ERSS in Singapore: Earth Retaining and Stabilising Structures Explained

In short: ERSS (Earth Retaining and Stabilising Structures) is the BCA submission category for any temporary or permanent structure designed to retain earth, support excavations, or stabilise ground. It includes sheet piles, contiguous bored piles, secant piles, soldier piles, diaphragm walls, ground anchors, and soil nailing. ERSS submissions in Singapore must be endorsed by a registered Professional Engineer (Geotechnical), with movement criteria, monitoring plans, and — for higher-risk projects — an Independent Checker. Fees typically range from S$3,000 to S$15,000+. CVC Engineers handles ERSS submissions in partnership with our registered PE (Geotechnical) panel, with PE (Civil) coordination by Er. Cavan Chai (PEB Reg. 5376).

Key Facts

• Regulator: Building and Construction Authority (BCA) Singapore

• Required endorsement: Professional Engineer (Geotechnical), under Singapore PE Act

• When required: for excavations needing earth retention (typically depth dependent, with risk-class triggers), works adjoining other property, slope stabilisation

• Independent Checker: required for higher-risk Geotechnical Building Works under BCA's Regulation

• Typical fee range: S$3,000 to S$15,000+ for the PE (Geo) component; larger for complex deep excavation

• Submission timeline: 3 to 6 weeks for typical projects, longer for deep excavation and adjoining-sensitive sites

What Counts as ERSS?

ERSS covers structures whose purpose is to retain earth, support excavation faces, or stabilise ground. Common types in Singapore practice:

• Sheet pile walls — driven steel sections, typically for shallower or temporary works

• Contiguous bored pile walls — reinforced concrete piles drilled in a row, common in Singapore basements

• Secant pile walls — interlocking concrete piles, used where water cutoff is needed

• Diaphragm walls — cast in-situ reinforced concrete walls, used for very deep excavations and MRT works

• Soldier piles with timber lagging — for cohesive soils above water table, less common in SG

• Ground anchors — prestressed tendons used to tie-back walls

• Soil nailing — used for slope stabilisation and shallower retained heights

When Do You Need an ERSS Submission?

• Basement excavations for new buildings

• Deep services trenches near existing structures

• Slope stabilisation works

• Permanent retaining walls for landscaping or property boundaries

• Works adjoining MRT alignments, road reserves, or sensitive structures (LTA/PUB approvals also apply)

• Tunnelling support and ground improvement schemes

What an ERSS Submission Must Include

1. Site investigation report: soil profile, groundwater conditions, geotechnical parameters, classification.

2. Design calculations: stability, structural capacity, deflection, lateral earth pressures, water pressures.

3. Drawings: ERSS plan, sections, details, sequencing for excavation and construction.

4. Movement criteria: predicted and allowable movements for the wall, ground, and adjoining structures.

5. Instrumentation and monitoring plan: inclinometers, settlement markers, piezometers, vibrating wire strain gauges where appropriate. Trigger and action levels for monitoring data.

6. Adjoining property protection: pre-condition survey, dilapidation report, predicted impact on adjacent structures.

7. PE (Geotechnical) endorsement: registered PE (Geo) sign-off, plus Independent Checker for higher-risk schemes.

Pricing

• Small ERSS (shallow trench, simple sheet pile): S$3,000 – S$6,000

• Mid-size ERSS (single basement, residential / small commercial): S$6,000 – S$15,000

• Large ERSS (deep basement, multi-level, adjoining sensitive structures): S$15,000+, project-specific

• Note: fees are for the PE (Geo) component only. Site investigation, instrumentation, and contractor works are separate cost lines.

Common ERSS Mistakes That Cost Money

1. Inadequate site investigation: trying to design ERSS off thin SI data leads to over-conservative or under-conservative designs — both expensive in different ways.

2. Late engagement of PE (Geo): designing the building first then asking the PE (Geo) to retrofit a basement causes major rework.

3. Skipping pre-condition survey: without baseline data on adjoining structures, any movement claim becomes a costly dispute.

4. Ignoring monitoring data trigger levels: movement triggers exist for a reason. Continuing to excavate after a Level-1 trigger risks BCA stop-work order and structural failure.

About CVC Engineers

CVC Engineers Pte Ltd (UEN 202332143E) handles ERSS submissions in Singapore through coordination of structural and geotechnical scope. PE (Civil) endorsement and overall project lead by Er. Cavan Chai Han Hon, PEB Reg. No. 5376. PE (Geotechnical) endorsement is delivered through our strategic partner panel of registered PE (Geo) consultants experienced in Singapore deep excavation, ERSS, and tunnelling — properly credentialled, with CVC as your single point of contact.

300+ projects across HDB, LTA, PUB, MOE, MHA, BCA, and the private sector. Located at 9 Tagore Lane #B1-01, Singapore 787472.

Phone: +65 9342 7551 · Email: stephen@cvcengineers.com