in fiberglass reinforcement is much higher than in the same AIII.

4. Laying of concrete.

The entire volume of the foundation formwork must be poured in one go. Hand is the amount of solution will be difficult to cook, so it is easier to order its delivery to the nearest RBU. Mark concrete selected based on the strength calculation, but usually lack the M250-M350. The main thing is to mix mobility was sufficient - class A3 or higher, if the work is done in hot weather.

: Fresh monolithic slab is compacted and leveled or smoothed vibrator wide rule. The quality of the concrete surface at this stage is of paramount importance, since stiffen solution difficult to process. Better just to do it right than to grind the cement stone. Plate covered with foil, but after a day it is necessary to moisten. In general, concrete works, it is desirable to arrive just crude and cloudy weather to hydration proceeded normally.

According monolith technology should gain strength 4 weeks, but the stripping of the foundation can be made earlier. To continue the construction of the concrete is enough for 70% of the declared brand - it will reach them on the second week. So wait for the full term is optional. After removal of the left edge of the waterproofing lifted from the ground and are soldered to the board ends.

The technology of monolithic base unit is really very simple and does not require the builders of a great experience. That is why it is often chosen by those who have to manage on their own. After all, in compliance with the instructions serious errors are virtually eliminated, as the costs at first one does not count.

But the construction of the monolith can be, and sometimes need to save. To do this calculation foundation slab thickness under construction scheme. Monolith must be sufficiently strong to resist bending loads on the walls in between. Partially "lever arm" can be reduced by forming on a plate of ribs.

At the same time the foundation is too thick will not only material-intensive and expensive, but also increase the pressure on the ground due to its weight. So it is worth to spend half an hour to figure the design technology w / w-plates.

When using the option pile foundation is necessary to solve the problem of floor insulation.

Preparation for any type of construction is not complete without a preliminary calculation.

Of great interest to the foam concrete is caused by its properties: light weight, perhaps.

What better foam or aerated concrete?

Application of DSP in construction

Varieties monolithic foundation + example of the construction of a reinforced concrete slab with his own hands

With all the modern variety of types of foundations and their advantages, many builders prefer baths still monolithic. After all, what one piece, always stronger than prefabricated. Yes, and the process of construction in this case, something easier. And the most popular foundation - a monolithic slab, which is so secure that even build skyscrapers on it.

What good is this type of foundation?

Monolithic foundation is always strong and can withstand heavy loads. They are not afraid of any irregular movement of the ground, nor the constant rainfall, no hard freezing and thawing. Bath will simply rise and fall with the foundation, without destroying any supports. It is known that concrete works only on the compression - and not to expand. That is why the foundation in the form of a monolithic slab is practically irreplaceable for heaving and sandy soils where the groundwater level is high.

Yes, lumber, frame and log saunas such a foundation, in some cases, and luxury - if the ground is normal, it is easier to make a tape of a shallow inception. Here are just a Russian sauna itself has long ceased to be just a hut - in fashion their own overall bath complex with swimming pool and billiard whole. And under the massive slab pair solid foundation - that is necessary.

Varieties monolithic foundation structures

In a monolithic foundation has several species. The most popular - this slab, which is also divided into a slab and plate on a tape similar to an inverted cup, which every day becomes more and more popular abroad.

But in terms of the construction of the bath while the best has proved to be just such a device is a monolithic foundation - a monolithic slab simple scheme. Its main advantage is that there is no need to put it below the freezing depth of soil - and it is a significant reduction in construction materials costs and reliability with sharp drops in air temperature.

Monolithic foundation slab inherently is a continuous reinforced concrete slab, which is recessed into the ground. And external and internal walls of the bath are built directly on this plate. And thanks to the uniform distribution of the load on the entire area of ​​the plate pressure on the ground is minimized - here works the same physical law, when a man in boots in the snow falls, and the skiing is not because of pressure area longer. plate design is so universal, that is even suitable for frank peatlands and even swamps. And most importantly - in the construction of such a foundation are virtually eliminated any errors, but because the private construction it fits perfectly. Including - for the bath, because the volume of excavation in this area is minimal, and the ground floor steam is not particularly needed.

Another type of monolithic foundation - a columnar monolith, which is being built for light baths. In fact, it is a unitary construction of raft foundation, and reported them to the pillars.

But belt solid foundation with a basement can withstand fairly heavy loads and feels good in the most adverse climatic conditions due to the fact that copes with subsidence, thawing and ground vibrations. In fact, it reinforced concrete strip that runs around the perimeter of the building. It can be melkozaglublennoy and recessed. The first option is suitable for bath from logs and timber, but the second - for a brick two-storey twin, have considerable weight.

Stages of construction reinforced concrete slab

The process of construction of a monolithic foundation is much more straightforward than the construction teams. But there is an important point: all the materials used must be of the highest quality, as a solid foundation to satisfy more severe requirements. But we should not at the same time attracting the construction machinery!

The first step is to clear the well site: to remove the top layer of soil with vegetation, which can employ a bulldozer.

The thickness of the foundation, or rather, it is a monolithic plate, can vary from 15 to 40 cm. It depends on the characteristics of the ground, the weight of future bath and what it will be filled.

Normally, such a foundation pit for dug to a depth of 1.5 meters, pulled out and replaced with a clay gravel or sand. Leveling the surface should be on building level - about any biases and speech can not be, otherwise deformation and complete destruction of the foundation of the future can not be avoided.

Sometimes these foundations are built from ready-monolithic reinforced concrete slabs, which can be seen at the time of construction in the panel house. They have clearly calculated quality, but their installation will have to call the crane and still do all concreted over screed. And such a design would not have such a tight, as absolutely monolithic slab.

And for the construction of their own hands initially need formwork. For thick boards it will need at least 25 mm plus the cut. Formwork itself is necessary to put a Walkers - and it is desirable initially to test the stiffness of the whole structure. It is possible to make basic kick - if the casing breaks down, it is better at this stage, rather than during the concreting.

Step IV. Warming and waterproofing

So, then constructed drainage system. Put waterproofing and, if necessary, warming.

Here it is worth mentioning the Swedish construction technology such a foundation - it involves the use of modern thermal and waterproofing materials. It is meant a base of the insulated plate which has a tremendous energy saving properties at low construction time and low cost. For Russian baths - the most it!

The next step is mounted fittings. Sometimes special mesh further secure the underfloor heating system.

Fitting best to take 16 mm - in the extreme case it is possible, of course, 14 mm. But calculate it is not so easy - it is better to do it in advance.

Stack valves need to criss-cross, in two rows. Thus are obtained two mesh - a bottom, 5 cm from the surface of the sand bags, and the second - from above, is 5 cm from the surface of the base plate. Between the bars in the grid should have exactly 20 cm. Knit reinforcement need ordinary steel wire.

Pour concrete in such a foundation is necessary at once, and he should be only high-end strength - from the M300 for the brand, with a waterproof factor of more than W8 and frost resistance of F200 and index A3 mobility. There is an important point - all the materials used must be of the highest quality, as a solid foundation to satisfy more severe requirements. Just go away somewhere at least 20 cubic meters of concrete.

Once the plate is dry, concrete floors in the bath will be fully ready for finishing. What is the biggest plus and monolithic foundation - a minimum of hassle, maximum results!

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