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Buy lean concrete ready - Strength & Prices - Instructions for self mixing

  • Lean concrete - what you should know
    • Use of lean concrete
    • Prices for ready-mixed concrete
  • Mix lean concrete
    • material
    • manual
    • porous concrete
    • Apply cleanliness layer
  • Buy lean concrete ready
  • Tips for quick readers

Lean concrete is a mixture of cement and concrete aggregate. This supplement is the same gravel-sand mixture that is used in normal concrete. Normal concrete for the construction of pressure-resistant structures is mixed in a ratio of one part cement to four parts aggregate. In contrast, lean concrete receives only half of cement - it is mixed in the ratio of one to eight. This makes this building material very cheap, but this is at the expense of its strength.

Lean concrete - what you should know

What can normal concrete ">

Use of lean concrete

Lean concrete is often used in horticulture. It is well suited for setting garden stones or as a foundation for fence posts. If it's just a question of giving a tight grip to a construction that is only slightly loaded, then lean concrete usually suffices completely. Even simple wooden huts such as carports, garden or equipment sheds can be well equipped with a foundation of lean concrete. This keeps prices low for these lightweight buildings. However, a brick garage can no longer be built with lean concrete. In this case, a pressure-resistant concrete must be used for the foundation.

A particularly popular application for lean concrete is the so-called "cleanliness layer". This is a layer about 2-5 cm thick, which is inserted immediately after digging a pit. A layer of cleanliness is a quick and easy way to prepare the excavation for all further work. After rainfall, no mud forms in the pit. The stagnant water does not seep through the layer of cleanliness. But it can now be pumped off easily. Immediately after pumping the pit is accessible again. Without a cleanliness layer that would not be possible.

In addition, lean concrete can also be used well for slope stabilization. For this purpose, the concrete is poured out at the edge of the pit and reinforced with a welded steel mat. This prevents the slope from continuously softening during rainfall and slipping into the excavation pit. However, this does not work for deep pits with basements. The best way to protect the slope remains the sheet piling. A slope protection of lean concrete should not be used for slopes over one meter in height.

Finally, lean concrete is also very much used for filling well foundations. In contrast to unconnected gravel, lean concrete does not wash out.

Prices for ready-mixed concrete

Concrete, which is ordered ex works and delivered to the construction site, is called "ready-mixed concrete". He is hit in the mixed truck. The two-axle concrete transporters can deliver four cubic meters of concrete, the three-axle trucks have a capacity of six cubic meters. The biggest concrete trucks are the four-axle vehicles. They deliver eight cubic meters of concrete. It is therefore worthwhile to calculate exactly how much concrete is needed at what time. A 100 square meter size, 5 cm thick (0.05 meters), has a volume of only 0.5 cubic meters. This makes the ordering of a truck hardly worthwhile and makes the use of the blender more useful.

The prices are essentially based on the compressive strength class. The more pressure-resistant a concrete is, the more expensive it is. The most important factor for the compressive strength is the surcharge. Immediately afterwards come the cement type and the amount of cement added. Accordingly, lean concrete is of light aggregate and only a small proportion of cement. Surprisingly, the cheapest and the most expensive concrete types are only about 40 - 50% apart. However, considerable amounts of concrete are used up at a normal construction site. Typical prices for transported lean concrete are:

  • Lean concrete with a compressive strength class of c 8 - c 10: 89 - 91 euros per cubic meter
  • for drainage and filtration tasks (compressive strength up to c 30): 96 - 108 euros per cubic meter
  • Lean concrete for clean layers (compressive strength c 12): 99 - 101 euros per cubic meter

In addition, additional travel costs are added. These are divided into zones. These include circuits of 5 - 30 km and will be charged with 56 to 70 euros in addition.

It can be seen that the order of lean ready-mix concrete usually makes no sense. Handcraft is much cheaper and easier to implement.

Mix lean concrete

Mixing lean concrete is pretty easy. However, it is highly recommended to use a free fall blender. Hand blends are very exhausting and whirls on drills are quickly overwhelmed because of the gravel.

Fundamentals of concrete mixing machines

Before the manual for lean concrete is delivered, a few words on concrete mixers. There is a distinction between free-fall mixers and compulsory mixers. On a construction site, and no matter how small, basically a circular saw and a mixing machine belongs. Both devices are available today at such low prices that it is not worth abstaining. Also, the rental solutions are not useful, since both devices are needed over the entire duration of the construction site. Here we recommend, if necessary, to use a cheap but new machine from the hardware store. Prices start today at just under 200 euros per machine. Even if they fail after the construction project, they have nevertheless done their job.

Used machines are always at risk of breaking during work. Nothing is more important in a construction project than a continuous flow of work. Therefore, do not take any risks and buy new equipment from specialist retailers. With many devices and other places there are ways to save money on a construction site. For blenders and circular saws, however, you should always play it safe.


For lean concrete, you need:

  • Free-fall mixing machine: From 200 euros
  • Wheelbarrow: From 30 Euro - but we recommend fully galvanized wheelbarrows with solid rubber tires. These start at about 70 euros.
  • 2 shovels: Used from 5 euros or new from 15 euros.
  • Gravel From approx. 10 Euro / 1000 kg
  • Portland cement: From approx. 3 Euro / 25 kg bag.
  • water
  • 10-liter bucket: From 1 Euro (Mayonnaise Bucket from the Pommesbude)
  • Eye protection
  • Concrete pullers
  • Garden rake with handle: From 10 Euro


The drum of the mixer is rotated at an angle of 30-45 °. Then the machine is started.

Attention: Never reach into the running drum! When putting on concrete wear eye protection! Immediately rinse with cement splashes in the eye and consult a doctor! It threatens the loss of vision!

1. Pour a bucket of water into the mixer's running drum.

2. Then add a scoop of cement and wait for a cement slurry to form without lumps or dry nests.

3. Then add four scoops of gravel.

4. Now control the humidity. If the concrete is to be applied with pinpoint accuracy (eg for supporting low boards), the concrete must be drier. If the concrete is to be applied flat (eg for a clean layer), the concrete should be more fluid.

5. Add water as desired.

6. Then add another scoop of cement.

7. Then four more shovels add gravel. That should be enough for now. It does not make sense to mix too much lean concrete at once. The fuller the drum gets, the harder it will handle.

8. Now pour the concrete into the wheelbarrow and drive to the place of application.

porous concrete

Drainage concrete is open-pored concrete. It is also made of lean concrete. The instructions are to make it as dry as possible. The gravel thus adheres only selectively to each other. Drainage concrete is used to make the concrete layer waterlogged. It is very well suited as a "load distribution layer" under open terraces. For this purpose, the strength of the drainage concrete is completely sufficient. The advantage of drainage concrete is that it does not seal the floor. Rainwater can infiltrate and form no puddles. In addition, it is returned to the groundwater level. Drainage concrete is very welcome at building authorities, as they usually want to prevent the surface seal.

Apply cleanliness layer

Since the strength of lean concrete plays a less important role, the water can be handled quite generously. The more fluid the concrete is, the easier it is to spread. If a mild steel mat is left, it is worthwhile to insert it in the thin layer of cleanliness. The concrete puller is suitable for accurately applying the cleanliness layer. This can easily be made by yourself. That's what you need

  • broomstick
  • about 10-15 cm wide and 1.50 meters long board
  • 2 slats

The board is nailed T-shaped to the end of the broomstick. An angle is chosen that will allow the flat side of the board to rest flat on the floor when the operator holds the puller in his hand. Subsequently, the cross-board is fixed with the two slats triangular on the broomstick. This prevents wobbling during peeling.
The concrete is poured out as widely as possible. Then he is pulled apart with the rake and smoothed with the puller - done.

Buy lean concrete ready

Lean concrete can not be bought as bagged goods. Ready-mixed concrete as bagged is already very uneconomical in itself. Although it does guarantee strength, it can be achieved by following the mixing instructions given in the instructions. The prices for the precast concrete are far too high. If not very small amounts are needed, you should always resort to the self-mixing.

Too much concrete "> Tips for quick readers

  • Plan cleanliness courses for Friday afternoons. Here high-quality concretes can be ordered as surplus quantities inexpensively.
  • For cleanliness layers and slope supports, always use additional mild steel mesh if possible.
  • Underfill terraces with drainage concrete.
  • For ready-mixed concrete, calculate all quantities precisely. The more precise the amount of concrete, the more accurate the concrete can be ordered. Pay attention to the sizes of the transporters. only order full 4, 6 or 8 cubic meters. If necessary, ask the concrete factory which transport sizes are available.
  • Do not use lean concrete where high strength is required!

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