A foundation for garden walls must have a certain depth in order to be able to give the stones on top of it sufficient stability. Our guide shows what to look out for and how to proceed.
Depth of the foundation
The foundation for garden walls must be frost-proof in order to maintain its stability even in winter. This also determines the depth of the base. Only from a depth of 80 centimeters does the ground show more than 0 ° C, even in winter. However, it is better to dig a pit of one meter. This ensures that the foundation is not damaged, even in very cold winters.
In addition, there is enough space for a 20 centimeter thick layer of gravel, which is crucial for drainage.
Preparation - instructions
Before the foundation can be poured, appropriate preparations must be made. The following guide shows how to do it:
1. Set the width
The width of the foundation is determined by the width of the stones. The trench should be dug 20 centimeters wider than the stone width. In order to maintain these dimensions, it is advisable to mark the course with wooden stakes and to stretch a cord between them.
This allows you to follow a straight line when digging.2. Digging
Manual digging with a spade is not recommended due to the depth. It is easier, faster and less expensive to rent a mini excavator and use it to carry out the excavation.
3. Fill in crushed stone
When the trench has been dug from a depth of one meter, the drainage layer can be filled in in the form of frost-resistant gravel. A layer depth of around 20 centimeters is sufficient. In order to achieve this layer thickness, however, at least 30 centimeters must be filled.
4. Compress
The gravel is compacted with a vibrating plate. If the layer thickness of 20 centimeters has not yet been reached, more ballast must be refilled and compacted again.
Pour the foundation
When the preparations are complete, the pouring of the foundation can begin.
The following steps are required for this:
- The pit is measured again to ensure that the foundation is the correct depth.
- A tarpaulin laid out on the edges of the pit can prevent the concrete from contaminating the soil in the immediate vicinity or from getting the substrate into the concrete.
- The concrete is mixed until a homogeneous mass is created.
- The mass is poured into the pit slowly and evenly. Care should be taken that no air bubbles form, if possible.
- The upper end must be leveled and smoothed to create a flat base for the subsequent construction of the wall.
- After the concrete has been poured into the foundation, it must be compacted. This can also be done more easily with a vibrating plate. The measure should be taken while the concrete is still damp. Air bubbles are pressed out and the distribution is adjusted.
- In order to avoid unevenness, a board should then be placed and a spirit level should be used to check whether the foundation for the garden wall is really completely flat.
Garden gate
If the wall runs around the entire property and a garden gate is also to be integrated, a correspondingly large recess is simply left free when the foundation is excavated. Because it is not necessary to pour a concrete foundation under the gate.
Corners
There are two ways of making corners in the foundation. The first variant is to dig the trench in such a way that the drainage layer and concrete run around the corner as desired. This variant is sufficient for low garden walls, and it is also extremely simple and practical. Because mini excavators and vibrating plates only have to be rented once. It is also possible to complete a large part of the work in one day.
The second option is to make the foundation in sections
build. One side is poured and compacted. When the minimum load capacity has been reached, two more trenches can be dug. Reinforcing bars are to be used at each end of the finished foundation as a connection for the new sections.Reinforcement bars
Reinforcement bars, also known as reinforcement bars, can be used when the foundation is exposed to greater loads. This is the case, among other things, if the garden wall is to be very high or very large and wide stones are used. They serve as reinforcement but also as a possible connection between two sections of the foundation. Therefore, among other things, they can be introduced to connect an already existing older section of the foundation with a new section. This is useful, for example, if a garden wall is to be extended.
Just like when pouring another section, for example if the foundation is to run around the corner. For this purpose, holes are drilled in the hardened concrete and the reinforcement bars are inserted into the holes up to half their length. The fresh concrete can then be poured.
Hints
In order for the concrete to set gradually and not cause cracks, a few points should be taken into account both when placing and after pouring the foundation for the garden wall. These are:
- The ideal temperature for pouring and setting is between 15 and 20 ° C
- the optimum humidity is 85 percent
- from 30 ° C there is a risk of cracking in the first week
- If there is no rain in the first three days, the concrete must be moistened
- Alternatively, cover with a vapor-impermeable film
- Foil must not touch concrete directly
- If frost occurs, use the heating cannon shortly after watering to avoid frost damage
- Before excavating and laying the foundation, it should be checked whether a permit is required