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Carrying out maintenance or minor repairs to the car, many try to do it themselves. In order not to lie under the car on your back, you need a viewing hole in the garage.
Dimensions of the inspection pit in the garage
You will not find strict recommendations on the size of the pit for the garage. They are based mainly on the parameters of the machine and their own height. The dimensions of the garage pit are selected from the following considerations:
- The width should be sufficient to make it comfortable for you to work in it. At the same time, it is limited by the distance between the wheels of the car – each wheel must have room to maneuver. On average, the width of the inspection pit is from 80 cm or more.
- Its length depends on the length of the car. Add 1 meter to the size of the car. This is enough for comfortable work.
- The depth is calculated depending on your height: your height + 10-15 cm. In this case, you don’t have to worry about hitting your head. If you need long-term work with your hands up, you can knock down a special stool of low height and stand on it. You can raise the floor a little more in the viewing hole due to wooden ladders.
Inspection hole in section
This is far from dogma. Everyone does as he sees fit. Some deep holes seem uncomfortable and they make them almost exactly in height, and sometimes even lower – 1,5 meters. If you take into account the clearance of the car, from the floor of the pit to the bottom of the car you get about 1,7-1,8 meters. You can do that too.
Another point in length. Sometimes a long hole cannot be made. Then it is made about half the length of the car, driving it in front or behind, depending on which part of the car needs to be inspected or repaired.
Now about where to place the pit in the garage. Usually it is slightly shifted to one of the walls, leaving a wide side for installing equipment, storing spare parts, etc. At the same time, there should be at least 1 meter from the edge of the pit to the nearest wall.
That’s all there is to it. Just note that we were talking about the final dimensions of the pit. When marking the pit, you will need to add thickness to the walls, and dig deeper to the height of the floor screed (if you do it).
What materials are they made from
The inspection pit in the garage (its walls) is laid out with bricks, heavy building blocks, made of monolithic concrete. If we talk about bricks, then it is better to use ceramic bricks: it is not afraid of moisture. The walls are made in half a brick or brick. The wall thickness, depending on the masonry method, is 12 cm or 25 cm. This must be taken into account when marking the pit.
Brick can be used on dry, dense soils. The groundwater level should be low. If the water is high, it is better to make the walls of the pit from reinforced concrete.
Building blocks also need to choose those that are not afraid of high humidity. These are concrete blocks. The rest, if used, then with mandatory external waterproofing, and this is not a guarantee that they will not crumble, especially if groundwater is located close.
With a concrete inspection pit, everything is simpler: concrete is not afraid of moisture, it only becomes stronger from it. Concrete grade M 250 is used to fill the walls, M 200 is enough for the floor. Why is that? Because during winter heaving, the main load falls on the walls. So that they do not “fold”, a margin of safety is required, which is achieved by reinforcing and using high-strength concrete. By the way, in order to avoid heaving of the soil under the garage, it is necessary to make a good blind area so that the water leaves and does not soak into the soil.
The wall thickness when filling the inspection pit with concrete is from 15 cm. The stacks must be reinforced. To do this, use a finished mesh with a wire thickness of 5-6 mm and a pitch of 150 mm (if the groundwater is deep) or knit a frame of reinforcement with a diameter of 10-12 mm. The reinforcement installation step is 20 cm. For greater strength, you can make a single rod to the bottom and walls, bending it accordingly.
Waterproofing methods
The inspection pit in the garage can be protected from moisture penetration in two ways: with the help of external waterproofing, which is carried out exclusively during the construction process, and internal, which can also be done during operation.
Outdoor protection
If the groundwater at the construction site of the garage is deep, lower than 2,5 meters and does not rise higher even in spring or after heavy rains, you can do without waterproofing. On the other hand, the hydrological situation is constantly changing, and where it used to be dry, water may appear. If a viewing hole in the garage has already been built, you cannot do external waterproofing. It remains only to use deep penetration impregnations to reduce the hygroscopicity of the walls. Therefore, if possible, make external insulation anyway.
How to prevent moisture from entering the inspection hole in the garage? Most often, waterproofing films or membranes are used (butyl rubber, aquaizol, etc.). They are laid in panels, covering the pit from one edge to the other, releasing 10-15 cm on each side of the pit onto the garage floor. The sheets are overlapped. They should overlap by at least 15 cm. To get a more airtight joint, they are glued with double-sided tape, it is possible in two strips – at the beginning and end of the “overlap”. The film is well straightened so that it fits snugly against the walls of the pit. During further work, it is important not to damage the membrane.
Internal waterproofing
Internal waterproofing is usually the impregnation of walls with coated waterproofing. If possible – composition for pools. It creates a waterproof dense film, very reminiscent of rubber. It has a blue color and after hardening it washes well. It is better to process the walls with this composition twice, or more.
Another option is a cement-based deep penetration primer. The polymer particles contained in it block the capillaries through which moisture penetrates through the thickness of the material. One such treatment significantly reduces the hygroscopicity of the material. In the case of water in the garage pit, at least two treatments are necessary (and even more is better).
Caisson device
There is another option to escape from the ground – to make a metal caisson. A box of appropriate sizes is made from sheet metal, treated with anti-corrosion compounds, and then installed in a pit. If the welds are sealed, there will be no water, but another problem may arise. With a large amount of water, the caisson can squeeze out. It is said to “float”.
To avoid such a situation, corners and rods are welded to the sides of the caisson from the outside, which go 1-1,5 meters into the ground. So that at the same time the volume of earthworks is not very large (the pit, taking into account these spacers, turns out to be large), you can cheat. Before installing the caisson, drive corners or metal rods into the ground, releasing their ends outward. You can weld them to the body of the caisson after installation. The pit will still have to be made larger (it is necessary to cook from the outside), but its dimensions will still be smaller. The second plus of this method is that the rods will be driven into dense soil, which means that they will better hold the caisson.
Another way to exclude the “floating” of the caisson is to make a hole in the wall at a certain height. If the water rises to its level, it will begin to pour inward. Water can subsequently be pumped out, the main thing is that everything remains in place. The inspection pit in the garage, arranged according to this principle, stood for more than 20 years – until the metal rusted.
Pit for collecting water
If the pit has already been built, and coating waterproofing or impregnation did not give the desired result, it is necessary either to arrange a drainage system around the garage, or to collect water in one place. To do this, a pit is made in the garage inspection hole, at one of its ends. Water accumulates in it, from where it is pumped out by a pump. In order for the system to work in automatic mode, a water presence sensor is installed, which, when triggered, turns on the pump.
Formwork is made under the pit, poured with concrete. Then they make the waterproofing of the pit along with the waterproofing of the entire pit. For reliability, you can also put a metal caisson inside.
Since in this case it is impossible to completely get rid of dampness, a boardwalk is knocked down on the floor of the pit. In order for the boards to rot, they can be impregnated with mining. If you do not like its smell, take a special impregnation for wood that has direct contact with the ground (Senezh Ultra, for example).
Insulation of a viewing hole in the garage
If you spend a lot of time in the garage, then you will most likely have heating. To warm up faster and faster, it makes sense to insulate the pit. EPS (extruded polystyrene foam) is best suited for these purposes. It withstands significant loads, is not afraid of dampness, does not rot, fungi and bacteria do not multiply on it.
The thickness of the EPPS to create a tangible effect is from 50 mm. Lay it between the soil and the wall of the pit. Then from the outside-inside the pit will look like this:
- waterproofing film;
- EPS;
- wall.
This is extruded polystyrene foam
Expanded polystyrene can also be laid under the screed at the bottom of the inspection hole. A reinforcing mesh is usually laid on top of it, and then concrete is poured.
How to make a viewing hole in the garage
After you have decided on the dimensions and what material the walls will be made of, what thickness they will be, you can start marking the pit. This can be done using pegs driven in around the perimeter. The second option is to pull the twine / rope between the stakes driven in at the corners. According to the markup, we begin to dig a pit. The earth is usually taken out and temporarily stored near the gate.
From brick: step by step photo report
Along with excavation, monitor soil moisture. If you have reached the design depth (required + floor screed thickness), but there is still no moisture, you can do without waterproofing. Those who do not want to take risks can be advised to immediately lay the film.
We level the walls. It is not necessary to achieve ideal geometry, but there should not be noticeable humps and pits. We also level the bottom of the pit, ramming, compacting the soil well. Usually a manual rammer is used. A layer of rubble is poured at the bottom (two times 5 cm), each layer is also carefully rammed. Next comes a layer of sand. It is enough 5 cm. The sand is moistened, rammed to a high density – so that the foot is not imprinted. Next, lay the waterproofing film.
We level it well, tucking it into corners. We lay the panels with an overlap of 15 cm, which we glue with double-sided tape. So that the edges do not roll, we press with improvised materials – boards, stones.
We lay a layer of insulation on the bottom, on it – a reinforcing wire mesh. We fill all this with concrete grade M 200. The layer thickness is at least 5 cm. To make it easier to navigate when laying, we make marks on the film by which you can control the layer thickness.
If you use Portland cement M 400, the proportions will be as follows – cement 1 part, sand – 3, crushed stone of medium and fine fraction – 5 parts.
We are waiting for several days until the concrete gains 50% strength. The exact time depends on the temperature. If it is around + 20 ° C, you will have to wait 5-6 days. If +17°C it’s already two weeks.
Let’s start laying out the walls. It was decided to do in half a brick. We used used bricks, about 850 pieces went (pit size 4,2 * 0,8 * 1,7 m). Up to the level of the elbow, the walls were laid out in a circle.
At the level of 1,2 meters from the floor, it was decided to make a niche for the tool. Its height is 3 rows of bricks, the top is covered with a processed board.
In order not to have to lay out a brick niche, a metal insert is inserted. Welded box, suitable in size.
Further, the walls were driven out almost to the level with the garage floor. Part of the walls was replaced by two sections of channels. Jacks rest against the bottom if necessary. A metal corner with a shelf of 50 mm is laid on the top row, the thickness of the steel is 5 mm.
The corner is unfolded so that one of its shelves is hung down, the second covers part of the upper surface of the brick. So that the wall does not collapse under load, mortgages are welded to this corner, which are then connected to the reinforcing belt of the concrete floor in the garage.
Further, preparatory work was carried out on the installation of a concrete floor and it was poured with concrete.
Features of the manufacture of concrete walls
When casting concrete walls, it is necessary to make a formwork. It is easier to make it from sheet material – building moisture-resistant plywood with a thickness of 16 mm or more, OSB. They knock down shields of the required size, strengthen them with bars on the outside. They are necessary so that plywood or OSB does not bend under the pressure of concrete. First put the outer parts of the formwork. If the walls of the pit are even, there will be no problems. You just lean them on, put them straight.
Then the internal formwork panels are exposed. Between them there must be a distance of at least 15 cm. So that during the pouring process the walls are not deformed, spacers are placed between them.
Filling is desirable to carry out at a time. Filled portions must be bayoneted or processed with a submersible vibrator for concrete. Remove the formwork after two or three days. After that, you can install a corner with welded embedded rods (strips) and proceed with pouring the floor.