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The comfort of being in the garage largely depends on whether the floor is made correctly. It must be durable, reliable, moisture resistant. Not many materials meet these requirements. One of the most common is the concrete floor in the garage. In order for it to perform its functions, it must be done correctly. How – in detail, we will describe step by step in this article.
Substrate preparation
The concrete floor in the garage is done on the ground. But most often the soil itself is not a sufficiently reliable and dense base, therefore a base device is required – cushions of crushed stone and sand. Preliminary and mandatory work is the removal of the fertile layer, up to clean soil. With a fertile layer, organic matter and most of the microorganisms are removed, and in clean soil they contain a minimum amount.
Zero mark
As a result, you get a pit of some depth. Crushed stone and sand will be poured into it, but in order to understand whether its depth is sufficient or excessive, it is necessary to determine the “zero” level of the floor. It is convenient if the floor is flush with the threshold of the gate. Often they make it just below the threshold, but then you will have to somehow drain the water, and it will definitely be, if not in spring-autumn, in winter, from melted snow, for sure.
Mark the zero level of the floor along the perimeter of the walls. The most convenient way to do this is with a plane builder (electronic level or level). Turn on the device to display the horizontal plane, set it at the desired level and draw along the beam.
If there is no laser level, use the water level. It is not so convenient with him: you have to transfer the mark many times along all four walls. These marks are connected by a straight line, instead of a ruler, you can use a bubble level, at the same time you can check whether all the marks have been set correctly.
Calculation of the thickness of the PGM layers
As a result of these works, we have a foundation pit and a zero floor mark. Now you can calculate how thick the layers are needed to reach the desired height. It is necessary to proceed from the following dimensions:
- the optimal thickness of the concrete floor in the garage (if there is a car or lighter transport) – 10 cm;
- the minimum thickness of the crushed stone layer is 10 cm;
- sand – not less than 5 cm;
In total, it turns out that the pit should be no smaller than 25 cm deep. And that doesn’t include flooring. If you simply impregnate or paint the concrete floor, then no additional centimeters are required; for any other coating, add the required thickness.
Having received a specific figure, you can plan the amount of sand and gravel. If the layers turn out to be very large, you can fill up the bottom and compact the soil (but not the fertile layer). If the depth of the pit is not enough, we take out some more rock.
On the walls of the garage, marks can be applied by which it will be possible to control the thickness of the layers. With a small garage width – 2 meters or so – these marks are enough. If the garage is wider, you need to set up a few more stakes in the middle and mark them too. Of course, all marks must lie in the same plane. This is again conveniently done with a level. Another way is to take a flat bar or board, attach it to the marked marks. Put a level on top of the bar / board. If everything is set correctly, the bubble will be in the middle.
If you plan to make a hole in the garage, it’s time to dig a pit under it. If the pit is with brick walls, you can immediately pour a concrete floor into it. While you are engaged in backfilling under concrete in the garage, it will gain the required margin of safety and it will be possible to lay out the walls. They can be driven out after backfilling pillows of crushed stone and sand on the floor.
Bedding materials
For a normal concrete floor in the garage, it is better to take not gravel, but crushed stone. Gravel, with its rounded edges, you will never compact to the required degree. And if the base under the concrete is unstable, even a thick reinforced slab will burst. Therefore, we import crushed stone, medium and small fractions. Medium 60-70%, the rest – small.
There are no special requirements for the quality of sand for pillows. It is important that it be free of clay inclusions, but it can (and should) be sieved before laying.
Making a pillow under the concrete floor
The first step is to level the bottom of the pit. We remove irregularities, fill in the hollows, bring the level to the horizon. Do not think that the concrete floor in the garage can be done with violations. You can do it, but then the plate will crack, you will have to redo it.
Now we take a vibrating platform (you can rent it) or a manual rammer and compact the soil. Along the way, once again leveling the plane. When the soil is compacted, crushed stone can be poured. Do not fall asleep the entire volume at once – 10 cm is not normally tamped. The maximum layer is 5 cm, but 3-4 is better. We fall asleep the necessary part, distribute, level (with a rake) achieving approximately the same thickness. We take a rammer or vibrating plate and ram.
This crushed stone rammer is very important when constructing a concrete floor in a garage – a certain amount of crushed stone is driven into the ground. As a result, it becomes even more dense, the bearing capacity increases, and the possibility of subsidence is excluded. Tampering is considered sufficient if you step on the surface without leaving any traces. In the same way, all portions of crushed stone are rammed, bringing to the required thickness.
Sand is poured onto the compacted gravel. It is also divided into parts of 2-3 cm. The peculiarity of tamping sand: it must be moistened, they also say – shed. Wet sand is rammed, again focusing on the layers.
Now you can start forcing the walls of the pit, if any. They are brought to the level with the finished floor or even a little higher – so that you can wash the car right in the garage without fear that water will get into it.
damper clearance
A concrete floor on the ground is often referred to as “floating”. This is because it is made incoherent with the walls of the building. In this case, the walls and floor can sag or rise independently of each other, while maintaining integrity.
So that the floor in the concrete garage is not connected to the walls, a damper tape is laid around the perimeter (sold in hardware stores) or thin sheets of foam plastic (10 mm thick) are cut into strips. The width of the strips – 12-15 cm – they should protrude slightly above the floor finish. The excess height of the damper is then cut flush with the floor.
Waterproofing a concrete floor in a garage
Concrete itself is not afraid of moisture, high humidity is harmful to the car body, as well as to things and equipment, which are accumulated in the garage a lot. The choice of materials for waterproofing depends on how close the groundwater is and how high it can rise in season.
If the groundwater is high, no special waterproofing measures can be taken, but a dense plastic film (with a density of 250 microns or more, can be reinforced, can not) be laid on the sand. in this case, the film is more needed so that the moisture from the concrete does not go into the sand, which cannot be allowed. With a lack of moisture, the concrete will not gain the required strength and will crumble.
With a high level of groundwater, it is better to take a denser and more reliable waterproofing – waterproofing or its analogues. In any case, the film panels are overlapped – they overlap each other by 10-15 cm. To minimize the possibility of water penetration, the joints are glued with double-sided tape, it is possible twice (at the beginning of the joint and at the end).
Waterproofing starts on the walls, above the damper tape. She is temporarily fixed there. After the concrete has been poured and set, it can be cut.
Reinforcement
Since the loads are supposed to be serious, the concrete floor in the garage is reinforced. For passenger cars, you can use a ready-made mesh of wire 7-8 mm in diameter, the size of the cage is 15 cm. Two meshes are connected to each other with plastic clamps or special knitting wire.
Another point – the mesh should be in the thickness of the concrete, approximately in the middle. It would be wrong to simply lay it on the film – the metal does not corrode inside the concrete only if it is at a depth of at least 3 cm. In order for the concrete floor in the garage to serve for a long time and not crack, the mesh is raised above the waterproofing by 3-6 cm. There are special coasters for this, but halves of a brick are more often used. They just have a thickness of 6 cm. Place them under the reinforcing mesh so that it does not sag very much.
Installation of beacons
In order for the floor in the garage to be even, it must be leveled. It is more convenient to do this with the help of a special long bar, which is called the “rule” (the emphasis on the letter “I” is from the word “rule”). This bar is supported on even bars, set to the desired level. They are called beacons.
As beacons, you can use any smooth and long objects. It can be pipes, bars, special beacons that are sold in hardware stores. They must be set at the same level with the level mark of the concrete slab applied on the walls.
Lighthouses are placed from the far wall, towards the one in which the doors are arranged (most often it turns out that along a long wall). The installation step is 25-30 cm narrower than the length of the rule. If the rule is 150 cm long, the distance between the beacons should be 120-125 cm. About 30 cm recede from the wall, put the first beacon, then others with a given distance.
They are usually installed on islands of densely mixed solution. They lay out the slide a little higher than necessary, press the beacon into it so that it is at the right level.
When installing beacons, you can make a slight slope of the concrete floor towards the doors (0,5-1 cm per meter). In this case, the water will flow by gravity from the floor to the street. Just note that in this case more concrete is required – you have to lift up the farthest edge of the floor from the entrance, but this is offset by ease of use.
The next day after pouring, the beacons are removed, the voids are filled with mortar and leveled to the same level as the previously filled floor.
pouring concrete floor in garage
The brand of concrete for the floor in the garage is M250. Its characteristics are more than sufficient both in terms of strength and frost resistance. Due to the fact that the thickness of the plate is large, even a small garage requires a large volume of mortar. Let’s figure it out: for a small garage measuring 4 * 6 m with a concrete floor thickness, 4 m * 6 m * 0,1 m = 2,4 cubic meters will be required. Taking into account the fact that a slope is needed, it will be all 3 cubes. If you do it yourself in one day, you need to use two concrete mixers – one will not cope. It takes a decent team to get the job done.
There should be one person on each concrete mixer. This is provided that all the components are right there and they will also load them into the pear. If the components need to be brought up, this is two more people. Plus, two have to carry concrete to the place of its laying and one – to level. It turns out a considerable brigade. Such a composition will have to work all day. Even if the helpers are free, they need to be fed and watered. It is unlikely that this alignment will help save a significant amount of money compared to ordering ready-made concrete from the factory. Unless you will work in one hand, pouring the floor in parts. This is also possible, but it can threaten with cracks at the joints of floor sections flooded on the same day. You can reduce the chance of such cracks by removing the cement laitance that forms on the surface with a metal brush.
If you decide to order concrete in a mixer, you should install a receiving tray that will direct the flow of concrete to the center of the garage. From the center it is already easy to distribute it to all corners, and then stretch it with a rule. To facilitate the leveling of concrete and increase its grade, immediately after the preliminary distribution, the concrete is treated with a submersible vibrator for concrete. At the same time, air bubbles immediately come out, the concrete becomes more fluid and fills all the cavities itself. Lighthouses will be needed only for orientation and, perhaps, partial alignment.
Curing
After pouring concrete, if it’s not very hot outside, you can simply close the garage doors. If there is a window, it must be hung so that the sun’s rays do not fall on the concrete. If the street is too dry and hot, the concrete is covered with plastic wrap or damp burlap.
During the week, the stove should be watered daily. It is more convenient to do this over burlap – you can water the burlap without much suffering in relatively small streams, and it will give moisture to the concrete. If the concrete floor in the garage is covered with a film, it is removed before watering, then stretched again. When watering, in this case, you need to make sure that the drops are small – you need a nozzle with a large number of holes. In any case, the degree of watering is to a uniformly wet state (determined by the dark gray color of the surface), but without large puddles.
Insulated concrete floor in the garage
There are two options – to insulate an already filled slab, pour a screed on top (the structure in the figure below) or make insulation right away by laying it under the main slab.
When choosing the second option, the insulation is laid on top of the waterproofing layer, a reinforcing mesh is placed on it. The rest of the process of pouring the concrete floor in the garage is similar, only it is necessary to take into account the thickness of the insulation when calculating the depth of the pit.
As a heater for this case, it is recommended to use extruded polystyrene foam (EPS) with a density of at least 35 kg / m3. It has very good characteristics, can withstand heavy loads, does not absorb or let water or steam through. So it is also an additional vapor barrier.
In order to be sure that the insulation will not be squeezed under the wheels, it makes sense to lay a layer of geotextile on top of it. This is a non-woven membrane that is used in the construction of roads. Its function is load distribution, just what we need.
The minimum thickness of EPS is at least 5 cm, better – 8 cm. It is better to lay in two layers, shifting the seams when laying – in order to isolate the floor from the ground as best as possible.