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Trenching and backfill

As mentioned before, part of the pipework and some electrical wires run underground. For install these pipes we have to make trenches across the garden. Underground pipe installation for irrigation systems involves several steps, including trenching, pipe laying, backfilling, and restoration.

Most important thing to avoid unnecessary trenching during designing of the trenching layout. For example when lawn irrigation is required, then the cables and additional pipes will be adapted to run in the trenches that connect the popup sprinklers together. Usually primary pipes run under the tilling level in lawn and beds but they may be laid on the surface (bottom of a fence, behind matured hedge, etc.) when it’s safe and hidden to lay so to avoid costly trenching.Trenching is the process of excavating a narrow and deep channel in the ground to accommodate the irrigation pipes. The trenches are typically dug using trenching machines, mini-excavators, or manual labor with shovels. Our company prefers to use chain trenchers making 4-5 inches wide and 8-12 inches deep trenches. The depth and width of the trench may depend on the size of the pipes and other guidelines. 

Trenching


Trenching is the process of excavating a narrow and deep channel in the ground to accommodate the irrigation pipes. The trenches are typically dug using trenching machines, mini-excavators, or manual labor with shovels. Our company prefers to use chain trenchers making 4-5 inches wide and 8-12 inches deep trenches. The depth and width of the trench may depend on the size of the pipes and other guidelines.

Pipe Laying

Once the trenches are dug, the irrigation pipes are laid in the trenches. This involves carefully placing the pipes along the trench, ensuring they are properly aligned and connected by the manufacturer’s guidelines.

We recommend to mark the underground pipes with detectable marking tapes to avoid damages in case of any later soilwork. Ask our quote for that.

Crossing Driveways and Hard Surfaces

When crossing driveways or other hard surfaces, additional considerations and techniques are necessary to ensure proper installation and minimize damage. Best practice is laying the suitable size ducts for these pipes prior to laying the surface materials. The duct provides an added layer of protection against the weight or movement of vehicles and prevents accidental damage during construction or maintenance. When the irrigation project runs together with landscaping, we supply the ducting plan. If the installation happens in a matured garden, then it may be necessary a landscaper or builder to intervene in lifting up and laying back the slabs or other surface materials to recover everything in the best condition. Under surfaces with less load weight (e.g. pedestrian walkways, etc.), the HDPE/MDPE pipes may be laid without extra protection.

Backfilling

After the pipes are laid, the trenches are backfilled with soil to cover the pipes.

Backfill of trenching is always made layer by layer and with thoroughful compaction. Despite this, later sinkage might be possible depending on the soil conditions. Also you can expect some extra soil heaped up along the trenches at some areas.

Restoration

Once the trenches are backfilled, the area is restored to its original condition. This may involve leveling the soil, reseeding grass, or replacing any landscaping or hardscaping features that were temporarily removed during the installation process. Proper restoration ensures that the irrigation system is integrated seamlessly into the surrounding landscape.

Soil may include stones and building debris in unknown quantities. Collection/transport of any stones and debris are not quoted, and they will be backfilled. Due to the nature of this process the stones may remain near the surface after finishing the installation.

Later tillage operations of soil (for example lawn aerating) in the trenching area must not be carried out deeper than 3 inches to avoid damages of pipes due to their laying depth.

Inspection and Testing

Before completing the installation, it is crucial to inspect the entire system for any leaks, loose fittings, or other issues. Test the system to ensure proper water flow and functionality, and make any necessary adjustments or repairs as needed.

Professional installation and adherence to local codes and regulations are recommended for underground pipe installation, especially when crossing driveways or other hard surfaces. Proper planning and execution of the process help to ensure a reliable and efficient irrigation system while minimizing potential damage and disruptions to the surrounding landscape.