In the case of paving stones in the garden, its durability is primarily determined by a properly prepared substrate, i.e.substructure for paving stonesRead about the construction of the foundation, what layers are included foundation and see what it looks likescheme of the foundation for paving stones , depending on the permeability of the soil and the purpose of the path.
Substructure for paving stones - design
What are the functions of the substructure for paving stones?
Substructure for paving stonesit is the layer responsible for the even load transfer from the paving surface to the native soil. It also acts as a layer that protects against the effects of negative temperatures and is the basis for the correct arrangement of the ankle. Although the sand spread on the foundation is a leveling layer, too large differences in its thickness (in the absence of a poorly made foundation) may lead to unevenness of the surface. For an even distribution of the sand bed,the base for the paving stonesshould therefore be even and with a suitable slope. Defectivefoundationwill result in the formation of ruts or even the collapse of the entire surface of the paving stones.
Making the foundation for paving stones - 3 important rules
In order forpaving stone foundationto perform its function properly and for as long as possible, it must be designed and made in accordance with certain rules.
1. Thickness of the foundation layer
First of all, it is about the correct adjustmentof the thickness of the foundation layerto the planned load of the paving stone surface. For paths, the base thickness of 10 - 20 cm is most often used, but in the case of pavements on which there will be circular traffic, it should be 25 - 40 cm.
2. Base material
The base for paving stonesshould also be permeable to water, enable its quick, gravity discharge to the ground and in no case retain moisture. Therefore, most often, gravel, crushed stone, grit, slag or a mixture of sand and gravel are used to make the foundation.
Substructure for paving stones - diagram of the basic structure of a pedestrian walkway
1. Curb, 2. Foundation of the curb, 3. Native soil, 4. Base 10 cm thick,
5.Sand bed, 6. Paving stones
Fig. Bush
3. Laying the foundation layers
To ensure even arrangement and compactionfoundation for paving stones , the material should be placed in layers of about 10 cm and each mechanically compacted.
Note! If the native soil has very low water permeability, it may be necessary to make a sand drainage layer below the sub-base. The thickness of this layer should be up to 10cm.
Substructure for paving stones - scheme on the ground with low water permeability
1. Curb, 2. Foundation of the curb, 3. Native soil, 4. Drainage layer,
5. Geotextile, 6. Base 10 cm thick, 7. Sand bedding, 8. Paving stones
Fig. Bush
Geotextile for paving stones - when is it necessary?
Both in the case of using the drainage layer and in the presence of weak native soil with low cohesion, it is worth using a geotextile. It has a separating function - it does not allow the materials of the individual layers to mix. Its use brings many benefits. During execution, it allows for a much better compaction of the individual layersfoundation for paving stones , and then prevents the washing out and penetration of aggregate from the upper to the lower layers (under the influence of loads, not separated layers of the foundation mix with each other, as well as with the native soil). This will allow, for example, many years of efficient functioning of the infiltration layer, which will not be contaminated and blocked with elements coming from the foundation. It will also prevent the surface from collapsing as a result of washing away and destabilization of the bearing layer itself. The use of geotextile also helps to reduce the formation of ruts and the blasting of paving stones when the ground freezes.
Substructure for paving stones - scheme of road construction for vehicular traffic
1. Curb, 2. Curb foundation, 3. Native soil, 4. 30 cm thick foundation
thickened in 10 cm layers, 5. Sand bedding, 6. Paving stones
Fig . Bush
Cement stabilized sand foundation
"When writing aboutpaving stone foundationit is also worth dealing with a myth that has been created in recent times. Recently, especially among contractors, the material used to make the discussed layer is cement - most often in the form of the so-called sand and cement ballast. "
There is a misconception thatcement-stabilized sand foundationprovides greater stability and load-bearing capacity of the pavement. Meanwhile, most often the impact of such a solution on the parameters of the path or driveway is very negative, primarily due to the ability to capillary rise water.As a result, moisture is stored. It can wash out loose fragmentssubstructure for paving stonesAnother danger in this case are temperature drops below 0 ° C, causing the moisture accumulated in the layer to freeze and thus burst it.
Of course, there are cases where the use ofconcrete foundationis advisable or even necessary. However, this takes place only in strictly defined design cases and requires the fulfillment of a number of conditions, the most important of which are proper water drainage and verified soil bearing capacity. However, in no case should such a decision be made without consulting the designer.
Paving stone foundationis therefore a key layer both for the aesthetics and durability of paved surfaces. At the same time, the only moment when the correctness of its execution can be checked is the moment of construction. Therefore, it is worth paying special attention to it, for example by controlling the contractor's work.Otherwise, it may turn out that we will find out about possible mistakes only after many months or years, when walking around our own garden we stumble over the rut that grows every year …
