Part of our complete guide
Basement Construction in Singapore: A Buying Guide →Key takeaways
- Retaining the house changes the investigation and temporary-works problem.
- The site access and neighbouring buildings matter alongside the intended basement size.
- Ask for a feasibility conclusion with explicit unresolved conditions, not just an excavation allowance.
Ask whether retention is part of the brief
Creating a basement below an existing house is a different proposal from building a basement while the house is reconstructed. Tell the engineer precisely what you want to retain and why. The team needs to establish whether the intended outcome can be achieved with an appropriate structural and construction strategy.
BCA’s structural process includes foundations, retaining and stabilising structures and geotechnical considerations where applicable. The required professional scope depends on the works. A generic contractor estimate cannot substitute for that assessment.
Sources: Building and Construction Authority: Structural Plan submission
Commission evidence in connected groups
Ask the engineer and design team to specify the necessary investigations rather than ordering isolated reports yourself. The useful result is an explanation of how the findings affect the retained-house proposal.
| Evidence group | What the feasibility review should resolve |
|---|---|
| Existing building | What structural information is available, what is verified and what needs investigation? |
| Ground and groundwater | What site information is needed to select and assess the construction concept? |
| Neighbouring properties | What could be affected, and what condition recording, assessment or monitoring is appropriate? |
| Boundaries and services | Where are the relevant legal and physical constraints, including drainage and sewers? |
| Construction access | How would plant, materials and excavated material move through the actual site? |
| Temporary conditions | How would the retained building and surroundings be supported and protected during the sequence? |
Feasibility brief, not instructions for excavation or structural support.
Inspect the access assumption
A basement can look straightforward on a section while the site entrance, side passage or street context makes the assumed construction logistics unrealistic. Ask the builder and engineer to assess access together. Include what can be placed on the site and what would depend on separate permission.
Do not accept an equipment choice or construction method solely because it was used on another house. The project-specific ground, structural and surrounding conditions must drive the technical decision.
Treat neighbours as part of the engineering review
BCA and URA’s advisory guide discusses excavation impacts, pre-construction records and engineer assessment of surrounding properties. Ask what scope applies here and how the findings will shape design and monitoring. A neighbour’s willingness to cooperate does not establish that the works are technically acceptable.
Get a conclusion you can act on
Request three outputs: the feasible options identified so far, the unresolved facts that could change them, and the next investigation or design appointment. Ask which option preserves the household functions you need and which requires a different retention strategy.
Compare a retrofit with reconstruction or another space solution using the same desired outcome. If the feasibility work shows that preserving the house prevents an acceptable basement solution, record that clearly before proceeding to a detailed construction commitment.
Sources and scope
Our editorial team checked the references below. Manufacturer guidance applies to the products and arrangements it describes; confirm the documents for your proposed installation.
- Structural Plan submission
Building and Construction Authority · Checked
Structural-plan applicant qualifications, permit process and additional certification considerations for A&A.
- Be Good Neighbours, amended October 2025
Building and Construction Authority and Urban Redevelopment Authority · Checked
Advisory guidance for landed-house works: neighbour engagement, surveys, excavation impacts, party-wall and roof interfaces.
All basement construction resources →
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About the author
Written by the DirectHome team, Singapore home-upgrade contractors coordinating licensed lift, pool, roofing and gate specialists. We coordinate BCA-permitted works through licensed specialist partners across landed property in Singapore.
