Our Services
Deep Sewer Estimates
1️⃣ Why Do Sewer Runs Get Deep?
- Sewer mains operate on gravity flow, so they must be laid at a grade.
- As the run gets longer, it gets deeper to maintain the correct slope.
- Sometimes, the sewer run itself is not deep, but it must connect to an existing deep manhole (e.g., 10m deep).
- Deep sewer work is complex, slow, and expensive, so accurate costing is critical.
2️⃣ Excavation Challenges in Deep Sewer Work
📌 Trench Support is Mandatory Over 1.5m Depth
✅ Option 1: Benching (If Space Allows)
- The trench walls are cut back at a safe angle instead of using shoring.
- Requires lots of space, which is not always available in built-up areas.
- Time-consuming & increases excavation volume (more spoil disposal).
✅ Option 2: Shoring Boxes (If Space is Limited)
- Steel trench shields used to prevent collapse.
- Expensive to hire and require large excavators to lift & remove.
- A standard shoring box is ~2.4m deep, so for 10m depth, multiple boxes are required.
📌 Crew Safety & Extra Manpower
- A dedicated person must be stationed above the trench to coordinate between the ground team and the workers inside the trench.
- Ensures efficient material handling and crew safety in deep trenches.
3️⃣ Key Cost Factors in Deep Sewer Estimation
✔ Shoring Hire Costs – Number of shoring boxes needed depends on trench depth.
✔ Excavation & Spoil Removal – More depth = more material to remove & dispose of.
✔ Machinery Requirements – Larger excavators needed to dig and handle shoring boxes.
✔ Extra Crew Members – A dedicated top-side coordinator is essential.
✔ Compaction Testing – Mandatory at every 150mm layer when backfilling.
✔ Level 1 Geotech Supervision – Required for depths over 3m (additional cost).
4️⃣ Why Experience Matters in Deep Sewer Estimation
💡 Missing just one key factor can cause major cost overruns.
💡 WSE Sydney has the experience to price deep sewer projects correctly.
💡 We factor in:
- Shoring & excavation method (benching vs. boxes).
- Equipment, crew, and safety coordination costs.
- Compaction testing & geotech requirements.
📞 Need expert estimation for deep sewer work?
📧 tenders@watersewerestimatingsydney.com.au
📞 +61 451 404 645
