In this guide · 8 sections
Short answer
Serve each payment claim by the date in your contract (or by the last day of the month if the contract is silent), in a method the contract allows. The respondent then has up to 21 days under the contract, or 14 days by default, to respond. Track every date in a register and keep proof of service.
What the SOP Act does for contractors
The Building and Construction Industry Security of Payment Act took effect on 1 April 2005. BCA's SOP Act page says it gives parties with a written contract a statutory right to progress payments and a fast, low-cost adjudication process for disputes. It covers main contractors, subcontractors, consultants and suppliers.
Amendments made in 2018 and 2019 took effect on 15 December 2019. The full Act is on Singapore Statutes Online, and BCA publishes a flowchart, sample forms and an information kit. The timings below are from BCA's information kit and flowchart, checked in October 2026. Always read them against your own contract and get legal advice on a specific dispute.
Payment claim and response deadlines
The clock starts with the payment claim. Each step has a deadline, set by the contract within limits in the Act, or by a default where the contract is silent.
| Step | Construction contract | Default if contract is silent |
|---|---|---|
| Serve payment claim | By the date or period in the contract | By the last day of the month; not more than one claim a month |
| Payment response due | Contract terms, max 21 days | 14 days |
| Dispute settlement period | 7 days after the response due date | 7 days |
| Payment due | Contract terms, max 35 days after response due date or tax invoice | 14 days |
| Supply contract payment due | Contract terms, max 60 days after invoice (claim) | 30 days |
BCA's process flowchart also shows what happens next: if a response is missing or disputed and the 7-day settlement period passes, the claimant gives notice and can apply to the Authorised Nominating Body, currently the Singapore Mediation Centre, for adjudication.
What a payment claim must contain
BCA's information kit lists what a payment claim must do. In summary, it must:
- Be in writing and served on the respondent, or anyone else the contract specifies
- Identify the contract the progress payment relates to
- State the claimed amount for the relevant period
- Describe the items (work done, goods or services supplied) and quantity in enough detail
- Be supported by documents and calculations based on the contract or reasonable value
- Be served personally, by pre-paid registered mail, by fax, or by another method provided in the contract or the Act
BCA also publishes sample forms for claims and responses. Build your claim template from them so every claim carries the same fields.
Serving payment claims by email reliably
Email is how most claims are sent today, but BCA's list of service methods names email only through 'other methods of service as provided under the contract'. So the first check is the contract, then the mechanics.
Check the contract's notice clause
Confirm the contract allows email service and to which address or person. If it names an address, use exactly that one.
Send from a monitored company mailbox
Use a shared claims@ or accounts@ mailbox on your own domain, not a staff member's personal account, so records survive staff changes.
Make your domain trusted
Set up SPF, DKIM and DMARC so claims do not land in the respondent's spam folder. Large attachments and new domains are common spam triggers.
Attach a PDF, not just a link
A file-sharing link can expire or be blocked. Attach the claim as a PDF and keep supporting files a reasonable size.
Keep proof of sending
Keep the sent email with headers and attachments, and the delivery report. Read receipts are useful but can be declined, so do not rely on them alone.
Use a second method for big claims
Where the contract allows, also deliver by hand or registered mail for large or disputed claims, so service is hard to argue about.
Responses arrive by email too. Make sure the address in your contracts is monitored daily, has auto-forwarding to a backup person during leave, and is protected with MFA. A missed response deadline on your side has consequences too.
A claims register: track every deadline
A shared spreadsheet or your accounting system can work as a claims register. One row per claim, per contract.
Columns for a payment claims register
Calendar reminders for each response and payment due date stop deadlines slipping. Automations can create them when a claim is logged; our guide to automating invoice reminders in Xero or QuickBooks shows the approach for the payment side.
Tax invoices and the SOP Act
A payment claim is not the same as a tax invoice. BCA's information kit says that if the claimant accepts the payment response, it should notify the respondent in writing by submitting the invoice, a tax invoice if the claimant is GST-registered. For construction contracts, the payment due date can run from the date of that tax invoice.
So issue the tax invoice promptly once you accept a response, and make sure it meets IRAS's requirements. Our guide to GST tax invoice requirements in Singapore lists the fields IRAS requires and the 30-day issuing rule. Keep the claim number on the invoice so the two can be matched.
Do it yourself or get help?
A small contractor can run all of this with a template, a shared mailbox and a spreadsheet, if one person owns it. Your website and company profile matter for winning the work in the first place; see our guide to construction company websites and BCA grades.
If claims land in spam, our Emails Land in Spam Fix (S$249) sets up SPF, DKIM and DMARC. Xero / QuickBooks Integration (S$390) connects invoicing to your accounts, and Workflow Automation (S$390 per workflow) can log each claim and create deadline reminders automatically.
Frequently asked questions
By the date or within the period stated in the contract or agreed in writing. If the contract does not set one, BCA's guidance says a claim may be served by the last day of any month following the month the contract was made, and no more than one claim may be made each month.
For construction contracts, BCA's guidance says the response is due by the date in the contract, subject to a maximum of 21 days. If the contract does not specify a date, the respondent must respond within 14 days. If no response is given, the claimant may move towards adjudication after the 7-day dispute settlement period.
BCA lists service by delivering personally, pre-paid registered mail, fax, or other methods provided under the contract or in the Act. Email is commonly used where the contract allows it. Check the notice clause, use the exact address it names, keep proof of sending, and consider a second method for large claims. Get legal advice if unsure.
No. The payment claim starts the SOP process. If you accept the payment response, BCA's guidance says you should notify the respondent in writing by submitting the invoice, which must be a tax invoice if you are GST-registered. For construction contracts, the payment due date can run from the tax invoice date.
If the respondent fails to respond, disputes the claim, or does not pay by the payment due date, the claimant can apply for adjudication through the Authorised Nominating Body, currently the Singapore Mediation Centre, after the dispute settlement period and notice steps. The Act also gives other remedies, such as suspending work in some cases.